Blowers are installed away from the kitchen for quieter ventilation, especially when ducting is longer than ten feet. Inline blowers connect along the ducting line and are designed to push and pull air through the venting. Hoods are rated by CFM, or cubic feet per minute, which measures how many cubes of air are exhausted by the blower in one minute. There are three main types of blowers: local/internal blowers, inline/remote blowers, and external blowers.
A local blower is a blower directly inside your range hood, providing a space-saving solution as they eliminate the need for a bulky blower integrated into the range hood. Inline blowers are designed to push and pull the air through the venting, extracting the air outward and can be installed to an outside wall or roof. They consume more electrical power than an internal blower because they push.
There are three main types of ventilation systems: internal blower, inline/remote blower, and ductless hoods. By weighing the pros and cons of each type of hood, you can make the smartest choice for your kitchen. The Awoco unit is the top pick for the best external inline blower fan for range hoods, rated at 800-cfm and suitable for large kitchens and homes.
External blowers are located externally, usually on the roof or outside wall, usually on the roof or outside wall. For the quietest vent hood operation, choose an inline system where the blower is located in the attic or some remote location. An inline blower is installed within the ductwork of a ventilation system, used to boost airflow through the ducts, especially in situations where the kitchen is far from the kitchen.
Thermador’s in-line blowers provide exceptional performance and reduced sound levels by moving the blower mechanism away from the point of use. Their inline blowers are engineered to provide powerful and efficient ventilation for your kitchen, effectively removing cooking odors, smoke, grease, and other unpleasant smells. They can be mounted remotely to minimize blower noise and are available in a range of CFM ratings to match your cooking needs.
📹 Make Up Air for a Kitchen Exhaust – Most Homes Suck. (Pun intended)
Tel: 800.747.1762, ext. 3 [email protected] Read into the code here: (skip to 1503.6) …
What is the difference between inline and external blowers?
Internal and external blowers are two types of air purifiers that differ in size and design. Internal units are smaller and more compact, making them suitable for limited space applications. However, external units can be installed in separate rooms, saving space.
Budget is another factor to consider. Internal blowers are generally less expensive due to their smaller size and fewer materials required. However, smaller motors also result in reduced power and airflow, making them suitable for projects requiring a powerful blower.
Project requirements also play a role in choosing between internal and external blowers. If you need a powerful unit to handle a large volume of air, an external blower is the best choice. Conversely, if you have smaller space and don’t need as much power, an internal blower may be the best choice. In summary, the choice between internal and external blowers depends on factors such as space, budget, project requirements, and project requirements.
What is an inline fan used for?
Inline fans are mounted inline with ductwork, bringing air from the inside and outside of a home. They are useful for various applications, including ventilation of wet spaces, remote fans for kitchen range hoods, and continuous whole-house ventilation. Inline fans come in various configurations, sizes, and capabilities, such as single-port units with one incoming supply duct and one outgoing exhaust duct, or multiport versions with multiple ducts with a minimum of one inlet and one exhaust.
By varying duct sizes, inserting “Y” fittings, using adjustable grille openings, and varying fan speeds, different ventilation rates can be achieved for each location connected. Multiport versions are suitable for larger-scale single-family, multifamily, and commercial buildings. Inline fans have a range of airflow capacities from 100 CFM for housing needs to 2, 000 CFM for commercial applications. Manufacturers offer a variety of sizes, flow capacities, ducting configurations, controls, and accessories.
Is there a difference between a blower and a fan?
When choosing between a fan and blower, consider their functionality. Blowers operate at moderate pressure, with an air pressure ratio of 1:1. 1 to 1:1. 2, and can move large volumes of air with little to no change in pressure. They direct air in a specific direction, while fans circulate air throughout a defined space. Blowers are used for cooling, ventilation, drying goods and surfaces, cleaning surfaces, and increasing the size of a fire.
What does an inline blower do?
Inline fans are essential in homes for ventilation, removing odors and excess moisture from spaces like bathrooms, kitchens, and laundry rooms. They also circulate air, making homes more comfortable. When using an inline duct fan to expel odors and filter out VOCs, it is recommended to pair it with a carbon filter. Carbon filters are the best way to purify a space, and there are inline fan and carbon filter combos available on our site. Choosing the right fan is crucial for several reasons, including ensuring proper ventilation, reducing odors, and ensuring comfort in the home.
What are the two types of combustion blowers?
Centrifugal blowers are gear-driven machines that are capable of rotating at speeds up to 2900 rpm. These devices are more efficient than single-stage blowers, as they do not require a significant number of turns and can achieve higher pressures, up to 1500 mmWC. Such devices are frequently utilised across a range of industrial sectors, including power generation, transportation and agriculture.
What is an inline blower range hood?
Inline blowers, also known as inline blower motors or inline fans, are remote blowers located inside ductwork between the range hood and the end of the ducting. They are less expensive than local blowers and offer less power but are quieter. They are ideal for frequent guests or those who enjoy socializing with friends and family. Inline blower motors can vent up to 1300 CFM of air out of a home, making them suitable for various cooking styles. Proline Range Hoods offers the only hoods with an inline blower option, which can be paired with any of their three types of blowers: 1200 CFM local, 1700 CFM local, or 1300 CFM inline/remote.
What is the most efficient type of blower?
Centrifugal blowers are efficient and compact machines with a long-life external rotor motor, providing high aerodynamic efficiency. They draw air parallel to the drive axis, deflect it 90 degrees, and discharge it radially. They operate at high system pressures, primarily between 0. 35 to 0. 70 kg/cm2, but airflow drops if system pressure rises. All rotating parts are balanced, reducing noise and creating a uniform load on both bearings. Backward curved blades are typically used for intake suction, while forward curved blades require scroll housing.
They are used in various applications, including climate-controlled cabinets, conveying operations, medical devices, ovens, kitchen stoves, and sterilization units. Positive displacement blowers, or rotary air blowers, trap air in rotors and push it through the housing, ensuring consistent airflow regardless of changes in system pressure. These blowers are ideal for applications prone to clogging and are used in aeration, conveying, and vacuuming applications across various industries.
What is the purpose of an inline fan?
Inline fans are mounted inline with ductwork, bringing air from the inside and outside of a home. They are useful for various applications, including ventilation of wet spaces, remote fans for kitchen range hoods, and continuous whole-house ventilation. Inline fans come in various configurations, sizes, and capabilities, such as single-port units with one incoming supply duct and one outgoing exhaust duct, or multiport versions with multiple ducts with a minimum of one inlet and one exhaust.
By varying duct sizes, inserting “Y” fittings, using adjustable grille openings, and varying fan speeds, different ventilation rates can be achieved for each location connected. Multiport versions are suitable for larger-scale single-family, multifamily, and commercial buildings. Inline fans have a range of airflow capacities from 100 CFM for housing needs to 2, 000 CFM for commercial applications. Manufacturers offer a variety of sizes, flow capacities, ducting configurations, controls, and accessories.
What is the purpose of a blower on a wood stove?
Free-standing stoves, including those with legs and pedestal models, are designed with the primary objective of heat distribution, as opposed to circulation around an enclosure. The installation of a blower on a free-standing stove represents an effective method for the rapid and efficient distribution of heat. Similarly, stove blowers assist in the uniform distribution of air, thereby performing a function analogous to that of ceiling fans.
Is an inline extractor fan better?
Inline extractor fans are increasingly popular for domestic ventilation due to their higher power and less noise compared to standard axial bathroom fans. They can be used to push or pull air, depending on their orientation and desired airflow direction, making them the best choice for ceiling voids or lofts. They are not installed physically into the room, making them a more efficient and quieter option.
What is an external blower for a range hood?
An external blower is a box containing a ventilator, filter, and motor for ventilating air from a cooking stove. It can be placed outside the house or deep into the house. The blower boxes are made of stainless steel, and their ducts are made of aluminum to reflect heat into the house. External blowers clean hot gases from the stove while directing fresh cold air into the house. They consume more electrical power than internal blowers because they push hot gases to longer distances. They produce less noise and are more effective than internal ones because they do not recycle hot gases but replace them with colder fresh air from outside the house.
Installation of an external blower is complex and time-consuming, making it necessary for a professional to install. The range hood must be connected to the blower via a series of conduits recessed into the walls. The conduits should be made straight upwards outside the house to minimize corners and hide them into the walls to prevent unsightly and disorganized appearance. If conduits do not pass through the walls, they must be made of reflective material to prevent heat loss from inside the house to the outside.
📹 Why Your Stove Needs A Vent + Learn How To Install Your Own
I was so focused on trying to explain why the vent is important and how I built mine that I completely forgot to tell you that I have …
Matt, I’m an electrician in Georgia. When I tell mechanical guys and GC’s they need make-up air, they look at me like I’m crazy. Had a customer on a recent job call me and ask why his house smelled so bad when the exhaust fans were on. His house was so tight, and with no make-up air, the exhaust was breaking the seal in a P-trap and you could smell the septic tank. Repeatedly told the contractor we needed make-up air on that one. Now they just crack the windows.
Similar science, albeit applied differently, to what I deal with at work. Indoor ranges for military training have precisely tuned intake and exhaust in order to flow a specific cfm, but at all levels. Floor, waist, head, and ceiling across an entire room and for the length of the facility. Sometimes as much as 100 meters. All to ensure that the spent gases and lead particles are exhausted and filtered properly, maintaining soldier health. Nice article showing the importance of fresh air, especially in tight homes.
I used to work as a chimney sweep. We would get calls all the time for smokey fireplaces due to downdrafts. Much of the time the issue was a tight house with a strong kitchen exhaust fan. Half of the rest was no make-up air for the furnace. Then it was stack effect, those big open staircases that are all the rage right now. Finally, in about 1% of the cases, it was some issue with the chimney (usually location of the house) which resulted in outside air pressure creating a downdraft.
I installed this system in my house a few years ago and I can confirm that having the MAU is a massive improvement. The hood performance is much better than the higher cfm fan I had in my last house. I did have a problem with the outside air damper about 3 months after running this. I strongly recommend getting a higher quality actuator at some point. Other than that, this system has been great.
Note also: an incorrect draft into the home will reverse the chimney draw and you wake up dead from Co Their phemonom also and sometimes happens in a atmospheric temperature inversion. Warm air get trapped under a pocket of cooler air (in the clouds) setting off everyone’s Co detectors. A false/positive.
Hi Matt, when I design a range hood one of the most important things I find to have it work well is a capture area where the filters are at the top and you have the sides and front come down as much as possible this created a natural collection point for the heat and steam and the suction and filters work so much better. For make up air I put in a an outside make up air grill usually in the floor neat the cooking range hood this comes open when the hood fan is active with an air movement switch.
Nice article. I used to be a mechanical engineer specializing in HVAC systems (not anymore though). I learned some new things from your article. It might be nice if they could use a heat exchanger so that the makeup air could be heated in the winter or cooled in the summer by the exhaust air. I’m sure they have a good reason for not doing it though. The exhaust air might have a lot of grease in it that could foul it up.
Matt, just a home person but learning so much from you. We are 60 plus newly retired. Now looking for a resale to do some basis contractor remodels on and this is one area of concern for us. Also love your house and the pantry – we found a house we like that has laundry like yours behind kitchen we want to make walk in pantry but wasn’t sure how or where to move laundry. I saw your stacked smaller washer/dryer and the light went off. Can you tell me which you went with for those? Thanks.
Really interesting! It’s always fascinating when you encounter something counter-intuitive like the passive make up system! Different note: I went with induction about a year ago and have never looked back. It’s so much better in pretty much every way and the air quality issue has become one of the top selling points for me… and it wasn’t even a consideration when I bought it.
I did testing of commercial cooking hoods, and we used to bring in the make up air right around the perimeter of the hood, to create a Venturi effect. We then wired in the makeup unit ( which supplied conditioned outside air ( heated or cooled). Bringing in the makeup air right at the hood also eliminates having a draft between the makeup air and the hood.
When eight inches isn’t enough. The 3:1 passive rule of thumb has served my company well over the years. Fighting with customers over the need has never been fun. I appreciate these articles from Matt. I have customers who will believe the Internet over me. After all, I can’t possibly be motivated by anything but greed, right?
Loving the content at your house, my dream is to build my own one day and I would have never known all the building techniques and technology like I do now after perusal your show for 3 years or so now, I can’t wait for the day to come that I build my own yeti cooler house/monopoly house. Ive definitely learned a lot! Thanks so much Matt
Excellent material on a topic not very well understood by most homeowners. Some things to consider: 1) Energy efficiency. If you are pumping 1000 cfm of conditioned, humidified, and filtered air out of your house, and replacing it with outside air that is significantly hotter/cooler/drier/wetter, then your HVAC system is going to have to do some work to maintain a comfortable living environment. A 3000 sq. ft. home, running a 1000 CFM extraction system, is theoretically going to exchange 100% of the inside air for outside air in a little more than 20 minutes. That’s going to cost some amount of money in either heating or air-conditioning running costs. You can reduce this, potentially significantly, by utilising a heat-exchanger where the warmed/cooled inside air is used to condition the incoming make-up air. But these systems add complexity and cost. And you need to have the space and ducting routes to utilise them. 2) Speaking of which….The reality is that considerably less than 100% of our housing stock can use outside air extraction. In many instances people live in multi-unit apartments, condominiums, or other structures that simply do not offer a clear route from cooktop hood to the outside. And even in single-family houses, we need to remember that there are practical limits on the length of ducting (and number of turns) between hood and extraction port. 3) Another alternative, which doesn’t rely on makeup air, is a recirculating system. Rather than venting cooking smoke/smells to the outside, instead it relies on a series of filters.
What he doesn’t point out is that this is only “easy and simple” to install when you have new construction and everything can be designed around it. Otherwise retrofitting such a system into most older homes can be difficult and very expensive. I got quotes anywhere from $12k-$15k to install an active makeup system in my house. Even passive systems were $5-6k
@Matt Risinger So I just replaced my MicroWave Oven (MWO). New GE one runs the exhaust fan continuously every time the MWO is in operation! It runs on low speed at approx 300cfm. Soooo, that is really bad for my heating/cooling and its loud. Not sure how to deal with it and wondering what other MWOs have this “feature :)”. GE just a little backwards here, something about protecting their equipment from overheating but most MWOs run an internal fan to cool their components. I think they are telling consumers that theirs is also an internal fan but I disconnected the exhaust duct and verified that its exhausting to the outside during operation. Doubt many/any consumers/installers/builders know this. What fun!
Great article. This answers a question I’ve had for a long time, and is directly relevant to your article about radon gas. I live in an older house with a non-encapsulated crawl space in a high-radon zone. When I turn on the kitchen vent or even a bathroom fan, I try to simultaneously crack a window, because I know that the negative pressure is going to suck crawl-space radon gas through every gap in the subfloor, un-caulked electrical or plumbing hole, space around HVAC registers, or even improperly sealed ducting in the crawl space.
Matt learn how your equipment works. The yellow tube is to the B website that tells the DM32 the pressure differential across the Fan (as selected by the user). The red tube is for the pressure differential inside to outside (A website). The reference for the inside is the adjacent Blue tube connection. I have done over 2500 Blower Door Tests in 4 years. Remember the accuracy of the DM32 manometers is in the tenths of pascals. From what I have read positive pressure inside is preferred over negative pressure. I don’t understand why you chose a separate makeup air system instead of using your air exchange system for the makeup air. Other brands of air exchange systems regulate airflow using pressure differential. You added a separate system with additional cost and maintenance. I love the induction, but it is treated as technology. It is not considered repairable. So when one of those diodes dies in the hob the hob is useless. That means you are spending thousands to replace your cooktop every 3-5 years over a failed $5 part (and landfilling the old cooktop). You can still get replacement nichrome elements (70+ year old tech) for coil cooktops today. We’re currently waiting on China to deliver our next generation of induction cooktops with very short life expectancies. Tell me how filling landfills to enrich the CCP (and associated USA importers) with glass and computer parts is environmentally friendly.
As someone who takes cooking very, very seriously, to me, induction is the best choice for cooking in addition to the benefits Matt mentioned. The heat up times, searing power, etc are all superior to gas. It’s just a better cooking experience. I have been using a miele that is very similar to the one Matt has (36″ vs 42″ but otherwise the same) for 4 years now and I’m never going back.
Excellent teaching article every customer should watch this In all my decades I have only seen one properly installed fan that was not installed by me. I like to boil for very large pots or frying pans of water on all four corners of the burner simultaneously with the fans off just as a demonstration to show the customer how much bleed of smoke or grease that would be coming into the house. And then I turned their fan on to show them how their improperly installed Fan it’s still rolling over and bleeding around the edges into the house if it was invisible burning cooking oil or other VOCs and particulates. And then show them a before and after I correct the problem or just re-install their fan and ducting correctly if possible. And show them the difference when you open up a kitchen window or adjacent room window. What happens to the airflow.
Yep, seen plenty of kitchen remodels with a powerful 1000+ cfm commercial hood over their 6+ burner commercial gas range and zero consideration for makeup air. If they have other natural draft combustion water heaters, furnaces, boilers or chimneys, that big fan will try to pull combustion appliance/fireplace gasses back into the house. Problems like THIS is one way to have a very deadly carbon monoxide problem. I’ve seen the plastic fittings coming up out of the tops of water heaters melted from the hot gas getting pulled out of the side of the flue gap.
In commercial construction they know about Makeup Air, in large buildings or commercial kitchens with very high flow exhaust, it’s a must or your air balance will be out of whack (negative building) and it will get pulled in through wherever it can, which is usually aome place not desirable. In residential construction, they don’t worry about this (so many in that business are ignorant of such things), because your standard bath and kitchen hoods (if you even have one) draw so low flow it doesn’t matter, the air needed will pull from gaps and other openings, or just sit there and spin with no actual flow. The standard builder fan is generally a waste of electricity because they don’t have that much pull and lack a feed of replacement air.
Well done sir. This topic is so often skipped and so critical. No perfect solution (I know of) without compromise of added cost (mechanical solutions) and perfect control of conditioned incoming air (this is all unconditioned air coming in). But thankfully we don’t cook all day! Would love to see how your indoor experience compares to these first cost concerns over time!
So the 500-lb elephant in the far corner of that room is: WHAT HAPPENS when that “powered make-up air device” fails? Is there a feedback loop to the exhaust fan that prevents it from turning on? If not, it would seem the “risk” of back-drafting any combustion appliances would immediately return, but be “undetected”……..and potentially start pulling in Carbon Monoxide from various sources. This would seem like a big advantage to using a “passive solution”, rather than a “powered” solution. Electro-mechanical solutions ALWAYS fail eventually……………..well-designed passive solutions, not so much.
I have a correction for your article at 5:24 in the article you say that you need to double or triple the size of the hole. Then you say that you would need a 16″ or 24″. So if you do a little math a 16″ diameter hole is equivalent to 4 8″ diameter holes and a 24″ diameter hole is close to 9 8″ diameter holes. The math for the area of a circle is pie times the radius squared. If you calculate the area of a 8″ circle it is 50.265 square inches a 16″ diameter circle has an area of 201.062 square inches. So in your example you need to have 4 8″ holes to be equivalent. Still good information love your articles. I have learned a lot perusal your articles. I am not a builder just a homeowner who has been a victim of poor building practices many times. I have used what I learn to make my home better. I am an engineer so I love the nerdy details sometimes I think I should have been an architect
Hi. Great article that helps explain the negative pressures that are inadvertantly created inside a building. Whether a residence or a commercial restaurant. Often times I enter a restaurant and need to pull very hard to on the front door to overcome that “vacuum” in the building. As the door is opened I feel the wind blowing in. Or should I say “sucking in”. Commercial kitchen exhaust often times include a fresh air (outside) air make up that is switched on with the exhaust. This unfortunately introduces cold or hot air (depending on the season) behind the chef’s back and neck. Some systems incorporate precooling or heating of the ventilation air. This is expensive to operate and the result is that most chefs or building owners eventually shut off the fresh air make up and let the make up air get sucked in from every available location. Your reference to the 2018 IRC section 1503.6 (makeup air required) is definitely a consideration. Especially the delta pressure limit of 0.01 in w.c. BUT that section is prefaced with the condition of a dwelling containing gas, liquid, or solid fuel burning equip that is NOT equiped with powered draft ventilation. Namely, a naturally aspirated appliance that depends on a chimney with the quintessential barometric draft damper. Naturally aspirated appliances have been the known source of exphyxiation for decades. Many death investigations are attributed to this condition. So in addition to make up systems in buildings, a systematic conversion to power ventilated equipment is essential.
Awesome article learned a lot, just curious how would a remote blower affect the pressure of the house? That’s not so tightly sealed like yours my house is under construction right now but it’s not super tight. I would like to have a remote blower though because a loud hood when you’re trying to cook is the worst. do I need to employ forced air if I don’t have such a tight house?
I don’t think he mentiones it but the active system has also a fan that pushes air in? He said only about the normally closed system which opens and the filter area but not about a fan that pushes air in. Am i geeting it right? Does the speed of the fan of the make up system gets adjusted based on a sensor or is it linked to the hood?
Is there a solution that combines an HRV/ERV capability with make-up air? It seems like not wasting the energy used on air conditioning/heating would be just as important as letting the house not suck make-up air in haphazardly whenever some form of exhaust is needed. I’ve been pondering an HRV retrofit that would tackle my kitchen and bathroom exhausts, and it seems like way too much work. I wonder if new construction designs at least exist that cover it all nicely.
Hi Matt, great article…thank you. Since your MUAS 750 Makeup Air System has a capacity of 750 CFM, what did you use specifically from Fantech on the exhaust side to match up with the FG 8 EC Centrif. Inline Fan for the supply side? Also, what did your (2×8″ diameter?) exterior penetrations involve to work with your tight house? Can you give specifics on the exterior terminations and face plates please? I can’t seem to find the Seiho intake vent – it’s nice and clean looking. My wife and I are just starting the design process for a house in RI. For a Bosch cooktop she is interested in, Bosch recommends a hood of theirs, if we were to buy theirs, that is rated at 600CFM max. So I’m using that as a reference of what we should seek for an alternative system like the Fantech exhaust + MUAS 750 Makeup Air System. Thank you for your time.
I have a problem seing what you did: – 1st: WHY? All you need is passive hatch that opens as needed by flow itself. It is century old way of letting air in or out and open just as needed when needed or gravity closes the thing down. You can still use filter and stuff. It is on attic. You have space to make larger. What when power goes off ?? – 2nd: WHY makeup air is SO TINY, so you make hurricane wind inside and al lot of noise as well. It is much netter to let air from multiple larger spots. Even on LQ PC speakers I can hear hum and fact that you are speaking quite loud and when you pause, hum noise raises up. – 3th: 8 inch hole is NOT big. Behind your back is washing machine door and that would be big hole and ONE would be enough. One big hole is better than 10 small ones! Unless you make honeycomb shape! Circle holes makes a lot of hum.
I am building a house in which I luckily had the opportunity to live temporarily in the same exact model previously. I felt as if the range hood was not vented correctly. The house always stuck of food and felt like much of the air missed the baffle and it was 1000CFM Blower. I have a 48″ gas range myself with a 1000CFM blower. I am doing a flash and batt insulation (2×6 framing) and spray foaming the attic. I’m closed cell from the foundation up to roof rafters. How do I know if I need make up air? Who can I reach out to. I do not have a builder I am running the project myself.
I just open a window or slightly open a door by the kitchen – but if I ever buy/have built another home, then this concept will be on my must have list. My current home has a separate double oven setup, it sure would be nice if those were designed to be outdoor ventilation capable – makes me wish I had a stove in the patio to handle all the multi-hour bake times.
Area increase isn’t linear. The area of 8″ round opening = 50 sq. in. (Pi x radius squared). double that area = 100 sq in, divide by pi (3.14) = 31.8; square root of 31.8 sq.in. = 5.64in. radius x 2 = 11.3 in.; diameter (round up to 12″) diameter makeup opening for 2X passive system. Same calc process for 3 times (result = 13.85 inch diameter; round up to 14″)
Looks like Matt is using a manometer from a blower door system. I’m not familiar with manometers, but after a quick Amazon search I see a lot of options that are geared towards HVAC/furnace work. These seem to all have displays that can show KPa where Matt is reading Pa in his manometer (at least that’s what it looks like). Can anyone recommend a manometer that can measure the kind of levels that Matt is reading in this article?
Awesome article. But lets face it, 99% of homeowners do not have any system close to this. And on the other side, cant afford to do it after the fact either to make things “perfect” There are cheaper old school ways to do this that most people can afford. Is it energy efficient to do so, probably not. But sometimes you can only do what you can do. On another note, how well would this system work in -35 or -40. And the one article you said how tight your house is, and now you need to suck in air every time you cook?
If you’re going to cook inside it’s wise to have some sort of air filtering to capture grease, smoke, food “pollutants” specifically from your cooktop and ovens. But in a high performance house it’s ridiculous to punch two 8″ holes to the outside environment – with ZERO insulation on those thin sheet metal dampers! Seriously, that is just crazy! Imagine the heat loss and air infiltration through those two holes in the middle of winter in Zone 5-7 in North America. And you have that tremendous energy loss 24 hours per day. And if you add some sort of pre-heat to the make-up air you have an additional energy hit (e.g. 5-10 KW electricity demand to run the heater). It’s absurd. Assuming you have an induction cooktop (no more gas), the best solution I can think of is to go with a recirculating hood. Even if they only remove 50% of the “pollutants”, that’s a far better compromise than this uninsulated, gaping hole nonsense. And then open a nearby window for 15 minutes to refresh the kitchen air. Then close the window and you’re back to a super insulated, super air sealed house. Also, notice how high up Matt had to hold that smoke pen, and even then the draw was not particularly impressive. I’m not sure all that much of the pollutants get exhausted even with an exterior exhaust system.
We installed a 1000CFM fan motor for our 60″ hood in our house and I ended up getting a passive system that opens a damper. I’ve never liked it because it isn’t filtered and living here in Austin I worry about all that pollen coming into my house. And as you said it isn’t enough. If I open a window away from the kitchen air really blasts in when I have the vent fan on despite the dampered vent being right in the kitchen. Do you know who in Austin (Georgetown) could install one of these for me? I’m not really impressed with the company my custom builder used as I had to do a lot of effort to get them to figure out the passive system.
These regulations are absurd. It is almost like they want people to have inefficient homes. We know that any draft in a wall cavity completely eliminates the advertised R. value of the wall.. We learned that Fiber batt products are the worst on the market and marginally better than a empty cavity. Cinderblock walls with R Value of 3, insulate better than Fiberglass walls with R- value 16. Real world tests show 1″ of R4 Foam is better than R26 of Fiberglass or Rockwool. It is obvious why every Refrigerator, Cooler, Window unit uses Foam and not fiberglass. The R-Value test is a antique and lazy way to measure performance and does not account for Convection, Radiant heat transfer, humidity or moisture saturation. It is very bias. The fact that 3.5″ of fiberglass meets code, yet 3 inches of foam does not is just stupid. It not even a close comparison. When a thin layer of packaging foam or bubble wrap can out perform fiberglass, there is a serious problem with this industry. And regulations saying your house cant be sealed too tight are BS. Imagine, spending extra money for thicker T-studs, high R-value wool or Rockwool insulation, sealing all of your wall cavities, gluing your sill plate and sheathing, buying high quality windows and doors. Only to have some bureaucrat say you have to cut a hole in your wall because your house is too tight and you require more draft. I think all these regulations are simply to sell more a more expensive home.. They don’t give a crap about your heating and cooling performance or how comfortable your home is.
What bothers me that wouldn’t bother a builder (due to a builders’ unlimited resources) is that even the passive make-up system requires the use of a small motor and a circuit board just to open a flap. And I expect that either of these electric/electronic units will fail. Since within my residence a persistent level of restaurant intensity cooking isn’t taking place but is brief in the need of a full 900 CFM evacuation of one to two times per week. As a result, I’d like to know if a simple make up unit consisting of a flap pulled open by the draw of my range hood would suffice. To me that wouldn’t fail because basically the flap works like the flap in a clothes dryer outlet, but in reverse. And given the make-up inlet was 8″ matching my 8″ duct discharge. Further, I’d prefer the make-up air be ducted to the floor beneath my electric range to minimize a change to the conditioned air within my home, as in adverting the need for a make-up heater. If anyone answers this I’ll be shocked.
He gives much great information for a weather tight home. My ranch house built in 1963 has a full below ground basement. Moisture and radon are a concern. In the winter the forced hot air furnace sucks the basement air into the furnace and out the chimney. The air gaps between the foundation and sill, plus the basement windows provide the needed air exchange . This also removes radon in the winter. In the summer I just open the windows. I am not using any extra electricity. Gas stove and exhaust fan . I do use an air filter system in the spring to remove pollen.
I put a large exhaust fan into a new room I built and the entry door which opens away from the space did not want to open with the fan turned on. I was impressed by that. I’m still trying to figure out a fresh air source for that which isn’t ugly or drips in the winter, so I was glad to find this article.
From Canada have a 70’s rancher that have been constantly/slowly upgrading and recently got to the point that if the dryer and range hood are both running at max it will occasionally snuff out the direct draft gas fireplace insert pilot. (Has thermocouple) So yes make it air tighter but don’t forget to get your fresh air back in.
All these things are awesome and yes they will definitely improve the quality of life in your home. I can’t help but wonder how much power you’re using to run all that, aside from the additional load on your AC system. I am also in Texas in a builder grade home with absolutely no original kitchen ventilation, and that came with a builder grade gas stove.
This is a big area where commercial kitchens have a clear lead. The hoods are much bigger, allowing for a larger capture area. Makeup air matches the required exhaust rate and either comes down directly in front of the hood or slowly passes through the kitchen from the opposite side allowing for better fume capture. Sometimes the air coming down in front of the hood is cooled to keep the cooks comfortable. Or, with the latest tech, all of the air is cooled or heated to keep the whole kitchen comfortable.
Is cold air blowing onto your dining room table? Couldn’t your make up air supply be in the kitchen where people aren’t sitting? I don’t have a make up air solution in my house. My hood is 700 CFM and then I have two exhaust vents in the kitchen ceiling that are ducted to a 1000 CFM blower. Normally, the hood alone with no windows open works well enough. If I open a kitchen window about 4 feet from the stove, it creates a draft that remove the heat from the pan. If I flip a greasy steak on the char broiler and create a huge flame and smoke, I’ll need to turn on the ceiling system and open the sliding glass door near by. It works well, I’ve never set off the smoke detector, but it is sort of a ghetto solution.
You completely missed the reason that the fan is above the stove. In case of a fire, the fan above the stove, compresses the flame, making it hotter. Then when it exhausts the air into a large duct, it causes the pressure drop causes the flame to extinguish. With your configuration, you will have a flame thrower running through your ducting, which may burn your house down, and cause injury or loss of life.
Matt Should I put the make up air supply as close to possible vent as possible? High or low (ceiling or Toe kick?) Seems like putting it across the room pulls a significantly greater amount of conditioned air out of the house. Also, I need make up air for the dryer and bath fans. I will be using an ERV exhaust in the bath areas on our first floor but most likely exhaust fans on the lower level. Thoughts?
Just had my 40+ year old house renovated with new window, roofing & siding. All of a sudden my CO detectors started going off on a regular basis. Due to the house being so much tighter, it was sucking in utility exhaust fumes. I installed a makeup air duct direct from the outside to the suction side of my forced air gas furnace. Now makeup air automatically gets sucked in under power whenever the furnace kicks in. Huge difference! The kitchen is all electric and I don’t do alot of cooking, so little makeup air needed there. My utility bills have not shown any measurable increase since setting up this system.
Wouldn’t it be better to have the makup air come in right by the exhaust so that you aren’t throwing all your conditioned air out? That way the unconditioned makeup air is getting pulled right out with the fumes. It seems like with how you have it set up you are exhausting all of your conditioned air between the hood and the makeup. There isn’t any reason to do that.
Great job Matt as many contractors m8ss this.. I think you need to study on the energy effectiveness of this though. As others have pointed out replacement air should be conditioned. There are so many sources of exhaust fans in a home (bathrooms, laundry room, etc) that a cost effective solution needs to be part of the HVAC system and introduced near the exhaust locations.
Why dump make-up air on the opposite side of the house. Let’s totally disrupt HVAC air paths whenever you use the hood, and have a huge breeze across the whole house. Make-up air should be dumped along the front edge of the hood youtube.com/watch?v=RJ-WF7gaiXA where it is almost immediately exhausted, or as close as possible . Matt has done this too before.
If you think about it, it makes sense that with an 8″ passive hole, there is such a pressure difference. If there wasn’t a pressure difference, the air wouldn’t be pushed in through the hole. Since the exhaust vent is pushing so much air out, there has to be enough pressure difference so that the air is made up. It reaches equilibrium.
In Europe (Spain) most homes use induction and, in passive houses, recirculation extraction hoods. That ensures that there aren’t combustion gases or smells, while keeping air tightness and thermal performance, since all air is controlled by the heat exchanger. Direct exhaust outside the house’s envelope would be considered a mistake in terms of energy usage. The downside is that these hoods require more frecuent maintenance (filter replacement or cleaning) depending on model.
Don’t like the idea of around 1000 CFM of unconditioned hot/humid air entering my house while cooking. Came across a makeup air kit using a 10″ motorized damper with static pressure control switch activated by Venthood airflow. The fresh air intake is ducted into HVAC return plenum with the motorized damper. Whenever the hood comes on, the pressure switch activates HVAC system fan, outside air passes through the HVAC filter and is distributed through existing ducts. Since it’s blended with indoor air, it would be partially conditioned and if the indoor temperature rises above setpoint, the house thermostat activates cooling. This would work the same way in a heating season. I can see several advantages of doing it this way, interested in hearing of anyone has any experience doing this way or expert opinions. Imperial Kitchen Ventilation company makes such a kit, product is MA10 (they also make 8 and 6″ versions). Appreciate any input.
So this is all new to me, but have been perusal a ton of articles as we are going to be building our retirement home in the next year and I like the concept. That being said the more I watch and read there seems to be lots of potential cons to this type of construction. Sure there are lots of pros as well, but just looking at this one area of make-up air when it comes to all the bathroom vent fans, clothes dryer, vent hood etc. and the potential of your home becoming a death trap if part of this system fails is concerning. I’m really not trying to be a Nah sayer because I love the concept, but I’m not really finding a lot of answers to the cons. This is a great article explaining the issue and how Matt resolved it, but it would be great to see a follow-up article addressing the concerns/questions that several people have commented on. I live in Houston Texas and it gets extremely hot and humid in the summer the idea of sucking hot humid air into the house to balance it makes me question the logic of building these super tight homes that need all these workarounds vs doing a more traditional build and perhaps just doing a better job of insulating. I know there are a lot of smart people in this area, but a lot of this building type still seems to be a trial-and-error approach that is trying to work out all the bugs. My current home has several powered dampers in the HVAC system to balance air temps around the home. I have had to replace several of these over the years and they still get stuck open or closed or partially opened.
Instead of a pre-heater, what about a heat exchanger? Wouldn’t this be more cost effective from energy costs? I think you would need to have either a common exhaust with a common make up, or one HX+makup at each each kitchen, bathroom ect… I would love to rebuild or at least modernize my house, but at the end of the day, my taxes will go up as much or more than the energy savings, on top of the $40-60k cost of upgrading. This tech is also advancing fairly quickly. The cost and benefits have improved greatly since I started designing a passive home years ago.
Good basic article. Nice house BTW. So, please tell me how your newly installed MUA sytm, will work when peak demand is needed. Example: – Dryer is going – Cooking vent is going – gas HWH just lit up – furnace fired also – I went into the powder room to burn a mule, vent is on All this draw, even though two high efficiency appliances have their own MUA, please tell me if I need a hole in the side of my house to drive through. Thankx.
Matt, it is interesting to hear you mention that the make up air system you are using contains a MERV 10 filter. Weren’t you very intentional with installing a premium filtration system on your ERV, MERV 16 I believe? Now you have 400 CFM of MERV 10 air entering your home when cooking? Additionally, the air in not conditioned. Both from a heat stand point and humidity stand point. I personally would have added the heating element on the make up air system. Austin may not get as cold as Michigan, but it is completely normal for Austin to be in the 30s F, or even high 20s F in the winter. I am not criticizing you, just raising the point.
For anyone considering this, ask your HVAC guy or anyone knowledgeable with the psychrometric chart. Let’s say your indoor air is 72 degrees. Bringing in unconditioned outside air with a dew point greater than 72 degrees guarantees condensation. Examples would outside air higher than 72 degrees and raining, 85 degrees outside and relative humidity above 65% or 95 degrees outside and a relative humidity above 50%. It will be raining in your house! The same problem occurs with ERVs. The heat exchanger can cool outside air below its dew point, resulting in condensation. A ventilating dehumidifier would be a better choice for humid climates.
i have seen the ever increasing profit driven sale of excessive cfm kitchen cooktop exhaust fans for 20yrs. Do a little research, council your customer, Shepard your designers-archi’s, increase the capture area and consider a nice quiet 300-350cfm motor. i have built dozens of restaurants in Seattle with Hoods/Make-Up -HRV/ Ansel Fire as well as Curtain wall chilled air as make-up along the Sautè line. Giant cfm is just another ‘look at me’ feature that guarantees a cascading scope creep event in modern design build. more isn’t always better it can just be more.
I would think if you lower the hood and make the hood a size larger then the cook top it would capture dirty cooking gasses in the air more efficiently. This would reduce the make up air required. Then simply open then window above the sink. Windows in the kitchen should be above the sink. Not far from the stove. A two burner design with both burners located under the center line of the hood will create more head room. For example, If the range is 30″ a 36″ hood would be best. A 24″ cook top would use a 30″ hood.
This is I’m sure a stupid question, but I don’t know was just wondering- so if you have a fresh air system for your whole house -like Clean Aire 70H with dehumidifier-would that not be enough fresh air? Another question was the make up air needed on a 400CFM or on a vent that is higher than 400CFM? Cause the vent I am looking at is 400CFM.
Hi Matt, Thank you for your article! I’m searching for makeup air solution then your article pop up. I’m going to have a 1200CFM hood so makeup air is a sure thing I need. I plan to put the register in mud room but thinking I may just put it in the basement mechanical room. Is it OK? Or the makeup air better to be in the same level? Thank You again!
1 atmosphere, normal air pressure, is about 100,000 pascals. The code is less than a 3 Pa difference? That seems like serious overkill. I have to have the pressure inside and out equal to within 0.3%. Is this the code for extra tight houses? Is that even a separate category? I’m guessing not. Compared to my house built in the 60’s, this seems like a drastic overreach in the building code.
Cool article. I wish you could have shown a diagram of the whole ducting. I understand you’re adding air (makeup) to equalize the in vs out, but confused where the makeup inlet is in relation to the kitchen exhaust vent. Also adding a 2nd 8″ hole isn’t the same as increasing the diameter from 8″ to 16″, because of the exponential relationship of a circles radius to the area, you would have needed 4x 8″ holes to equal the area of 1x 16″ hole
Great articles Matt! Learning a lot as I’m in the process of a new home construction as well. I’ve been thinkitng about this make up air system for a while and was hoping I could find a way to trigger the Aprilaire ventilating dehumidifier for the ventilation mode when fans are running. From a home automation perspective there are several ways I can determine when fans are running and the cumulative CFM draw down on the house, however, while the Aprilaire ventilating dehumidifier pairs nice with the HVAC and Ecobee for humidity control all I’ve been able to determine (including speaking with some very knowledgable folks in Aprilaire tech support) is that the ventilation feature runs on a simple minutes of air per day controller and can’t be triggered by any external protocol or relay. I’d be really interested if anyone has gone down this path and figured out a way to do it. The Fan-Tech stuff looks like it might accept external triggers which I’ll pursue but I’d like to use the upgrades I’ve already committed to instead of buying more equipment. Plus the ventilating featon ure on the Aprilarie already has a filter and dehumification capability which for a Florida home would be nicer than just bringing in hot humid air to balance the kitchen and other fans.
Great job! Wish I could go as far as you did. $$$. Tightened up our 1980 house, but was told to go no further unless spend a lot more on HVAC. A lot of our make up air actually comes from the wood stove we tend to only use in power outage or severe cold. If we use the wood stove, a window is always left open. Not enough leakage in our house.
Interesting stuff. I’m gonna assume the reason there’s such a difference in pressure is because you’re using a powered exhaust vs passive intake. The powered exhaust will simply try to draw more air in than the current opening(s) can pass. I need to add an exhaust system in my kitchen to help remove all the grease from stovetop cooking. My non exhausting hood vent just ain’t cutting it. lol With my current setup I can go up across the kitchen(2 story home with plumbing above kitchen) and out the side of the house fairly easily. Just not sure I can use large enough ducts.
I like this. It’s nice to see it’s already a package deal so I don’t have to build one which is what I was thinking! The only thing I don’t agree with would be your location of the make-up air on the other side of the house which means you have to create an air flow across the entire house to evacuate food smells or smoke or steam at the induction stove top. It seems like it would make much more sense to have the make-up air come in locally in the kitchen so that you don’t suck expensive conditioned air out of the house. I have often thought there should be make-up air somewhere in a bathroom at the floor level so that when you want the fan on in the bathroom it would suck out just the air in the bathroom. Not to be too graphic but if you have a stinky bathroom there’s no reason to suck the air out of the rest of the house just because the bathroom has an unpleasant odor just refreshed the air in the bathroom! This would be the same for your kitchen. Better luck on your next build.
I have a house that I am designing in North Texas. The house will have a gas cooktop and a wall mount kitchen hood that will pull 1266 CFM at its max setpoint. Fantech makes a matching make-up air fan for this set up (similar to your install). I fear locating the make-up air at the hood for 2 reasons. 1. It will blow 1266 CFM of hot air on to the person cooking. 2. Since it is forced air, 1266 CFM will be blowing onto the gas burners and pots (possibly altering the cooking process). I saw how turbulent the air was at the make-up grille at the other end of the room of your home. I like locating the make-up air away, like that to make the conditions at the cook-top optimal. Unfortunately, the HVAC system will somehow have to manage the addition of 1266 CFM of outside make up air when the air is introduced so far away from the hood. The energy efficiency / reduced HVAC tonnage for tight construction home might need to be recalculated to account for the 1266 CFM of outside air. Therefore the HVAC system has to be upsized to account for this. Frustrating.
Well for me in my home I open the deck slider 4 feet from my gas stove to let in “make up air” as my cheap microwave squirrel cage fan does nothing to exhaust the smoke and combustion gas from cooking. I’m looking to add a 6″ powered fan hooked up to the fan controller in the microwave hood but that’s all I can do. Mostly make it actually exhaust the air up the 6″ diameter pipe that goes through to the roof. Not gonna give up my gas stove as I don’t have 20K to rewire the house for Electric stove. Show me all the SE Asian restaurants switching from the high volume gas burners (wok cooking) with successful induction cooktops and I’ll look into it. I think the governments should stay out of our business in how we want to cook and heat. Natural gas is a byproduct of oil extraction and that isn’t going to stop. You knew younger people can eat electric all you want. Leaves more gas for me and the others that agree.
Great information regarding makeup air systems, Matt. You noted a heater option for colder climates to temper the incoming makeup air, my question is, you live in Texas, where it gets hot and sticky in the summer… a lot of relative humidity. It appears you have lived in your new home for about a year now, how much hot, sticky air where you pumping into your home this past summer while using this system? I didn’t see the option of a pre-conditioner to temper the make-up air to help reduce both temperature and relative humidity. I would think this would become an issue when cooking for long periods of time (say cooking for a 4th of July celebration) and the exhaust fan is on for 20-30 minutes, resulting in the makeup air unit being on for the same amount of time. Either one, your home’s air-conditioning system had to work overtime, trying to condition the 400 cfm of non-tempered makeup air being pumped into the home (and 400cfm is nothing to sneeze at) and/or you were dealing with high air temperature and humidity being pumped into the home, or both. I reviewed the Fantech website and I did not see the option for a tempering unit which could reduce the incoming air temperature and humidity. Curious to know if you had any issues over this past summer?
I’m someone who works with airflow and pressure differentials at my work. Mostly to keep things clean and also to keep from having the place explode. So I get it. I also get the idea of controlling the air flow. But I live in a 100+ year old house. It’s so silly. All the regulations trying to stop every tiny little leak. Insulate to insane levels in the north east. Then limit what fuel we can run our houses on. Then we need to have higher cfm exhaust than years back. Now we have to bring in outside air. Why is it so terrible to have an old leaky house again? My pm2.5 and other PM s are lower than some relatives are with much newer homes. And I have several cats and two old world dusty parrots. Chasing out tails I think we are. I believe we passed the point of reasonable return a decade or two ago with many of the new things that are now required. Actualy these systems are super important to keep in mind as you gradually update an old home. I know one realitice that replaced slider and storm windows with new windows. The house was already much tighter than mine but still an uninsulated 1960s house. you can smell a small cooked meal well into the next day and if anyone has showered reciently. Never had this before the windows. The bath has a up to code fan but nothing in kitchen. Males me afraid to tighten up the building envelope too much on my old home.
You’ve gone for just about the most complicated system, with a remote fan above the exhaust, and a remote make up air system a long way off. And they come on and off at the same time, so connected electrically with long circuit run between the two? Meanwhile you have an exterior wall just adjacent. Why not a hood system with a fresh air intake and exhaust built into the same unit? Your cooktop exhaust is more complicated than my entire home HVAC system (a ductless mini-split).
A clue on duct sizing for folks remodeling… look at any industrial centrifugal pump: inlet is typically larger than discharge side. The reason is a little different (preventing cavitation) but the principle with air functions about the same. Atmosperic pressure is roughly 100k pascals – that’s your precharge to the inlet. Output pressure off a fan is an amplification of that – never equal/always more:. So, if in/out ducts are equal size, the fan will take volume from somewhere else trying to reach its design output.
Great info… but, one of those luxury items few could afford.. of course I’m in Toronto which currently has one of the worst cost of living problems in the world. 1500 sqft basic townhouse runs about a million bucks right now, so the kitchen window make up air is going to win 99% of the preferred solutions here…
I’m bidding a 36″ powered range hood install to vent 6’ away to outside through the upper cabinet soffit. Customer has an old JennAir down draft induction cooktop that they want to replace with a new ventless model. In a pinch, could I repurpose the old under counter duct as a make up air source? Maybe run to a stealthy black vent in the toe kick?
On my recent parents house remodel I installed the thermador exhaust setup with remote blower, the MUAH 10″ heater and the Merv 13 filter for the make up air in SE Michigan. To be honest they dont use the heater that much. After about 3 months the filter was in rough shape, folded over and covered what looked to be mold. anyone have a idea of what i did wrong or didnt do enough of? thanks
What about bathroom exhaust fans? Are they linked to the make up air too? How does make up air operate if a door is closed? I’d assume it would just go under the crack between the floor and the door, but wouldn’t the suction of the bathroom vent fan be impacted by the resistance? There’s definitely not 8-16″ of clearance through doors.
In Spokane, I would have a filtered and heated make up air system in winter but in summer, we always of late have 8+ fires around us that settle into our basin, AQI is extremely hazardous at times so must have a HEPA filtration system to prevent bad air from coming into house in July thru mid September. It’s a problem I need a Registered Professional Engineer to address as this is beyond my skill level. Be helpful in several western States and BC would do fire mitigation to rid underbrush that flames up but no one in department of interior has thought of that.
I’m curious about the placement of the make-up air vent. Wouldn’t it be better to have the make-up air vent to be closer to the hood so you don’t exhaust out as much heat/AC-air from your entire room? Now it seems to be creating air currents throughout your entire living room pulling the heat away. I have no experience in this field so please school me 😃
What is not mentioned in this article is the cost of making up air. In my recent experience of remodeling the kitchen, the quoted cost of a make up system that ties into the HVAC system is $5k. That is a cost that is not discussed in budget planning. What would be an estimate of the system Matt describes in this article?
Build an airtight home then vent air in from outside that needs to be heated so you don’t get Co2 poisoning… by code… Not “trolling” here🤔 but… insulated can lights had a dual purpose after all! Just seems redundant from Laymans terms… A fan out, a fan in and a heater to accomplish what an error in design did inthe can lights
So on a January morning in Chicago I wake up to make some scrambled eggs and turn on my stove hood and in comes 0 degree air across the room so the smoke and odors flow up and out the house more efficiently. Not for me brother. My hood has served me well for 20 years and this is big time overkill. FYI that power make up air retro fitted in new or old is 3-5 K !
A 16 inch diameter passive duct I think would be bigger than you need. Your fan powered 8 inch outlet duct has a cross section area of about 50 square inches. A 16 inch diameter duct has a cross sectional area of about 200 square inches. If you are wanting to double the cross sectional area of your passive makeup air duct then you do not want to double the diameter of the outlet duct. Doubling the diameter of the passive duct to 16 inches actually quadruples the cross sectional area of the of the 8 inch outlet duct. If your need is to double the cross sectional area of that 8 inch duct, then you will would need a passive makeup air duct that is about 11.25 inches in diameter. I would start with a 12 inch passive makeup air duct opening and do some testing to see if your inside/outside pressure differential is within the 3 pascal limit with the exhaust fan running and the passive inlet duct fully open. Perhaps you would need to go to a bigger inlet air opening if you are not getting an acceptable pressure differential. With a house as tight as yours you might have to take an exterior door off the hinges to get enough makeup air!
You wouldnt believe how many attics ive been in that has a fresh air intake with a heat exchanger and it was never wired to power. Probly 80%. Definitely some crooked hvac companies doing big housing projects. The biggest benefit to me for induction stovetops is how easy they are to clean. That alone makes it worth it
We ran into this a lot in central Florida … when they started building home too tight we had to introduce fresh air. The problem is just pulling in outside air at 96 degrees and 99% rh caused a huge issue so instead of installing a 3500 kit from Trane I wired the damper to the compressor circuit and ducted it straight into the return air box now I’m perusal this and I’m wondering how I could do something similar to the exhaust I don’t live in Florida now but in a more forgiving climate but I like the concept good job Matt ….oh we call that a magnahelic to measure those air pressures a manometer we use to measure gas pressures like propane or natural gas
I’ve got a kitchen exhaust fan, an electric dryer, 3 bathroom fans, a gas water heater, and 2 fireplaces. Why not have a makeup air system that responds automatically to the atmospheric pressure difference? The other is a need for air cooling as well as air heating in the makeup air system. Aren’t there benefits to not sucking air through carpet or a garage benefits in older homes?
People need to do the meat and grease cooking outside. The 300 CFM fan is adequate for an electric cooktop and general cooking. These makeup air rules are an example of why it keeps costing more and more to build a home. Most houses are not that tight and the real safety issue is with gas appliances. Go all electric and 300cfm exhaust.