To ensure a healthy and balanced attic, divide your square footage by 300 sq. ft. and round up to ensure you’re getting enough ventilation. Section R408.1 specifies that the crawl space (under-floor space) must have ventilation. Owens Corning Roofing can help you calculate the number of vents needed for a healthy and balanced attic using their 4-step ventilation calculator. Follow the 1/300 rule: 1 square foot of ventilation per 300 sq. ft. of attic space.
To calculate the number of roof vents required, use the Roof Tile Vent Calculator, which calculates the 2015 International Residential Building Code MINIMUM (IRC Section R806 – Roof Ventilation 1), which states 1 square foot of Net Free Area for every 150 sq. feet. The general rule of thumb is roughly one vent per every 300 sq. feet of attic area if the attic has a vapor barrier. If not, there should be one vent for every 150 sq. feet. Consult a HVAC engineer for the exact needs of your house.
The number of air vents a house needs typically depends on its size and the number of floors. One per room is ideal, but placing two or three in larger rooms or walls with multiple exterior walls requires multiple supply vents. The plasterer recommended installing external wall vents to improve air circulation and prevent moisture holding in cavities. A good rule of thumb is to have one return vent for every 100 to 150 sq. feet. It costs $200 to $500 to add a return air vent. If each space is served by a separate system, the required outdoor ventilation rate of each system is 150 cfm and 750 cfm, respectively.
📹 What Are These Vents For Above The Doors
Back in the day most homes that were built with a central heating and air conditioning system had a ductwork design with a supply …
What is the rule for roof vents?
The 1/150 ventilation rule is a universally accepted guideline for roof ventilation, requiring at least one square foot of ventilation for every 150 square feet of attic or crawl space. A minimum of 13. 3 square feet is needed for a 2, 000-square-foot attic. The optimal ventilation depends on factors like weather, roof style, and local construction regulations. Popular ventilation methods include ridge vents, soffit vents, gable vents, and turbine vents.
Ridge vents allow hot air to escape, soffit vents draw cool air, gable vents allow hot air to escape, and turbine vents draw heated air from the attic using wind force. Further ventilation may be needed depending on other factors.
Can you have too many vents in your house?
The article discusses the importance of proper roof ventilation in maintaining a home’s resilience, comfort, and energy efficiency. It emphasizes that excessive ventilation can lead to condensation buildup and mold growth in the attic, reducing the home’s lifespan. The article suggests that the right amount of ventilation depends on factors such as roof type, local weather, and budget. It also discusses common misconceptions about the benefits of excessive ventilation and the importance of considering factors such as roof type, weather conditions, and budget before installing vents. The article emphasizes the need for a balanced approach to roof ventilation to ensure optimal performance.
How many true vents do I need?
To properly ventilate an attic, it is recommended to add one vent per every 300 square feet of attic area if it has a vapor barrier. If not, one vent should be added for every 150 square feet. For a 450 square foot attic, 3 square feet of vent space should be needed, evenly distributed between inlet and outlet vents. The net free area (NFA) rating should be used to determine the space each vent covers.
If the roof has a slope greater than 6:12, there will be more volume in the attic than the actual square footage, so more vents are needed than 1 per 150 square feet. For more information or roofing services, contact 1-800-HANSONS for a free estimate.
How many vents should a 1200 sq ft house have?
The general guideline for homeowners is to have one square foot of roof vent for every 300 square feet of ceiling space, if your home has a vapor barrier, or 1:300. If not, one square foot should be installed for every 150 square feet, or 1:150. The vents should be split evenly, with half dedicated to air intake and half dedicated to air exhaust. For example, a 2, 400-square-foot home with a moisture barrier would need 8 square feet of roof vent.
However, every home and climate requires a different plan for roof vents. Different types of vents are recommended and installed for different homes, and it is essential to assess your specific needs and requirements to ensure the best possible ventilation system.
Do houses still need air vents?
New construction and airtight homes are designed to limit air infiltration, resulting in energy savings but requiring minimal ventilation unless a window or door is opened. Mechanical ventilation is crucial for these homes, as it ensures efficient ventilation without causing stale air. A lack of ventilation is a costly disadvantage of airtight construction.
When pursuing weatherization or air sealing, it is essential to upgrade to mechanical ventilation. Basements, attics, and crawl spaces often have holes and cracks that allow air infiltration, while older homes often have gaps around windows and doors. Sealing these areas can help prevent air infiltration and make homes more airtight. Therefore, when pursuing weatherization efforts and tightening the building envelope, it is essential to upgrade to a mechanical ventilation system simultaneously.
What is the formula for calculating vents?
The ventilation rate is a crucial factor in determining the amount of fresh air supplied to a room per hour. It is calculated by dividing the room’s volume by the ventilation rate, which is typically expressed as m3/hour or cfm. For livestock, authorities or the government determine the amount of fresh air to be supplied and dirty air removed per live animal weight per hour. This information can be used to calculate the total amount of ventilation, which can be calculated using the formula: number of animals x weight per animal in kg x desired amount of air per kg per hour = m3/hour.
How do you calculate the number of roof vents required?
Local building codes typically mandate compliance with either the 1/150 method or the 1/300 method exception, which dictates one square foot of ventilation for every 150 or 300 square feet of attic floor space, respectively. It is of the utmost importance to ascertain compliance at the local governing level prior to calculating or installing products.
Do you need an air vent in every room?
Building regulations mandate mechanical ventilation in bathrooms, kitchens, and WCs, as well as utility rooms with washing machines or tumble dryers. Without an extractor fan in the bathroom, condensation can lead to unsightly damp and mould patches. Bathroom extractor fans should be mounted on an external wall close to the ceiling, and their power should be at least 15 liters of air per second when in use. Most homes have bathroom extractor fans on the same electrical circuit as lights, operating simultaneously.
Models like the EnviroVent Cyclone 7 feature a moisture sensor that detects water vapor in the air and adjusts power accordingly, making them more energy-efficient. The power required for these fans depends on the size of the room and the room’s size.
Is it bad to sleep in a room with no vent?
Poorly ventilated bedrooms can lead to increased levels of carbon dioxide, which can make you uncomfortable and potentially harm your health. Research shows that concentrations of carbon dioxide during sleep are 3 to 5 times higher in bedrooms with closed windows. Opening windows or using fans can freshen the air, making it easier to fall asleep. Proper ventilation can also help individuals feel better rested and more alert after a night’s sleep. Carbon dioxide is also linked to conditions like sleep apnea, as it triggers neurons that can rouse you from sleep.
How many air vents should a house have?
HVAC contractors typically use a rule of thumb to determine the number of air vents needed for a standard residential HVAC unit. For example, one supply vent and one return vent should be required for every 100 to 150 square feet of living space. The HVAC system circulates air throughout the home, maintaining a comfortable indoor temperature and healthy air quality. This circulation is achieved through a network of ducts that connect to supply and return vents in each room. Ductwork, a network of pipes or conduits, serves as a passageway for air to flow from the central heating or cooling unit to various rooms in the house.
How do you calculate the number of vents per room?
The number of vents needed per room depends on the square footage of the room, with larger rooms needing at least two vents, and smaller rooms needing only one. To determine the number of vents, divide the number in a room by the square footage of that room and record the result for all rooms. This formula will help determine the exact number of vents needed in all rooms. It is important to clean out vents every other year to avoid unnecessary AC repair costs. The rule of thumb is to divide the number of vents in a room by the square footage of that room.
📹 Understanding Roof Ventilation & Venting Options (Ridge, whirlybird & Box Vents)
Understanding Roof Ventilation & Venting Options (Ridge, whirlybird & Box Vents) When it comes to roof venting and ventilation …
Hello, thank you for this article. My house was built in 1992, and believe me, the contractors cut corners. I have one return vent in the entire 1456 Sqft, two-story house. I’d like to add these vents above the doors to remove/circulate the excessive heat from the second floor. Do you believe these vents will do so when the HVAC system is running? Thank you.
Do they help the airflow when the door is open too? The temperature in my bedroom is much different than the rest of the house and I generally know why, it’s on the opposite side of the house and two floors up from the blower so the airflow is quite low. There’s a return just outside the bedroom in the wall, close to the floor. I can imagine having a vent above the door would help some, particularly in the summer.
Bedrooms doors stay shut because of pets. Which makes the rooms uncomfortably warm. Our home doesn’t have these vents. Could they be added over the door. Not sure if there’s a header over the passage. Plan B would be to vent the door. But was hoping to upgrade our ugly doors in the future. And a wall vent would be a permanent solution.
I have one of these that isn’t above a door but to the right of it in my families media room. There’s nothing inbetween the returns either. There are two supply vents that are along the same wall of the room. I feel the room has difficult to keep cool and it stay’s approximately 2 degrees warmer at least than the rest of the house. What could possibly be done to improve things in that room? Any advice will help, BJ.
This seems pretty counterintuitive if you have rooms that aren’t usually being used. I would actually want to close all ventilation to those rooms so they aren’t being heated or cooled for no reason. I’m buying a 3 bedroom house for myself and may or may not rent a room out. I just learned there are buffers you can add inside the gap at least to deaden sound more. I’ll have to install some of those in my new house if they don’t come installed already.
The ridge vent / soffit vent idea is great in normal temperature areas, but on the Texas Gulf Coast at 108 F -118 F Heat index that’s a 104 F outside air temp. with a 81 F Dew point and with no rain for 2.5 Months my attic is definitely a HOT ATTIC no doubt, the upstairs A/C run’s constantly from noon to 6 p.m. and sometimes can’t hit the thermostat set point and yes my attic is very well insulated ! So, I am looking at doing a continuous soffit vent going forward !
I sold roofing materials for 9 yrs and had a bonded licensed contractor I worked with have his crew replace our roof and add ridge vent system cora-vent, which we highly recommended to all home owners. I went into our attic to see the underside installation, knowing I would see the sheeting cut back to allow the system to ventilate… they didn’t cut out the ridge sheeting at all!! They just put the vent system on the closed ridge😮 of course I thru a fit and they had to come out and correct the situation. Always check contractor work at every step…. improper installations void warranties…
Hoping you can help me, I was recommended 2 attic fans on my hot attic. They were installed and have not made a difference. Now I realize that by looking at them closer, they are Power Vents. What do you recommend I do? I have not paid yet as they were leaking as well. I live on a military pension and could really use your help.
i disagree with electric fans in the attic. yes you can pull air from subflooring such as crawlspaces or basements, but the vaccuum has to be so intense it overpowers the attics static pressure. if you exceeed the attics then yes youll be breathing moldy or stank air. but if you match it properly it wont do anything but cool the attic.
I’ve been slowly converting a shed into a tiny house and all this ventilation stuff has stumped me throughout the process. It’s a metal building with no original ventilation – no soffits or anything. I original closed cell spray foamed the whole thing sans underneath thinking that would be enough for insulation (no experience prior to this). After some harsh winters, I started going over all the sprayfoam with rockwool. There’s been some things that I’ve become aware of while doing this (I should’ve noticed sooner but I never bothered to investigate or research). There’s always been a sort of musty smell in there, and occasionally I’d notice the carpet would be moist which I assumed was a hole in the roof or something. There’s no attic; and one loft. As I’ve been installing the insulation and can spray foaming any nook & cranny I come across, I noticed the whole underside of the roof (on top of spray foam) was moist. This has made me hesitant about continuing, and I fear the parts I’ve already completed and sealed off are rotting away. I have cleaned off some mold that only seems to go after wood, and now I’m started to go over the original studs with mold killing primer before putting up insulation. This part of the process has been completely over my head. To me it’s always seemed counterintuitive to add fans and vents when you’re trying to heat/cool a place. (Also, I don’t have a proper hvac setup. Just a wind unit, and a plug in the wall oil heater for winter.) I’m starting to realize how important is.
You buy the smallest Power Vent they make and you wont have any moisture because the air is moving and is being removed. Adding a power vent is like adding 1/2 ton to your AC unit which was told to me by the manufacturer and it works. I had the roof replaced and they wanted to add a ridge vent I refused and installed a Power unit and works great.
Thank you for this article! I have multiple leaks in my just turned 7 year old roof. It happens during incredibly heave and long lasting rains. The guys who installed the roof are saying that improper ventilation is causing the leaks. They came over about a year ago and I fixed a few of the issues, I thought. The bathroom was venting into the attic, I now have it venting outside. The gable vent was not working, and now it is. I have a 1600sqft. house and the gable vent is rated for that. It is stucco with the large overhangs that have no wear to put soffit vents. The only place that is allowing air to enter is another part of the attic that also had a gable vent which is no longer working. The GAF rep came out and basically said I needed to put in a power vent. You say no to those. I am pretty confused about what I actually need to do. Should I order some of the 4 inch vents and add them along the edge somewhere and keep the gable vent? I’m pretty sure that I have a leaking roof which is causing moisture issues. And not the other way around, but I am not a roofer. The ventilation for the attic was fine until this roof went on. Can a synthetic underlayment cause problems? Do you have any tips or suggestions for how I should proceed? There is old insulation in the attic, might updating that help?
I have a 3,189 sq/ft home (2 story) in FL with 4 vents on high points… I am building an attic space for utility room (hanging 2 air handlers). I am using 2 X 6 beams supporting truss beams, so it lowers the interior room ceiling allowing cavities for airflow. I am also sealing ALL holes vent pipes, electrical boxes, attic access, everything, and spray foaming to seal utility room walls and ceilings between attic. Now my question is, since I have attic vents, which are currently 12″ X 24″ cutouts which I am looking to replace as the heat is sometimes 130° up there and no way adequate… What can I do in this case as I was considering several Solar Attic fans throughout or spray foam the entire roof decking, baffels, spray in insulation (currently present) to make it an entirely conditioned space as mentioned in another comment… if thats the case do I need the vents, fans, etc… ?
They put a major hiway behind our house. Older house and my brother had a bathroom fan exhaust but the hiway noise was top extreme and he closed it years ago. Also there is no Soffit or any ventilation to pull air in. Major dampness issue. Is there any way to reinstall the bathroom and or kitchen vents that would not allow the hiway noise in thru it? Regards, Catherine
Thank you for this clear explanation of attic ventilation. A few years ago after a bad storm I had to replace roofs on a 20 year old house with a hip roof & on a very old farm house. The roofer put whirlybirds on the farm house & doubled the box vents on the newer house & he replaced the power vent but did not hook it up to power. I didn’t like that he put in the whirlybirds & didn’t have the power vent hooked up to power. Now I understand he probably had the same ideas you do about vents & I feel much better now about what they did at my houses. I already had venting the entire distance of the soffits all around the newer house.
We have a large home built in late 70’s main vents are gable vents large triangle vents at each end, with whirlybird 2 in the roof. So I was thinking of add 2 electric fans at one end or changing the whirlybirds to solar fans to help cool the attic on really hot Texas summer days. I have no soffit vents and no ridge vents. And our insulation is really good – batts rolled in and blown in covering all the batts about 6″-8″. 3700 sq foot house
Isn’t a power vent the same function as a whirlybird? They both pull air from the home. I live in a 5 unit brownstone, with each unit being 900 square feet (83.61 m²). On the flat roof, there are 8 whirlybirds, with 4 clustered together from the other 4, about 15 feet (4.57 meters) apart on the same side of the roof. They are no longer spinning and need to be replaced badly, as I am getting a lot of water coming in to the building. I was thinking of replacing each cluster with 1 solar turbine, by building an elevated enclosure over the opening, and sitting the solar turbine on top of it, since the solar turbines moves much more air. Do you think that is a good idea? Furthermore, the whirly birds are over 4 feet (1.22 meters) tall, and they are right up against the parapet, which needs to be repaired, but cannot be accessed because of the whirlybirds. Thank you, for this most informative article.
I need to add shingle over edge vents, ( no eve to add soffit vents) 4 sections 7feet 6 inch across 16 feet wall to ridge…can i use a whirlly bird for each of the 4 sections….house 50 yrs old vaulted ceiling no trusses ….dropping ceiling inside 8 inches adding 6 inches of rock wool insulation w 2 inch air gap
Great article! Would still like a better option for hip roofs with basically no ridges for ridge vents. Whirly birds dont seem like a legit option since they appear to only allow for real air flow between the say 24″ width of the 2×4 of the roof decking where it is installed. Any suggestions for hip roofs?
Thanks for the great info, I’ve been looking for an informative article like this! I have a quick question or two that hopefully you can answer. I have a 2500 sq ft in the hot & humid North Texas area. I have 5 whirlybird vents throughout our roof and only 1 of them is actually spinning the other 4 are held stationary by a metal wire. I’m almost positive that’s not supposed to be the case and have contemplated removing those wires but not sure if this was done purposely. Is there ever an instance where the builder or previous owners would purposely do that? Thanks in advance!
Not sure if your still answering questions but we have a 1960s split level that im starting to dig into with some repairs and noticed that although the previous owner had ridge vent installed when he had the roof done, there is no vented soffit or gable vents present. I don’t think vented soffits are even a possibility because there is no chance of putting in baffles because there’s insulation there and no access due to cathedral ceilings. Would simply adding some gable vents help with getting air moving? Is it even worth it to do anything or just leave things as they are? Thanks to anyone who answers.
Hey brother, I appreciate your council. I appreciate the unbiased, flat-out truth. For instance for the intake vents, ot was said that the best ones, are the ones that go full-length. I hear others saying that thwy should be balanced, and limited to the output of the exhaust vents. I like how you warned, about the elrctric power vents. Those sound logical to be adventageous on the surface. But, hou told us about, how it is possible to puul up mold, from the pipes and not sealed or fully sealed outlets/holes. And, i like how you said, that it is best to have intake ventalation, forgot what they are called, on ALL trusses. And on another one of your articles, you told us how 30 year roofs are not really 30-year roofs (my interpretation). Therefore, i shold go for the 40 year Arhectecture roof, or whatever it specifically is. I like hiw you mentioned the nails! Like 6 nails V less nails or more. Well, I know these concepts, having created anchor points in the mind. I came across this 75-year old guy, who put ridge roofing above his garage. Proof of comcept. If he can do it, than I can probably do it. With God all things are possible, he said. Well, sorry for talking your ear off, lol. I am just happy, that you took your time to make these articles. A lot of what you say, agrees with other professionals. Like for the underlying paper, you suggest 30 Lb, and not Artificial, or the other, that many reccomend. The jury is still out on that for me. I appreciate you raising the issue. It hives me something to think about.
Glad to watch your article. My home is over 20 years old in Raleigh, NC. I have a hip roof with ridge vent and suffix. The attic (the wood) was absolutely “clean”. I added a power fan (with a theromstat) near the top of the ridge vent about 10 years ago. About 2 years ago, I noticed hyphal element started surfacing and some black and white fugus /mold have formed (got it tested and it was iat lowest reportabke level, like 1-10 per squre inches). I had it cleaned by professional anyway. Not sure why but some said the humid winter weather in last few years could be the problem. After watch your article, I have turned off the fan right now. I don’t have water pipe/pumbing up in the attic and I have a dehumdifier in the crawl space. Is it okay to run the fan in the summer or I should just use foam to cover up the fan opening (to avoid short circult the airflow from the suffic to the ridge vent)?
I am in Florida and just got my roof replaced to have the GAF COBRA ridge, I have Soffits along the whole perimeter. Still feels too hot in the attic, looking into ways to manage the heat/ keep the house comfortable in the southern heat Would be interested to know your thoughts on this situation, Would Radiant barriers help? Should I avoid DYI blown insulation ? I notice my air conditioner struggles because the ducts being heated in the attic space
Nice show, so what about the whirlybird put on a 12 or 24 inch extension to add a little chimney affect ever do that? I just had my roof replaced and it’s got that membrane in the ridge vent like you said these and flies you’re gonna find your way in. So I have been thinking about removing the pad, what do you think?
My house was built in 2001, southwest MO. Starting 10 years ago I had to replace about 60ft worth of the rim joist and 80ft of other random floor joists. All damage was due to improper construction, ventilation and insulation which caused moisture damage and attracted termites. It’s BS and although I don’t want to increase the cost of homes, builders and/or inspectors should be held somewhat accountable for things that are blatantly screwed up. My attic has mold in it as well. Tomorrow Ill check to see if the vents on the roof are properly speced for the space. It’s probably mostly due to the moisture issues in the crawl space but you’ve certainly given me plenty of information to be, well, informed. I like your no nonsense approach because this stuff is not funny and can take peoples livelihood by causing repairs beyond expectation/ability/financial means.
Thank you so much, as a homeowner, currently in need of re-shingling my roof, I’ve learned so much from you in this article. I live in Chicago and live in a small Georgian brick home about 1,200 sq feet, post WWll, built around “1945-47” no soffits around the hip roof. I have a power vent, and will be removing it after seeing you reason way, and thanks for that information, but what can I do to achieve positive air flow? add more roof vent lower on the roof closer to the gutters and more near the top of the ridge??? could you please give your advice. Thank you. Louie
Great informative article. I’m not sure if my attic is properly ventilated. My home has 2 ridge vents and 3 or 4 gable vents and soffits around the entire house. I think there’s some insulation in some of my soffits and the areas that used to have a low-pitched roof block those soffits. I like your suggestion of using a power vent for the garage. My garage has a utility room off to the side that doesn’t have an attic space above it. There’s a square cut-out in the ceiling where a light, ceiling fan, or some other electrical device was previously installed. It looks like it could be a good spot to have a power vent installed since the garage and utility room have been hot since I moved into my home.
All the advice I got was to close off the gable vents so the side airflow would not interfere with the airflow up from the soffit vents through the ridge vent. This has helped the upstairs be more comfortable in the summer. Same with turning off our attic fan to not interfere with the airflow up and out the ridge vent.
Good info – Thx. I just added an exterior attic space access @ the ceiling of our 200sf covered back patio area. Although I didn’t expect to find ceiling insulation over the covered patio area, I was surprised to find this new construction home did not have a solid exterior wall framed all the way up to the roof. The rear house wall had approx 4Ft of corrugated sheet (cardboard) forming a short wall to hold the blown insulation in place over the home’s finished ceiling. We do have full length soffit vents and a series of roof box vents. I’m adding a gable end vent above the covered back patio area (East wall) to pull additional hot air out of the attic space. Wish me luck !!
Great article, I came across it as I am considering a whole house fan and needed to understand my attic venting better on my homes pyramid shaped hip roof. The main venting (1967 house in Los Angeles) seems to be the circles near the soffits as scene in the 5:46 picture in this article. Any thoughts on whole house fans or is it not really a Minnesota thing? : )
Triple Vented soffit, or 1-in-3 vented? My roof overhang is only 10″ so I calculated that a single vent soffit did not have enough square inches. I took out my 1-in-3 vented and put in triple vented, because I read the Intake sq inches should match the air outlet (triangle at the roof apex). When the roof was reshingled, ridge vents were installed, and the triangle vents at the roof peaks were left in open. Extra ventilation on the Outlet side is good, IMO. Could you do a article on this important topic?
Quick question! I had an attic with a ridge vent and also soffits on 2 sides of the house, with an attic fan! Rolled insulation on the floor And it’s still hot as hell! I have my air handler, for the central AC up in my attic and gonna change the system and add in a heat pump system. Now can I spray foam the attic rafters to cool it off in the summer time cause I feel like my AC isn’t cooling as good as it should because it’s so damn hot. And of course it’s cold up their in the winter time, and I feel that it’s not gonna let the heat pump work as good as it could. Yay to the spray foaming rafters? What do you recommend I do? Thanks a million buddy!
Good article, So What If You Had A New HVAC Put in The Attic & A Gable Vent at Each End & One About A third Of A single Ridge That Drops at The End Of A 20 ft Addition & All it Open & NO EVE Vents,Were Thinking about About 6 Eve Vents,Per Side & 3 Whirley Birds oh Ya it’s 1500 sq feet & 103 Years Old In Good Shape in SE Texas at 103 & Up Degrees & I Checked The Temp Up There Today & It Was 145 To 155,We Need To Try To Do The Right Thing & On A Budget, I’m Pretty Handy With Fixing & Building Thanks !!!
I have a whole house fan upstairs to pull fresh air into the house through the windows. We use the whole house fan in the spring and fall when AC is not used, or in the summer after returning form a vacation, or weekend away when we turn AC up and returning home we can cool the upstairs and downstairs by turning on the whole house fan more quickly. We had a family of squirrels get into the attic and chewed up the wires on the whole house fan. Do you see an issue with using the whole house fan for cooling, or is it pulling in moisture from the house as you suggested that you should get rid of gable forced ventilation fans. I’d like to replace the whole house fan or get it repaired, but is it Ill-advised to use the whole house fan?
I love-d and enjoy-ed your article. Very well explained by educating us before we get our roofs installed. A concern: when it appears to be that mould has accummulated in the attic one ought to-MUST remove aaall the plywood to make the space issue free? Costly $$$😢$ I am grateful for your wonderful article. Keep up the good work! THAAANK YOU!
I’m dealing with a mess. Hot as hell with no air movement in summer and ice dams in winter. I was going to buy the gable power vents till I tuned in to your presentation. The goal is to keep the attic temps as close to outside as possible? What keeps your living space different and comfortable is the insulation in attic, right? So how does the air flow from these soffit vents into attic if you have the soffit blocked off at the plate by a board going from truss to truss? I thought I heard you say you cut out some of it and install those chutes to allow air from soffit vents up into attic while closing the rest of the area below it with 1″ blown foam insulation, ideally, or standard insulation. Am I getting it? Today I’ll look at little closer at the ridge vent I have and see if there is even a gap up there for air to flow. It’s going to by 90 plus outside today seems like fun! BTW are you out camping?
I went into our attic space recently and noticed that I can see a lot of sunlight through the square vent on the roof – I notice that the square vent you are showing in this article probably doesn’t? There are shoots, but I also notice that the attic is VERY hot – it has insulation up against the room walls next to the attic space, but the heat in the attic is as hot as outside – should this be happening? What should the temperature of the attic be, because I can feel that heat seeping through the walls into the rooms next to it and it gets really hot up there during the summer and really cold during the winter.
I just subscribed, nice informative article! I have a small 2 bedroom 1.5 story house built in 1919 and the upstairs is finished so 2nd floor has a cathedral ceiling. I had Dense-pack cellulose blown in between the 2×4 rafters which helped prevent the bad ice dams i was getting in my gutters in the winter. Insurance company will pay for new roof (hail damage) this coming spring and the roofer wants to eliminate the box vents above the knee wall area then install a ridge vent. In my case I believe with the dense packed cellulose in between the rafters would make the ridge vent useless. eliminating the box vents over the knee walls would mean the only ventilation Id have would be coming from my soffit. In my case would I be correct in thinking I need those box vents above the knee walls for ventilation?
I own a 1430 Sqft home built in 1986 that uses a power vent that is 24″ wide still running since house was built. It’s mounted on the top side wall of the gable roof. The opposite side a wooden leuver vent roughly 24″x20″ is just one of the areas around the house drawing in fresh air. It likely would pass code today with those 16″ x 8″ soffet vents. Thoughts?
Would the power roof vent, solar power roof vent and whirlybirds all work the same? Whirly use air to turn and solar power vents use solar/sun to power it to turn? The power roof vents I guess are wired but don’t they still do the same job as the other two? Don’t they all suck up air? I’m just asking. I was looking into the solar power vents. Thanks.
Hey quick question. I’ve seen insulation/roofing companies to this but I haven’t seen manufacturers say they are intake vents. But would slant back vents work as intake vents if you were to put them just above the eaves, so air flows up through them to the ridge. Assuming they don’t have soffit vents, and for some reason soffit vents weren’t an option. Or if it is a possibility, maybe it’d be cheaper to do that soffits I’m unsure haha.
I have a whole house fan upstairs to pull fresh air into the house through the windows. We use the whole house fan in the spring and fall when AC is not used, or in the summer after returning form a vacation, or weekend away when we turn AC up and returning home we can cool the upstairs and downstairs by turning on the whole house fan more quickly. We had a family of squirrels get into the attic and chewed up the wires on the whole house fan. Do you see an issue with using the whole house fan for cooling, or is it pulling in moisture from the house as you suggested that you should get rid of gable forced ventilation fans. I’d like to replace the whole house fan or get it repaired, but is it Ill-advised to use the whole house fan? 28:20
Thaaank you. This information is Gold. One must learn-understand Ventilation, Insulation of attics…..Bathroom exhaust fans….ahead of just slapping roofinģ shingles without knowing all the systems that results in a functioning ROOF!!! I am so glad i heard yourvideo. I re-listened to it several times so i know it! GRAATEFUL!!! Excellent article! Bless You.
Great article! My home is a modular and every truss ends about 2 feet from the ridge vent by a cross-truss and the then built a “cap” section across the roof top after they lifted the roof sections up with crane to meet the cap section. Do I need to drill holes in that board between each truss to cause the air to find the ridge vent or will it find its way ? Thanks.
Would a gable vent have the same issues as a power vent? I have a cookie cutter house with a 1000sq ft attic and had a new roof put on last year. The roofers put square vents back in to the original spaces venting high and low on the back side (4 pairs). The house does not have any soffits but there is gable vents on either side. I did some reading and it said that the gable vents remove too much pressure in the attic to allow the square vent to work properly so I added a gable fan to the one side so they would at least be pulling air through. It’s not ideal but will I have an issue like you described?
Our house in the desert has little issue with moisture. It’s just heat I need to remove from the attic with active ventilation. Maybe if the monsoon season returns moisture will be more of a concern but the active vents (solar powered fans) would handle that also. The humid regions of the country have much more issues.
Regarding hip roof venting. There are products that sit on the hip that will ventilate that section of roof. They are capped with standard cap shingles. I have seen a couple different products. That being the case, the box or whirlybird solutions are probably not needed or wanted. I would like to see more info on ventilated headwall flashing. I have found a couple of them also. In all cases, I wonder what price would you think reasonable.
I have an older home. Apparently, I had not had any problems with my ventilation in the attic. I have the ridge vents on my roof. I changed my water heater and the company that changed it told me my water heater goes out because I don’t have enough ventilation. However, the new water heater doesn’t have any legs. So, I blame the design. They want me to install their solar powered vents to increase the flow. This is some scam they got going.
Hi. Thank you for the article. We have a brand new home and we were seeking to have our attic insulation topped off to a R38 value since it’s R30 now. It’s white blown in fiberglass insulation. When we had a company come out to our home to give us estimates we were informed of the cost to do that as well as fix the soffit vents since some of them are blocked off or partially blocked since they blew the initial insulation over the openings of the soffit vents in the attic. Then the company started telling us we can also place a solar attic fan to help cool the attic down for the summer months. In addition to this they informed us of another option of spray foaming the entire attic and seal everything in and then remove the current blown in insulation. We have since learned that attic fans have been known to cause more issues in more than one potential way. Also we have learned that the spray foaming option can cause lenders to avoid giving loans to people that may be interested in buying your home if you sell the home. There are also several other negative things that are being said about the choice to do spray foam. The idea is so appealing to have the attic look very clean as well as not be so darn hot or cold and become a sorta conditioned space. But we have also asked the same company how we keep moisture from becoming a problem when you seal the entire attic air tight. Anyone with common sense would know that humidity will be in any space and if you do not have any AC or Heating air flow being circulated into air returns and then back out vents will become a problem.
I would be curious about my attic, I sometimes feel it has too much ventilation. I have a gable roof home (simple rectangle) with gable vents (about 12×24″) on each end, soffit vents, and a ridge vent. While working in the attic I noticed that the airflow seemed less than stellar. I am used to soffit + ridge vented attics that have a noticeable up-draft to them and wonder if the placement of all my ventilation is not allowing for proper flow throughout the attic.
Thank you for your article. I live in Hawaii on the leeward side, which gets more sun than rain. I’ve not a handyman type but I do try to educate myself about homeownership. This article covers a lot of information which makes me think about the roof, venting, moisture and concerns. This has been really educational and I subscribed because now it makes rethink about an earlier decision when I had my home reroofed about 11 years ago. I think I did one of those things you talked about. I had the roofers install a solar fan to vent out the roof crawl space. It worked then, but doesn’t now, as mentioned about the spinning stopping. I was debating about replacing but after seeing that section about the power unit and it sucking up moisture for mold, now I have to have it inspected and consider what other options on venting as well as replacing/repairing the solar fan. I’ll have to research your articles for that information. Mahalo (thanks) from Hawaii. I hope you continue doing more. Take care.
I have a 1958 ranch house in NJ with 1500 sq feet. All it had was 2 gable vents and a little box vent, about 100 sq inches total ventilation. The roof was 25 years old and there was no problem, no mold but I wanted to get a new roof so contractor said we will replace and keep everything the same. I said look at the other houses some of them have ridge vents. The contractor said it doesn’t do anything since there are no soffits, the new siding just covers up the solid woof soffit. Your house was designed with just 2 gables vents and since there was never a problem we just replace the roof because plastic ridge vent mice can just squeeze or chew through and attic fan is no good.
Question on the power vent statement. I am researching adding ventilation to one room of the house. It is a cigar smoking room. I’ve taken steps already to prevent the smoke from entering the rest of the house and that works very well. Also air cleaners in the room. I’d like to add a vent to specifically draw the smoke air out of the room and vent that outside. Would a power vent be an appropriate solution? This would be connected to a single room via a duct and not exposed to the entire attic space.