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Whole House Fans Vs Attic Fans
As summer quickly approaches I wanted to share an archived post about whole house fans and gable attic fans. This post was written to help a reader decide which type of attic fan was best for her home.
Marrisa wrote to me and wants to know about whole house fans vs attic fans.
I’ve been considering installing an attic fan in my house, and wondered what your thoughts were. First, is an attic fan the same thing as a “whole house fan?” I’ve seen sites apparently use the phrases interchangeably, though I don’t know if that’s correct. Second, do these fans save a significant amount of energy versus central air?
There is a huge difference between Gable Attic Fan
Gable Attic Fan
Gable Attic Fans – are mounted to the gable wall inside the attic behind a decorative louver. The gable attic fan is connected to a proper power supply and a timer. The timer allows the fan to run during the hottest portion of the day. The gable attic fan helps reduce the attic temperature to help prevent heat transfer down through the insulation and into the living space. Gable attic fans are typically much cheaper than whole house fans and also easier to install.
Whole House Fan
Whole House Fans – are mounted in the ceiling between the living space and attic. They are typically located in a central hallway to help evenly remove warm air from the living space. When a whole house fan is turned on it helps draw warm air out of the living space while drawing in cooler outside air from open windows.
This system is most effective when the temperature outside drops below the temperature inside the house. Whole house fans can be very effective in cooling down a house in the morning and evening hours. In some parts of the country they can be a very inexpensive alternative to central air.
Whole house fans typically have some type of louver and/or insulated door that closes when the fan is shut off. This helps keep warm and cold air out of the living space when the unit is not being used.
Attic Fan Installation
The other part of Marissa’s question was about installing these units herself. I’d rate the installation of a whole house fan as a difficult / advance home improvement project. I’m not sure I would recommend this project to most DIY folks. Having said that, if you’re really comfortable with electrical work, framing and cutting drywall then you can probably tackle the job. You can probably cut in the unit and get it ready then hire an electrician to wire it up.
Do any of you have a whole house fan? Would you recommend one for others as an alternative to central air?
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Thank you for the response, Todd! I appreciate it. I’d love to get a whole house fan put in, since the outside air temperature is often cool enough to be comfortable, if I could just get it *moving* through the house. Sounds like a whole house fan would fit the bill nicely. (FAST response, too!) Thanks again!
We have a non-working attic fan.. I would say gable, but we have no gables. I’ve been wondering what might be required to get it working again… it sure would be nice to have in the summer!
Timely post! Here I am making up a budget for home improvements, with an attic fan at the top of the list! The thing that had me worried, is our one estimate told me they’d have to cut a hole in the roof (this was over the phone) and then my dad got me all worried about them doing it wrong and our roof leaking. However, we do have a little gable vent just like that in our attic, so maybe it just needs a fan installed…or maybe there is a broken one already up there!
I have one more question…what about solar attic fans? I was talking to a green building guy earlier this summer who recommended one, but again my dad said that regular attic fans probably save more money in AC costs than the use in electricity any way. And the solar fan costs several hundred dollars more upfront. What do you think?
@ Green Me – It is possible that more ventilation is needed in the roof, eaves, gable or soffit to allow for the volume of air being moved by the whole house fan. If you already have gable vents they might just need to be resized. I would get multiple quotes from reputable companies and ask lots of questions.
Solar attic fans are a great idea, however, they are not the same as a whole house fan.
We have a whole house fan currently in our home, as well as put them into all the homes we build. I strongly recommend & believe it to be highly effective for a quick-response cooling of the entire house!! I grew up in NJ, in a home w/ both central air as well as a whole house fan- we all enjoyed the natural air far more than the produced chilled air of the AC!
Easy to install to boot!!
) It is placed between the floor joists- and can be positioned nearly anywhere w/in the parameters of the central hall (we aim to not have it w/in direct sight when you come up the stairs for better esthetics). Genius!
I grew up with a whole house fan, if not to hot outside it was great. And when the AC went out once it was a life saver. we would open only the windows in the rooms we were in to get max airflow from those windows. it creates an artificial breeze coming in from the outside. I would install both. the gable fan ( I would presume it is on a temperature controlled switch) can cool the attic when your not using the whole house fan to help keep your bills down even more.
When I checked out solar fans, they were only 500 CFM. (They move 500 cubic feet of air per minute). Electric ones are usually 1200 to 1600 CFM, and they run at night. (Mine shuts off at around 10:00 usually) If you are considering a solar fan, remeber, your AC may run more than if you got a powered attic fan.
I have an attic fan which is not working. It’s approx. over 21 ys. old and was in the house when I bought it.. The fan is installed in the roof. I’ve been quoted a price of $500.00 to replace (prob. doesn’t include labor, the quote was left on my phone message ). Since, what I have is so old, will it be hard to replace and not leave a leaky roof? Also, is this how it’s done currently? Good price? It’s already getting very warm in the crawl space attic. Thanks
@ C Muschlitz – Really hard to say without seeing how the fan is installed. Some fans are indeed installed through the roof. $500 seems to be a fair price. Be sure there is adequate power and fan volume.
This is great info. We bought an older home and are planning to get a new roof installed this summer. The attic has floor boards for storage and a pull down ladder. Since we plan to store stuff in the attic, will we still be able to install a house fan or will we only be able to have an attic fan installed. I’d like to have this figured out before the new roof goes in so any holes in the roof can be taken care of with the roofers. Based on the location of the pull-down steps, it looks like the house fan will have to be installed close or if not next to the pull-down steps…any issues with this?
@ Brian – Many people have attic storage and whole house fans. The only issue in my mind is dust/wind near stored materials. You just need to keep sufficient distance from the fan to stored materials. Whole house fans are a very effective way to cool your home. Best of luck!
Bought a home w/whole house fan installed in hallway. It does suck in the outside air and pollen and dust. We recently removed it and will be installing gable fans to remove hot attic air only, without the problem of dust and pollen being drawn in. There is something to be said about clean AC air.
[...] Difference Between Whole House Fans and Attic Fans Home Posted by root 3 hours ago (http://www.homeconstructionimprovement.com) Choosing between an attic gable fan and a whole house fan can be quite confusing considering a solar fan remeber your ac may run more than if you got a powered attic fan add your comment below or trackback from your own site powered by wordpress log in en Discuss | Bury | News | Difference Between Whole House Fans and Attic Fans Home [...]
[...] Difference Between Whole House Fans and Attic Fans Home Posted by root 6 hours ago (http://www.homeconstructionimprovement.com) Choosing between an attic gable fan and a whole house fan can be quite confusing considering a solar fan remeber your ac may run more than if you got a powered attic fan add your comment below or trackback from your own site powered by wordpress log in en Discuss | Bury | News | Difference Between Whole House Fans and Attic Fans Home [...]
I had a very powerful and noisy attic fan that really pulled the air up on out, but I would like one of the new quiet whole house fans instead. Does anyone know if you can get them to run on a timer? Or does anyone know about an adequate solar power whole house fan?
Hi. Some general comments on fans. The full house fan will tend to pressurize the attic space and if the attic is close to being “air tight” a higher pressure will be created on the discharge of the fan and it won’t be able to move the designed air volume, so the attic needs to be able to breathe feely. The attic gable fan also needs a sufficent inlet area for the outside air at the opposite end of the attic to allow an air flow path through the attic for it to be most effective. It seems to me that the two would completement each other. The gable fan could be switched on and off using a thermostat mounted in the attic space to help save energy. With both fans, the volume of air required for effective cooling should be professionally determined; and when comparing quotes make sure that they are the same CFM fans since smaller fans = smaller price = smaller cooling and vise versa.
NOTE from Todd: I’m not going to delete this comment, however, I do believe the commenter didn’t really read this article. I NEVER suggested running an attic fan while running A/C. Read this comment with a grain of salt.
DO NOT USE POWER VENTILATION IN ATTICS> PERIOD!!!!!
Whole house fans are helpful in cool climates. DO NOT RUN WHOLE HOUSE FANS WITH THE AC ON!!
OMG!!! This is just the sort of (well meaning but) misinformation that is rampant. I know this is going to sound completely insane to most people. I will be happy to go on and on about my qualifications to make this claim if you like.
Why?? You can not create positive pressures without creating negative pressures. When you are mechanically pulling air through your attic, you are creating a situation where the pressure inside your attic is lower than the inside of your home. Conditioned air will be drawn out of your home into the attic through cracks, exhaust fans, attic access doors and stairs, around the edges of your cieling, and wall opening where light switches and electrical outlets are located. Now, you have a lower presure inside your home than outdoors. The cool air that left your home for the attic will now be replaced by unconditioned air from outside. Thia air will be drawn in around the cracks in windows and door, ect.
Bottom line. If you want to cook your atic with your AC system and then add the additional load fromoutside infiltration, go ahead. And to add insult to injury, you are using (waisting) additional energy to operate the attic fan that is causing this mess!
So, what is the answer?? Natural ventilation. Vents in your boxing coupled with ridge vents. Oh, and one more thimg. I read that ridge vents do not work because hot air rises and when the air hits the vent, it will not move sideways and slightly downward. That is not true either. Air that is heated expands. When air expands in an enclosed space, pressure will ride. The rise in pressure will force the air out of the ridge vent with no problem.
You may wan to check this website and others to verify my claim.
http://www.energystar.gov/index.cfm?c=diy.diy_attic_ventilation
@ Bill – I think you completely mis-understood this article. I NEVER suggested running AC and any type of attic fans. What I suggested was using a whole house fan when you’re NOT using A/C. These fans are used here in New England with very good results as a way to pull cool outside air into the home. Proper ridge vents and soffit vents are absolutely necessary and I completely recommend them. I hope you’ll go back and re-read my information and correct your statements.
Hi Todd,
My intent was NOT to disagree with you on whole house fans. In cooler climates, they make Perfect Sense. Here in the South, we usually use economizers to pull fresh cooler outdoor air in and distribute it during cool weather. This is especially beneficial in places like restraunts that have a lot of internal heat loads in cool weather. In effect, what you arte talking about is free cooling. That is great!!
The main point of my comments was to stimulate conversations on mechanical attic ventilation pros and cons. Sorry for the confusion!
[...] Todd notes in his article, an attic fan is different from a whole house fan. A whole house fan is normally installed in the ceiling of the topmost floor of the house, [...]
We live in Riverside, California and it gets pretty hot here. Would attic gable fans be better for removing the hot air from the attic? Or, would using a whole house fan be a better solution? Does the whole house fan work well when the temperature is hotter outside than in? Thanks.
@ Jordan – Whole house fans won’t really work well when it’s really hot outside. They are intended to draw in cooler outside air. A gable attic fan can help keep temperatures down in your attic
thanks for your help
Todd, thanks for the help.
Could you tell me how many gable attic fans should be used per how many sq ft of attic space we have?
How many gable attic fans should be used per how many sq ft of attic space we have?