Attic Fans - Do They Really Help Keep Upstairs Cool?

My experience is with the attic fan in my grandmother's house. The house is about 150 years old and has no AC at all, just a giant fan in the attic (maybe 8-10 feet across). If it is cooler outdoors at night it really helps. If it is so hot there is no cooler air to draw in then it is still uncomfortable.

I've had an attic fan, sometimes called a whole house fan in all my houses since 1980. When I built and designed my "dream home", It had an attic fan in it.

They reduce the heat tremendously. I turn mine on when the outside air is 10 degrees cooler than the inside air. They also reduce the amount of electricity you use. You should look upstairs and see how much insulation is on your ducts. The thicker the insulation the more efficient your cooling system will be.

Home Depot sells attic fans and they will also install them. I think Lowes will do the same. Almost all home improvement stores sell and install them.

Good luck to you and yours.

Yes, they really do work. Let me tell you, ours broke about two years ago and we haven't fixed it yet, but are about to. I've noticed the difference in the summer temps in the house; they go up higher faster now that ours is broken.

I had one in a very humid climate where eveporative coolers were not feasible. It cooled our whole house at night because it pulled all the hot muggy air out and kept a breeze circulating. Your already sweating in a humid climate, so the breeze going over you is really cooling. It cut way down on my energy bill because I didnt have to run the a/c as much at night. Still needed it in the daytime.

YES YES YES!!

Our house does not have a lot of overhang to properly ventilate the attic. The heat would collect in the attic all day and then blanket the house with the heat and humidity in the evening. We had just a regular contractor install ours and what a difference!! The attic fan will run all day but it is sooo comfortable upstairs.

ETA: BrownEyedGirls is referring to a whole house fan. That one you do need to have your windows open because it pulls all of the air out of your home and fresh air from outside. The attic fan simply has a thermostat and draws the air out of the attic once that temperature is reached.

PS We also have ceiling fans in our bedrooms.

My concern is that whomever installed your ac either did it wrong or gave you too small a unit or didn't duct it correctly. I do feel attic fans cut costs and can have many days of no ac running. Check with the installer of the unit and see if they can assess the problem as it should be a courtesy or word of mouth will damage his business.

Attic fans only work when the night air is cold. And you must have your windows open to run it. We had one in my childhood home, it did do its job on cool summer nights. But nothing for those hot summer nights.

Is the ac unit still under warranty? Either it isn't big enough for your house, it wasn't installed correctly or it isn't working right. I would have a professional come out and take a look.

We had a whole house fan in the hallway ceiling upstairs when I was a kid. It worked. We had to have all the windows open and turned the ac off. It helped if the outside air was cool. Not so much when it was in the 90s at night. It was really loud so if you get one, be sure to inquire about how noisy the unit is.

Attic fan? Yes it would help get the heat out of the attic. Not sure about making the upstairs much cooler.

An attic fan can do wonders to cool your house in the summer, all the hot air stored up there just raises the temp of your house. It is also a very good idea just for safety, an attic fire would destroy your house.

I LOVE my attic fan. It cools the entire house (ranch, so one floor). Just make sure you get one that is big enough.

An attic "exhaust" type fan blows the hot air out of your attic. It does help keep your house a bit cooler, and it also prolongs the life of your roof. This is something you set and forget -- literally, its up there and you dont do anything to it. I'm surprised you don't already have one, they are typically part of a roof installation. If you dont' already have one, I'm not sure I'd put one in now if you are anywhere close to getting a new roof. If you are a couple of years away from a new roof then I'd wait, do some research, and pick a lighter colored shingle too. They are generally installed by roofers, as they involve cutting a hole in the outside of your roof and flashing around the fan. If you do this, we had some roof work done by Showalter roofing once and would recommend them. We have a home that was built in 1975 that we have lived in for 8 years. The upstairs was always much hotter than the downstairs, sometimes unbearably so. We had a lot of new insulation blown into the attic and it no longer feels like the ceiling of the 2nd floor is part of an oven, and insulation isnt' that expensive compared to other things you can do. We have something called "trol a temp" -- it is a damper system, which is so-so. In theory, the two termostats, one for upstairs, one for downstairs, work together, to direct the cold air upstairs. The trick is to set the upstairs to a colder temp and the downstairs to a warmer temp which is also warmer than the temp the downstairs currently is. If the downstairs heats up enough to trigger the A/C for the downstairs, the dampers switch back to directing the air to the downstairs. For some reason, my husband doesn't understand this, (even after 8 years) and I can wake up sweating to walk downstairs to a freezing kitchen. He will then tell me that he was hot, so he lowered the temp on the thermostat DOWNSTAIRS which was completely the wrong thing to do. It gets annoying to keep going upstairs to fiddle w/ the thermostat. A true 2 zone system means a seperate A/C unit that serves only the 2nd story of your home. This of course will work the best and also cost the most.

As a kid, we had a "whole house fan" which is sometimes also called an "attic fan." This is basically an alternative to A/C. If you are running a whole house fan you don't air conditioning on too. For the whole house fan, you have a big fan mounted into the side of your house up high (inside is probably in your attic.) Then on the second floor, maybe in the upstairs hallway, there will be a second door or hatch to open when you have the fan on. You open all the windows, turn on the fan, and the fan is very powerful and pulls air in through the open windows. It creates a nice breeze and does cool things off, especially at night. One thought I have though is I grew up on the East Coast, and even though we had plenty of hot days, the nights were always cooler than they are here. In the midwest, it seems like once it gets hot, it stays hot. This will never be better than air conditioning though, so I'd look at some of the other choices.

Good luck!

We live in a 2 story and have the same problem. I just have to turn the air down 2 degrees at night when it is really hot to sleep good. Now when it is spring or fall, yes the attic fan works wonders, as do running the fans. We just got a new skylight upstairs, and it is made with "low e" (hope i got that right) glass so the heat does not come through. It has made a significant difference in the heat up there.

I'm curious to find out what people say... We have a two story house in Texas and it's been a very HOT summer already... One thing we have done so that our upstairs isn't as HOT as it could be, is closed some of the vents on the first floor, in the rooms we aren't in too much. That makes a huge difference, also, at night, we move our temperature down 4 degrees so we can sleep better, it's on a timer so around 6 AM or so it starts to go back up...

One thing to think about is allergies. My daughter's allergist said no attic fans due to daughters high pollen allergy. Attic fans suck in a lot of pollen and dust. FYI

Also, have you tried adjusting your dampers coming off the ducts? You can force more air upstairs and.less on main floor and then reverse in the winter. I'm also wondering if you got a.big enuf unit for your house. Our house has a builder grade size and we and neighbors have been told by various companies that the units are not big enough for house size. So frustrating.

IMO attic fans are great b/c without them, the hot air that rises and accumulates in your attic....stays in your attic and the rest of the house takes longer to cool down. We have a single-story ranch house with no air conditioner and temps get into the 90s during the day, sometimes the 100's, but it cools off enough in the evening that a combination of the attic fan and opening the windows and using a standard fan to pull the warm air out of the house works 99% of the time to keep things comfy enough for us (if we've had several consecutive days of 100 degree weather it's a bit harder to cool down).

Other things that help a lot are - good attic insulation (we felt the difference between our first summer here and the second one, after DH added insulation to the attic) and, when it's time to re-roof, use as *light* a color of roofing material as you can stand, because the lighter colors reflect more UVs so more reflected light/heat = less heat absorbed into your house :-).

Interesting question...I learned a lot and think I'm going to look into an attic fan for our house. It gets so HOT in here. We have no AC so this summer has been all about trying to keep the house cool during the day. By evening its so much warmer inside than outside so this is good to know!!

thanks for posting this question!

We designed and build our little house years ago to include what's called the "stack effect." Since warm air rises, we have a couple of clerestory windows on our loft that we open at night, when we open downstairs windows. The hot air in the house leaves as cool air is drawn in downstairs, and by midnight, most nights, the house is nice and cool. We shut out the heat early in the day, and don't have to use our heat pump often to cool off.

If you already have ductwork in your house, you might want to consider a heat pump. They are very efficient, and can both cool in the summertime and heat in the winter. My only complaint is that the motor is a bit noisy, but so worth it to know we're getting an economical blast of warm or cool when needed.

An attic fan sits in the attic and draws cooler air through the windows and out the vents in the roof. The windows have to be open for it to suck anything out.

We had an attic fan back in the 70's or 80's and I could not feel any difference when it was first turned on. My BIL pointed out the at the curtains were moving and starting to stand out a bit. By the next morning I was wrapped up in 2 blankets and cold. It sucked in all the night air and really cooled off the house during the night.

Part of the issue with sleeping in the hot rooms is that the furniture is hot, the floors are hot, the walls are hot, etc...the air conditioner can't keep it cool if the home it's self is the issue. It sounds like you need to add some window units in the hottest rooms upstairs. The attic fan will help at night but for general cooling the window units will do a better job.

We have a ranch and our attic fan does a pretty good job of cooling the whole house. We have window a/c units in the bedrooms but none in the main living areas of the house so it makes a big difference for the main parts of the house during the day.

Your story sounds very much like our experience with our second floor. And I'm pretty sure you are talking about an attic (exhaust) fan that is installed through the roof ...NOT a whole-house fan that is massive, loud and draws air from the other open windows in the house.

Yes, the attic fan is definitely the first step to helping keep the second story cooler. We had one installed a couple months ago and are definitely noticing a difference -- mostly at night when the sun goes down. Prior to the fan, the upstairs continued to heat up more and more, even after the sun went down. Now that the attic fan is blowing out the hot air from the attic, we are noticing a considerable difference.in the temperature of the bedrooms.

Our next step is to add more insulation to the attic. We got a quote from the same company that installed the attic fan. They were able to estimate how much more would need to be added to make a significant and noticable difference during both the summer and winter. We were very impressed with the company and will follow through on this when the time is right for us.

We used Superior Attic Fans. http://www.superioratticfans.com/ The fans they install are rated the quietest on the market. (We can't hear it at all.) Believe it or not, we found them via Groupon -- and they had an excellent deal ($289 for fan and installation.) If you call, ask them if they would still honor their Groupon pricing. Who knows -- maybe they'll give you the deal!

If you have any other questions, send me a note.
Hope this helps!

We have a solar attic fan and it makes going in the attic bearable. I think it also helps in general keep the house more even. Our downstairs is partially underground so it's always cooler there.

Jo W. mentioned "zoned heating and cooling." We have a 2-story home with a full finished basement that has the same problem you mentioned. The air conditioning keeps the first floor comfortable, while the basement is freezing and the upstairs is hot, so we recently got an estimate from an HVAC contractor to "zone" the house. The estimate was $5,079. Ouch. I'm planning to go on ServiceMagic.com to seek bids from other HVAC contractors to see if any is less. If we do go forward with zoning the house, it will be because, in the long run, the cost of doing will be offset by the savings in decreased air conditioning costs.

BTW, we have a whole house fan, which helps, but it doesn't totally solve the problem, and, as other responders have mentioned, it requires that the outside temperature be quite a bit cooler than inside the house in order to be effective. We also recently had R-30 insulation blown into the attic (it still had the original rolls of much lower "R- value" insulation from when the house was built in 1978), which seems to be keeping the house cooler overall.

We had this issue as well, we even we going to put in another unit just for the upstairs but was told the house was not big enough to do this, but was told to do a zone system. We love it and have had it for three years now, we were told the attic fan would not make a big change. Also our zone system is you have a thermostat on each floor 1 st and 2 nd and they put in new ducts that have dampers inside them that open and close if I want my 1 st floor to be 74 and the 2 nd to be 72 then when the first floor gets to 74 the dampers will close off the first floor and stay on to cool the 2 nd floor to 72 you can also have them the same temp and the dampers will just open and close as needed to keep each floor at the temp you put on that thermostat, so we still only have one main unit just two thermostats and ducts with dampers in them

If we had a two story we would have zoned heating and cooling. In other words there is an AC unit dedicated to just the upstairs. Still even with that sometimes the upstairs unit runs all the time but at least it is cool.

I don't know what effect attic fans would have. Your attic temps are off the charts, well above the outside temperature so an attic fan will cool the attic. Not sure what that equals in temperature inside the house since you have insulation and all.

We have a whole house fan, which is not an attic fan by the way, which is amazing but can only be run at times when the outside temps are at least 5 degrees cooler than in the house or at your target temp for the inside.