attic fans

[sesack1]

I am trying to decide if an attic fan is worth the $$$ and effort to have installed. It seems like it would be a help but practically would it help anything. Any good info is needed.

[tuccillo]

If you are referring to a powered attic ventilator (fan in the roof of your house), probably not. This has been researched and is generally shown to either do no harm or result in an increase in energy use. If you google it you should find many objective references.

I am trying to decide if an attic fan is worth the $$$ and effort to have installed. It seems like it would be a help but practically would it help anything. Any good info is needed.

[graciegirl]

If you are referring to a powered attic ventilator (fan in the roof of your house), probably not. This has been researched and is generally shown to either do no harm or result in an increase in energy use. If you google it you should find many objective references.

You beat me to it.

Click on search above, sesack, and type in attic fans. The summary of information seems to indicate them to be close to useless. The folks who disagree are the ones installing them.

[villagetinker]

I have a garage exhaust fan that cools the garage, and sends the air into the attic, which forces the hot air out. DISCLAIMER: I do not have specific measurements to show and changes in power usage as we installed the fan the first summer we were here. The attic thermometer drops by 20 degrees or more when the fan turns on.

This is a 120 vac powered fan, 1100 cfm and is controlled by a thermostat, so it will turn on late morning, and run until after sunset. NOTE: I have lots of ventilation openings in the garage doors to allow for this amount of air flow.

I agree with doing some research, as many of the points are valid.

Hope this helps.

[Sandtrap328]

I have an attic fan that is solar powered and therefore has no energy cost. It was installed by Solar Guys. The attic fan is a good investment and I would recommend a solar fan.

[tuccillo]

The issue with fans through the roof of your house is they create a slight vacuum in the attic and replacement air can come through the soffits as well as from the air conditioned space in your house through recessed lighting and other imperfect seals. In addition, the primary mechanism of heat transfer in the attic is by radiative transfer from the underside of the roof sheathing. Attic ventilators won't address this primary method of heat transfer. This has been objectively researched. Spray foam insulation on the underside of the roof sheathing will result in a cool attic because if dramatically reduces radiative transfer to the rest of the attic. I had this in a previous home.

I have an attic fan that is solar powered and therefore has no energy cost. It was installed by Solar Guys. The attic fan is a good investment and I would recommend a solar fan.

[DangeloInspections]

I hesitate to post on this subject, because it is indeed contentious. I am in attics everyday. I walk all over them during a typical home inspection. Here is a good objective article on the subject;

Don't Let Your Attic Suck | The ASHI Reporter | Inspection News & Views from the American Society of Home Inspectors (http://www.ashireporter.org/HomeInspection/Articles/Don-t-Let-Your-Attic-Suck/2177)

Make sure you also click on the attached articles within this article above.

Part of the problem here is that I think there is a bit of the "Placebo Effect". Once a person spends hundreds of hard earned dollars on something they will lean towards feeling that it was a good expense. Added to this is the fact that in some cases, the attics ARE a bit cooler. SO....the question is, what are you trying to do here?

Usually the answer is, "Trying to cool the attic so my A/C will run less". The problem here is that air is going to be drawn from it's least restrictive space, which appears to me to be the saucer and ridge vents. This can cause "short cycling" and then stratification of the air below. The air then just above the insulation will not be that much cooler. In short, ACTIVE attic ventilation can disturb the natural passive ventilation the attic is designed for.

Personally, if I were to spend my money I would first consider adding a bit more insulation first, as even the newer homes are currently an R-30. This meets code of course, but insulation is so inexpensive that going to an R-40 or more would have a payback, even with the law of diminishing return.

Many people get confused between having a fan on the roof or gable to exhaust the attic, and having a fan to exhaust the air out of your garage INTO the attic. They are completely different systems. If your goal is to cool down the garage by pushing air into the attic and out the ridge vents...this is different, and could work well as long as you have sufficient air INTAKE to make this work. Understand that I am not addressing any fire or wind mitigation concerns that this may impact. I am also not addressing how this affects the normal attic air flow from your soffit intakes to your ridge vent exhaust.

Lastly, please know that I have no "horse in this race" and do not care if you agree with this or not, or if you buy one or not. I do not sell these or benefit if you have one or not. I do NOT want to step on the toes of those who feel different than I do on this subject, or make a living selling these. Folks seem to have strong feelings about this, and I do NOT want to make enemies here....I only want to help by offering some articles written by experts smarter than I am.

Folks ask me questions everyday, like what is my opinion on Gutters, Water systems, Roof vents, Solar tubes, painted driveways, Lanai drainage, etc....My opinion is just that. I try to be knowledgeable and unbiased and try to do good research. Your opinion may be different, and I am not always right...(ask my wife)....my only goal is to help.

Respectfully, Frank

[mixsonci]

Is there a problem if I don't do anything? I had the garage doors insulated and some vents cut into the door, but nothing else. Is that a problem, do I need to do more? What happens if I don't?

[champion6]

Is there a problem if I don't do anything? I had the garage doors insulated and some vents cut into the door, but nothing else. Is that a problem, do I need to do more? What happens if I don't?There is no problem if you don't do anything.
You already did something.
You don't need to do more.
If you don't do more, you will have more to spend on enjoyable things :MOJE_whot:

[RickeyD]

Is there a problem if I don't do anything? I had the garage doors insulated and some vents cut into the door, but nothing else. Is that a problem, do I need to do more? What happens if I don't?


Can't hoit !

[twoplanekid]

I had my garage door insulated by the same company that did my brothers garage door and ceiling. His house is seven houses down the street with the garage facing east like mine. As his garage is so much cooler than mine, I may insulate my garage ceiling this Fall when I return to TV.

[kcrazorbackfan]

Okay to believe what you want, everyone has opinions; one thing I don't and won't do is blow smoke up anyone's a** and tell them to do something that doesn't work. Here's what I did and it's cooled my garage and attic roughly 20 degrees - I put a radiant barrier on my garage door that faces west (bought the material at Lowes to do it). I then put 2 vents in the bottom corners of the large garage door, 1 vent in the center of the golf cart door and a large vent in my pull down staircase. I then installed a thermostatically controlled 1,600 cfm attic fan in the roof to pull the hot air out of the garage and the attic. It has made a big difference in the temp of the garage and attic. Will it help cut down on my cooling bills? I don't freaking care if it doesn't, but it's sure made work time in the garage more enjoyable and storage area in the attic more bearable.

[DangeloInspections]

Well, this thread has kind of morphed to cooling the Garage.....dependant on how much time one spends in the garage, and what direction your garage door faces, I think it is an excellent idea to insulate the garage door. Also, any time you have cooler air constantly flowing into your garage it will keep your garage cooler.

Insulating the garage door cuts down the RADIANT heat build up in your garage. Generally one does not insulate unconditioned spaces, like the garage and the Lanai....but some folks who HAVE insulated their garage ceiling and have even installed radiant heat barriers above the garage have stated they have found their garage much cooler.

It is unfortunate that the builders do not give insulated garage doors as an option, as they do not cost much more than the entry grade Clopay garage doors currently installed. I recently replaced my two garage doors with the top of the line Clopay "sandwich type" door that has steel on both sides with 2" of polyurethane in between, giving me almost a R-20 garage door. This has made my garage much cooler. My home faces southeast.

Frank

[DeanFL]

Frank D is a great source of home info - he did our warranty home inspection...

Our house faces east and the garage door radiates a lot of heat in mid-morning. Plan to insulate the door - and Frank is SO right - why the developer didn't offer that as an option...

I had a solar attic fan in my previous house. I consider it a waste of $$, was about $800, when they installed 2 solar tubes. Don't feel the solar fans pull much at all to warrant the $.

I read many sources re attic fans, and that new homes are quite tight now, the fans may create a negative pressure in the attic and actually pull conditioned air from the house thru ceiling elec boxes, recessed lights etc. I recall a few times when I had the garage access door open a crack and felt the cool house air rushing out to the garage when I reentered. It's one thing to cool the attic, but at what potential cost if it pulls some conditioned air from the house?

I did install a 3 speed fan in the garage ceiling, into the attic. The garage is a bit cooler and so is the attic - I'd guess pushing more air there and out the soffit and roof vents.

My 2 cents.

[RickeyD]

Okay to believe what you want, everyone has opinions; one thing I don't and won't do is blow smoke up anyone's a** and tell them to do something that doesn't work. Here's what I did and it's cooled my garage and attic roughly 20 degrees - I put a radiant barrier on my garage door that faces west (bought the material at Lowes to do it). I then put 2 vents in the bottom corners of the large garage door, 1 vent in the center of the golf cart door and a large vent in my pull down staircase. I then installed a thermostatically controlled 1,600 cfm attic fan in the roof to pull the hot air out of the garage and the attic. It has made a big difference in the temp of the garage and attic. Will it help cut down on my cooling bills? I don't freaking care if it doesn't, but it's sure made work time in the garage more enjoyable and storage area in the attic more bearable.


I plan on putting the exhaust fan in the ceiling of the garage so as to create a negative in the garage and a slight positive in the attic. This will provide ample air exchanges through the garage but not pull but push the exhausted air through the ridge and soffit vents.

[tuccillo]

My garage doors face west/south west. I insulated them and this cut down on the radiant heat quite a bit. My garage is now within a few degrees of the outside temperature in the afternoon.

Okay to believe what you want, everyone has opinions; one thing I don't and won't do is blow smoke up anyone's a** and tell them to do something that doesn't work. Here's what I did and it's cooled my garage and attic roughly 20 degrees - I put a radiant barrier on my garage door that faces west (bought the material at Lowes to do it). I then put 2 vents in the bottom corners of the large garage door, 1 vent in the center of the golf cart door and a large vent in my pull down staircase. I then installed a thermostatically controlled 1,600 cfm attic fan in the roof to pull the hot air out of the garage and the attic. It has made a big difference in the temp of the garage and attic. Will it help cut down on my cooling bills? I don't freaking care if it doesn't, but it's sure made work time in the garage more enjoyable and storage area in the attic more bearable.

[WhoDat]

Well, this thread has kind of morphed to cooling the Garage.....dependant on how much time one spends in the garage, and what direction your garage door faces, I think it is an excellent idea to insulate the garage door. Also, any time you have cooler air constantly flowing into your garage it will keep your garage cooler.

Insulating the garage door cuts down the RADIANT heat build up in your garage. Generally one does not insulate unconditioned spaces, like the garage and the Lanai....but some folks who HAVE insulated their garage ceiling and have even installed radiant heat barriers above the garage have stated they have found their garage much cooler.

It is unfortunate that the builders do not give insulated garage doors as an option, as they do not cost much more than the entry grade Clopay garage doors currently installed. I recently replaced my two garage doors with the top of the line Clopay "sandwich type" door that has steel on both sides with 2" of polyurethane in between, giving me almost a R-20 garage door. This has made my garage much cooler. My home faces southeast.

Frank

I think insulating the garage door is a good idea. My garage (when the house is finished) will face West and get the full afternoon sun. What is the best way to insulate the door? Also, how do you install vents in the garage door? Can the material be purchased at Home Depot? I would love to cool the garage down since I expect to spend a lot of time there.

[DangeloInspections]

There are a few ways to insulate the garage door. Some places install a "foil bubble wrap" type. I do not really recommend this type.

You can get 4x8 sheets of thermax type insulation and cut them and friction fit or liquid nail them in place. An inexpensive project.

A better looking option, but more costly is buying the insulation kit made by Clopay, the same maker as your door. You can buy these kits at Ro-Mac on Rolling Acres Rd. You can install it yourself or they will come out and install it. The side you see is a heavier white plastic that looks nice.

Vents are a more controversial issue. Some folks just by soffit vents and screw them on. Some feel this is unsightly, and would compromise the wind rating, etc of the door. I would feel better about opening the window a bit and securing it, or in windowless garages one could install a intake vent in the wall.

I have actually seen a few folks have small fins cut into the bottom section, which might look better than the soffit type vents.

Frank

[NavyNJ]

Along the lines of dealing with the garage environment, rather than the original topic of "attic fans", what are the pro's/con's or consensus opinions on the garage screens that seem quite popular in many areas of TV? Not asking about which style of garage screen, sliding or roll-up, but just the idea of how a screen helps vs all of the garage ceiling fan options being discussed.

[mixsonci]

I think insulating the garage door is a good idea. My garage (when the house is finished) will face West and get the full afternoon sun. What is the best way to insulate the door? Also, how do you install vents in the garage door? Can the material be purchased at Home Depot? I would love to cool the garage down since I expect to spend a lot of time there.

I used Brit Killinger. A nice couple that does this all over TV. Their business card states "NASA Based Technology Polyethylene Panels" for the insulation and they cut out and installed the vents in the lower two corners. The cost was only $259 installed. His number is: 352-674-9303

[paulascorpio]

I was told by a contractor to insulate the garage doors and that this would be much more effective.