Is a Roof Power Attic Fan a Waste of Money....or Even Worse? 

As a roofer I can confirm most roofers don’t understand ventilation. They think more ridge vents, slant backs, turtle vents, etc solve every issue. I recently ran into one (thank god Allstate covered it) which was blistered so bad on the 2nd story roof that finding hail damage was almost impossible. It was a 14/12 pitch which meant 1 slope was shaded at most times of the day. The customer told me the AC would never turn off in the summer and wouldn’t cool. They upgraded their AC twice and still no luck. They had gable vents, ridge vents, turtle vents AND turbines. It was only venting the top 2 feet of roof. Below that 2’ line and down was purely blistered shingles, and they had soffit vents caked with latex paint. 4 different types of exhaust vents and virtually no intake. Once I did his roof he called the next day totally over the moon because his AC finally cooled the upstairs bedrooms and shut off.

I live in the south eastern US and these things are a must as is soffit venting and ridge venting. In many places here soffit venting and ridge venting are governed by building code. They also help your roofing shingles last a little longer as well. FLY NAVY!!!

I love the word “passive” so much when it comes to home heating and cooling.

I wired a fan for our attic after a carpenter installed a fan near the roof peak, but I never considered where it got it's intake air from! There are just small vents at either end of the attic! We found that the fan didn't help keep the upstairs cool,so it wasn't used after that. Thanks for pointing out something nobody considered as far as intake air was concerned!

Andy, the bashing of some (many, most?) roofers, many of whom do siding as well is warranted. Couple quick examples from neighbor, combo of house flipper and pros hired by new owner… soffit vents blocked by attic floor insulation; gable vent blocked by plywood sheathing; roof gutter level, NOT pitched toward downspout; and (opposite side) reconfigurated gutters to drain to lower roof and use it’s downspout ruining 1st floor ceiling. Neither roofer nor (inept) town inspector anticipated the problem they caused. Re: power fans… some may miss your note in the comments that in right circumstance, done right mechanical fans are BETTER. Clearly, many got the wrong impression. BTW another pet peeve is over-sizing AC units by contractors… big units quickly cooling do not adequately remove humidity which is the prime source of discomfort. End rant 😀

I put 64 bags of blown in insulation in my attic where 40 were recommended. I have a pea gravel roof where I cemented the pea gravel to four layers of 30 wt. tar paper. After a few years I removed all the loose gravel power washed the gravel and applied three layers of white elastomeric. I have reapplied the rubber every few years because it gets dull and dirty. Now my one of a kind roof is hermetically sealed , even hail cannot penetrate. My utility bills are low I mean really low.

how do you blame the roofers for no bird block vents or eve vents ??, Thats a load of B S unless they framed the house

A ridge vent & soffit vents are really all that is necessary. Let simple science work FOR you. 🙏❤😇

Beware of the ridge vents in areas subject to hurricanes! One family had the ridge vents and the wind was blowing water UP the slope of the roof where it entered the vent and flooded their house! There was no other damage to the house, only the water damage from that damn ridge vent!

This video didn't consider the gable ends of the attic. No need to cut any holes in the roof that can leak. Just use the gable ends for vents. And an exhaust fan on one end would be great for summer heat.

Our house was built in 1995. We originally had an attic fan added to our attic at the time of construction. We do have two gable vents on the side for intake (we're an end-unit townhouse). Now, after about 10 years of so, the attic fan motor blew and we never replaced it. Finally, in 2021, we had our asphalt shingle roof replaced. We had the roofing company hack saw off the exhaust vent, cover the hole with plywood, then they put in the new roof. It looks smooth, and you cannot tell there's an attic fan, unless you go up into the attic. Of course, we won't do an attic vent now, as we have solar roof panels installed over the back slop of our roof.

Thanks for that explanation. We have a power roof fan but it quit working a few years ago and I left it that way.

Older houses, like mine, have an attic fan that pulls air through windows and blows it out through the attic vents. This cools the house and attic at the same time. When using the AC the attic gets hot because it's natural air flow doesn't keep up. I think I'll put a couple of wind turbines on the roof like our old house in Louisiana had. On that house I cut an 8 inch wide strip in the soffits all the way around and covered it with 1/4 inch hardware cloth. It breathed very well after that.

This is such a simple demonstration and explanation, well done! I’m about to be a new home owner and the attic has always seemed so intimidating. At the very least, this helps me better understand how attics can be cooled. Thank you!

Great video. I had one installed but quit working and I worked on the wires by unhook them and hook the back. It is fairly new and love for someone have an answer to the problem. Thanks for sharing

Yes, great video, thanks!

For air to cool your roof space, it need to flow from somewhere cool like the soffit and exit near the ridge.

Good advice, thanks.

While living in the South the temperature in the Attic can get up to 150°. I have a two system house. The upstairs system is in the attic I have a vent on one side of the attic approximately 2 by 2 on the wall and on the other wall I also have a 82 * 2.0 with an attic fan attached to it. Since installing it I have reduced the temperature on my upstairs bedrooms by 8°. I noticed you live in Pittsburgh so this may not affect you as much but in the South attic fans are a necessity. If properly installed they can greatly reduce the heat of the upstairs rooms

The international energy code requires 1sq.ft of soffit ventilation for every 100 square feet of attic space . If you use as many Power vents as are required to vent your attic space you will use as much or more electrical energy as you save . Not counting the cost of the power vents and the labor to install them and there average life span is about 5 years. You need turbine roof vents or ridge vents or stand alone vents. Ridge vents that don't have baffles can leak from wind blowing in rain or snow. You need attic ventilation in the winter to help stop moisture that lowers the effectiveness for your insulation. When insulation gets wet its like putting on a thick wet sweeter on a winter day.

My dad had a gable vent fan that cooled the attic a little. Contractors sided over the vent opening, installed perforated soffits, ridge vents and powered roof fan; absolutely no cooling effect in the attic. Dad's gable vent alone was the most effective of all these efforts. Cannot find a contractor who will install gable vent/fan.

Nice concise video, thanks! I have a large solar powered fan I am getting installed and was thinking of foaming shut the ridge vent adjacent to the fan so it pulls air from farther away in my attic. I have a large gable vent at the furthest part of the attic so plenty of ventilation.

Mine worked perfectly. Home was cooled considerably in minutes.

Great video

Great video, I have the same issue in my attic. Any chance you can recommend someone in Cleveland, OH area? Thank You!

My house has the soffit vents plus 3 gable openings to pull in cooler air.

You are blaming the roofer at 0:48 - no, it might be the siding guy that did that. And the insulator should have stapled in some vent troughs before the insulation went in. Now, I don't know whereabouts this was shot, but there's inadequate insulation there, and the ducting should be insulated. We had a solar fan in the roof from the previous owner - didn't work, so I upped the insulation and we had a mini-split installed for the upper room - normally we only get 25° max, but occasionally it hits a high of 32°C and a low of minus 5°C... the mini-split keeps the missus happy.

My gable mounted fan is exhausting hot air from the attic. The make-up is coming from the soffit and the ridge vents. All my bathroom fans vent directly to the outside.

Thanks for the video! My roof is about 2500 sq ft, and it has 34 soffit vents, 4 gable vents, and a ridge vent above the living space. The garage has no ridge vent, and its the coolest part of the attic. It has a gable vent, soffits, and a roof turbine. Being that its the coolest part of the attic, I presumed the ridge vents are not working well. Its the honey comb style. I added a 3000 rpm smart gable fan on the opposite end of the home over the master bedroom. I am seeing improvement with attic temps by about 10 degrees with the gable fan. However, I dont want to interfere with the function of the ridge vents, even though I dont think they are working efficiently. My roofer also thinks they are not efficient and therefore no longer installs the style I have. Since I am questioning the effectiveness of our ridge vent, I am thinking about adding another smart gable fan on the other side of the home. What are your thoughts about this?

Andy, what do you do in older houses that may have blocking between the soffit area and the attic? Drill holes? I guess if the house needs a new roof anyway, under shingle vents are a good solution, though it seems you'd need a whole lot of those to equal the venting you could get from continuously vented soffits which would also be much more discreet. Love your channel!

Good overview. When I reroofed, they added shingle vents along the full lower roof line (as my soffits are too narrow for typical vents) and added a full ridge vent. Summer does cause the attic to get rather warm just from the normal full sun the roof receives. I'm wondering if augmenting the ridge vent with a solar powered fan (or two) would be of any benefit to pull some extra air through the shingle vents or if its a waste and the air would simply pull through the ridge.

Thank you for this video. Now I think I'm wasting my money with my powered attic fan. I live in Fort Worth, TX, in a 100-year-old, 1,500 sq ft bungalow with a simple gable-style roof with large gable vents at either end. I installed a powered attic fan near the ridge many years ago, thinking it would improve the removal of hot air from my attic in the summer. But I have exposed eaves, so I don't have soffit vents. So it is probably pulling conditioned air in through the many penetrations in the ceiling and walls of my home. Looks like I've got a big job ahead of me before the brutal heat wave gets here and roasts my house again this summer, starting with sealing things up well, of course. So, thanks again for this video!

I'm wondering if the power vent was installed prior to the ridge vent being cut in it a later time. In any case I agree with others that the fault likely does not lie with the roofer. All other points made are dead on!

I was a home inspector for 30 years. Was the open elbow pointing up into the attic from an interior exhaust fan? Certainly appeared like it. That's a big no no.

Hey dude Roofers don’t install the gable vents or soffit vents. While they do install the power attic vents it’s already tacked in place and they have no choice but to install them.

How can a ridge vent work under heavy snow? Vent buried, limited soffit vents in my house.

good

As a Homeowner: another example of idiots working on a House and no one to monitor nor control the mistakes

And the air that the attic fan pulls from you house has to be replaced some how so hot moist air is drawn in from outside increasing the load on your AC system.

They work great ridge vents suck.

I don’t use AC at all. I’d like to suck out the hot air from the house itself. Hot air pools near the ceiling. Does it make sense! What’s the best way to do that?

Dupont has a 2hr video in how attic/gable fans cause more trouble then help

Been using a pair of turbines for 3 decades..............not a watt yet.

If your good at math it does not take much effort to figure out attic fans do not provide enough air flow for temperature management. The point behind attic ventilation is moisture control. To keep the humidity as low as possible. Then the next step is to ensure you have enough insulation of the proper type to keep your house cool. air sealing your deck is also very desirable.

How does an unseald space become “pressurized”? 😂😂😂

And most if not all people don't understand building science! Even the people that write the codes! Remember building codes are the "minimum" building codes! Fiberglass and Cellulose should be outlawed! They just don't work! Convection (air leakage) can't be stopped by loose fill insulation! And HVAC (Heating, Ventilation, Air Conditioning) 99% of the time is installed incorrectly! In your video you have equipment "outside" of the thermal envelope! If you insulate the "shell" of the home everything you do in the future is "inside" the thermal envelope!

consider some more insulation.

Finish carpenters install soffit vents roofers roof. Power roof vents work, I know, I had one. You're mistaken on just about everything you said.

Would a gable fan work in this situation?

Ignorant is as ignorant does.... Forrest.

Hard to hear

Yup, there can be no exhaust of hot air if there's no intake of cool air. I disagree on the insulation thing, the hot attic, if not properly ventilated, will still "heat soak" down into the house. My house in Cleveland had minimal venting and it was literally impossible to add more to the soffit, so the fan I installed helped, but not enough. It was hottest in the house in the evening AFTER the sun went down as the heat energy came down. You could feel it when you went from sitting down to standing up and your head got into the warmer layer INSIDE the top floor. I don't think even my new build house (2019) has enough vents. If I ever do a new roof, I'll have it done my way. My builder allowed no modifications like that to the approved plan.

I havs a solar powered roof vent fan.

whole house fan. Cools both the house and the attic.

I once read that the only way an attic fan would be effective at reducing heat is if it could move massive volumes of air -- along the lines of a small propeller-driven aircraft engine.

@1:50 As an expert, you lost credibility when you claimed the attic fan would draw air conditioned air out of the house. HuH?

Why do proponents of power roof fans never mention the fact they don't do anything for those in cold climates in winter. it's not good for a hot attic when the outside temperature is 30f and the attic is 70. Ice dams mold etc