Thanks for the great presentation! I'm trying to avoid blown fiberglass and cellulose is what my HVAC guy suggested; this helps to make even more sense.
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.
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!
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.
I bought my multi level (1960) back in 2011 here in Pittsburgh. At the closing the son of the original owners said to me that his mom could never get warm in the house. The air leaks I found over the years and sealed I can understand why the poor woman was always cold in the winter. Most of the leaks were caused by the builder and other contractors who worked on the house over the years. It was bad folks the amount of various air leaks went from minor to major were plentiful. The worst area in the house that I thought was going to be an hour to an hour and half job was air sealing the garage and the stairwell up to the next level. That section alone was a seven to eight hour experience. I'd find one leak, look up, right, left or behind me and find another one. I really hate the builder and anyone that drilled and made holes in that part of the house. They'd cut a hole then just stuff insulation into it instead of fixing it right. Drill a hole and run a wire but not seal up the hole around the wire. If you have the time to do it yourself, plan on spending a lot of time over a number of weeks if you have an older home. It's not an expensive job, your looking at $100 to maybe $300 in supplies and tools to do it yourself but expect to rack up a whole lot of hours. It's not so much sealing the leaks, it's spending the time hunting them down, then finding a solution to seal it up. If time is not on your side because of family, work, age, hire someone to properly air seal your home you'll be glad you did. Plus most states and or power companies, offer generous rebates to home owners that have a certified energy efficiency companies seal and insulate their homes.
I've been trying to find the perfect video for my attic knee walls and this is it. My rafter bays were completely insulated with fiberglass all the way up to my ridge vent with no baffles. What is your suggestion to fixing this? I may of already pulled down 2 rafter bays of fiberglass to make an escape route for the extremely hot air. Edit: I have soffits and a ridge vent but no airflow
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.
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.
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.
whether you have a ridge or passive gable end vents or powered gable end fans, if you have proper soffit intakes gown low, you arent going to be drawing air from the living area. its the absense of intakes that makes ridges not work and powered fans to suck ait from inside the house.
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.
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.
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.
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.
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.
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!
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.
Add to my to-do list: Go in attic and check for dirty insulation. My house has a 3.5 ton system and really ought have 2 systems. There is a big temperature difference between floors in the high heat of summer.
I had a new roof installed on my house last year, and had significant changes made compared to the old one...first, they created a ridge vent, and second, I went with light grey shingles as opposed to the dark blue ones before, (which basically became almost black over the years), but I had the attic fan re-installed. I have a big, easy-to-read outdoor thermometer in my attic and I have found the difference between the fan running and not running on hot days is about 8 to 10 degrees. Worth it?...I think so.
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.
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!
That's a great point that most people aren't aware of. I've also found that a severe thunderstorm can lead to water intrusion if the wind is just right.
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 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.
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.
I'm not good at math, but my understanding is this: it's not the temperature of the attic air causing the problem. It's the giant solar collector called the roof absorbing radiant heat, then transferring the heat down the rafters and walls.
I’m good at math. A 250 cfm fan will do a full air exchange in a 2000 cu ft attic once every 8 minutes. That’s 15 air exchanges every two hours. Go sit up in an attic for two hours on a hot summer day, and then tell me you don’t wish you had a fan.
@@FFL-vg9ro Even though an attic exhaust fan can incrementally lower the temperature of a very hot attic, using a fan does not stop the source-radiant heat. During the day, any cooler air brought in by the fan will be heated up immediately by the surrounding structure. Most fans cannot keep up, because Physics
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?
Exhaust fan with louvers in the ceiling sucking air into attic, and exhaust fan(s) in the roof or gables blowing the air out. Once upon a long time ago, I lived in an apartment that had that set up. The place would stay decently cool, except when dreadful hot and humid, without running AC.
I just think someone being told to do something should understand it enough to say "there's no vents for this to suck from" instead of taking money and asking no questions.
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.
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
im an electrician ,unfortunately i have to go in hot attics all the time repaired/replaced hundreds of attic fans. most of the time the motor will go bad froze up (hard to turn) you can bypass the thermostat and hook power straight to the fan to test it. when i replace everything motor,fan blade and thermostat,the thermostat has a bypass on it for testing fan
