Attic fan????

Does your house have soffit vents? After the fan issue is fixed you are going to need to tackle the issue of ensuring your soffit vents remain unclogged.

Once you get the fan going, you can install rafter vents to clear the way from the soffits into the attic. From the pictures of your attic it will be an easy and inexpensive job. Then place some R30 insulation over your ductwork. This will make a huge difference in the comfort of your home.

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I was going to put a attic fan in my house. Not a whole house fan, but the one to vent to the outside to keep the attic cool. But I started to do some research and I found a lot of internetsperts that say that the fan uses more energy than it saves. And if you don’t have good ventilation and a gas water heater, it could cause carbon Monoxide issues when running the AC. If you don’t have proper attic vents and run AC, you will pull your cooler air to the attic.

The test is this – is the upstairs celling warm? If so – add more insulation. If not – why do you care if the attic is warm? If you have an asphalt single, the surface temp can get over 150F in the sun. How is keeping your attic less than that going to help the lifespan of the roof? You will not cool the attic to less that ambient.

I read 6 or 7 blogs similar to THIS ONE

Rusnak_322 wrote: I was going to put a attic fan in my house. Not a whole house fan, but the one to vent to the outside to keep the attic cool. But I started to do some research and I found a lot of internetsperts that say that the fan uses more energy than it saves. And if you don’t have good ventilation and a gas water heater, it could cause carbon Monoxide issues when running the AC. If you don’t have proper attic vents and run AC, you will pull your cooler air to the attic. The test is this – is the upstairs celling warm? If so – add more insulation. If not – why do you care if the attic is warm? If you have an asphalt single, the surface temp can get over 150F in the sun. How is keeping your attic less than that going to help the lifespan of the roof? You will not cool the attic to less that ambient. I read 6 or 7 blogs similar to THIS ONE

I am going to refrain from saying too much. I have a habit of offering long responses that makes people go glassy eyed.

Let me just say this... That article is pathetic, and completely lacks understanding of building science on almost every level. Mr. Holladay makes his living by writing provocative things on his website that will titillate his audience, not by understanding building ventilation science. Basically, it is wrong.

Everything he has said negative about powered ventilators also applies to whole house fans (backdrafting, house depressurization, etc). His arguments have nothing to do with either unit. They are about a properly sealed attic, and whole building envelope design (which he basically fails to address). Looks to me like he is getting a big kickback from Tamarack to push their whole house fans (BTW- they make attic ventilator fans too).

A whole house fan installed the way he describes breaks the building envelope, and necessitates a poor transfer of humidity from conditioned spaces to unconditioned spaces- bad idea.

That website is apparently owned by Taunton Press, a company I greatly admire. They offer some of the finest products on the market for building information. However, they are notoriously lacking when it comes to information on building sciences for southern buildings, high humidity locations, and areas where the cooling season exceeds the heating season.

They fail to recognize some of the challenges facing building science in the humid south. For example, the warm humid side of the wall is not the interior, a very small percentage of houses in the South use combustible fuel appliances, and A/C ducting must go somewhere, and most existing houses have it in the attic or crawl space. Your "warm ceiling" test sounds nice, but has no relevance when part of the attic is being used to move conditioned air (ducting).

SouthFace Energy Institute is a much better resource for building science information for southern buildings, or perhaps the work of authors like John Krigger.

The fan argument presented in that article is grossly over-simplified. It is a building sciences question that requires a much more holistic approach than most people are willing to give it.

What is true about the article is that most houses have poorly designed envelopes and fail to manage ventilation well. Unfortunately, the article fails to try to address the problem.

Rusnak, the information was probably adequate for you. You live in the north, and will not be adversely effected by the article's misinformation.

Octavious lives in TN. He has different issues than you do. The attic fan CAN be a benefit, but will need additional effort to make an adequate envelope.

Well, it's official. I have officially blown it again and had a bad case of diarrhea of the mouth. And I didn't even get into specifics. My apologies, gentlemen.

Well I appreciate all the responses...

Thanks guys

SVreX, for what it's worth, I read everything you post about buildings and follow up with your sources. Always good reading, and in regards to subjects like home comfort and efficiency, following some of your advice has both made my house more comfortable and has dropped my power bill.

Ramble on.

+1 to Derick's post. Please elaborate for us South dwellers.

I tested the fan. I have power going to the control unit where the twist caps are. But I have no power going up the twist cap wires to the control unit.

I also do have ridge vents. I took a pic but photobucket isn't working for me right now.

I did not see any other louvres or openings at the other end of the house.

The insulation near the bathroom vent fans has been pushed back. There are no boxes or anything around the bathroom vent fans.

On the side of the house with the bedrooms the soffets do not appear to be blocked. They do not appear to have insulation crammed down between the trusses on that side.

Lastly, one of the large are hoses that leaves the unit to go to the train room, goes up 2 or 2.5 feet to clear an area and then drops back down on the other side.

I will try and get the pics up and working tomorrow.

To what I was taught the thread title doesn't match the contents. I was taught as a kid that an attic fan is in the ceiling and draws air into the attic, mostly used in old houses that don't have A/C. I have family with old farm houses with this type setup. Like 1900 old.
Gable fans are what I was taught that this thread is about. But I can see that updated could be called attic fans as that is where they are and what they cool. And very old farm houses without A/C aren't really very common anymore.

Wlkelley3- my bad. I didn't know there was a difference between attic fans and gable fans until this thread.

I have softer vents. I can see them from outside. I will check and see if they are blocked

octavious wrote: I tested the fan. I have power going to the control unit where the twist caps are. But I have no power going up the twist cap wires to the control unit.

I don't understand.

Power at input end of thermostat, but none at output? Then the thermostat is bad.

Power at twist caps, but none inside the thermostat at the input end? Then the feed wire is broken.

Either one of these is a pretty easy fix. If you can test the power, you can replace the thermostat.

In reply to octavious:

OK, so the natural flow of ventilation in your attic should be in through the soffit vents, and out through the ridge vent.

Make sure your soffit vents are not blocked, but also make sure your ridge vent is not blocked. From the inside, you should be able to look up through it and see light, but also see if the the tar paper, etc. is partially blocking the opening. It is pretty common for ridge vents to be installed with tar paper never being cut away to allow air flow.

In reply to octavious:

After you've got the natural air flow working, you can worry about the mechanical vent (attic fan).

The article you posted said one of the problems with an attic fan is that you never know where it is drawing air from. That's not really true. It will always draw air from the path of least resistance.

If your vents are clear, this SHOULD be from outside. Unfortunately, that's not always the case, because 90% or more of houses have a terrible separation between the conditioned and unconditioned areas of the house. They need draft sealing.

A/C ducting, bath fans, range hoods, electric outlets, furnace closets, recessed lighting, kitchen soffits over cabinets all contribute to poor draft sealing.

You can visually check each of these items, but the best way to properly check draft sealing is with a blower door test.

I'd do both. First I'd visually check, then I'd hire a blower door test.

If the house is properly draft sealed, the attic fan will pull from the soffit and ridge vents, lowering the temperature in the attic, and creating less load on the A/C system. This should ONLY be used when attic temperatures are extreme. The thermostat set on 60* is certainly a waste of electricity.

octavious wrote: We moved about 3 weeks and have been having upstairs cooling issues. Had the a/c checked and unit is working. Tech said the attic vent fans are not working. Of course they aren't covered by the home warranty... Who replaces attic vent fans? And does anyone know what I am looking at coat wise?

I just re-read your original post.

I'm not sure I agree with the tech.

Do you have 2 A/C units or 1?

It sounds like you have a BALANCING problem, not a ventilation problem.

A properly running A/C system should be able to cool the house whether or not the ventilation is working. It might cost a fortune, but it still should be capable.

The attic vent fan is not part of your A/C system design.

I am betting you have only 1 A/C unit. It is designed to cool the downstairs, and the upstairs is just a bonus area, with ducts tapped off the main cooling system.

If this is the case, you are going to have a VERY difficult time ever balancing the system if it is a single zone system.

Do you have more than 1 thermostat? If not, it's a single zone system.

The upstairs is always going to have more cooling demand than the downstairs. If the thermostat is downstairs, it won't call for cooling when the upstairs needs it.

Get a new tech, then start saving for a small 2nd unit for the upstairs.

Svrex 2 a/c units and 2 thermostats. One up and one down.

I think the thermostat in the attic being set at 60 was to see if it work and kick on. It doesn't.

Let me try and clear up what I tested. I tested the wire going from the house into the twist caps (I don't know what they are really called) under the attic thermostat, it had power. However when I tested the wires going from the twist cap to the thermostat I had nothing. I agree that it might be a bad thermostat and I am starting there.

I thought this was about Attica. It was a riot but Sing Sing has a better view.

octavious wrote: Svrex 2 a/c units and 2 thermostats. One up and one down.

Ok, that's good.