Whole house fan..
 

Well its been a very long time since ive been on here.. but with the summer upon us ive noticed that my AC runs WAY WAY to much.. so im looking into whole house fans to cool the house off at night..

First thought is just to start simple and buy a good low energy consuming fan for the attic fan to cool it off at night and keep it cooler during the day. Ive found this one that only consumes 30 watts but moves 1500CFM CLICKY

so what i want to do is find a way to data log the attic temp inside temp and outside temp just to see how much of a difference it makes..

ultimately i would like to have a whole house fan which is where this will end up.. originally my idea was to get there 3100CFM fan and do the whole house first but the 1200$ price tag is a bit much for me.. so im thinking about getting the "attic fan and see how it is and if its good then ill just get 2 or 3 more of those attic fans and put some duct work on them and use them as whole house fans seeing as they are a lot cheaper and they draw less power.. Or is there something im not seeing?

Thoughts? concerns?

That's a gable fan and isn't designed to be installed as a whole house fan. Whole house fans are different because they are designed to be installed on the ceiling and have louvers that shut when the fan is off to block air from rising to the attic when its off. Cheap ones don't shut and seal that well and aren't insulated. Ones that IMHO you really need to avoid having a sieve installed on your ceiling that lets air flow, especially warm air leaving the house in the winter are well sealed and have insulated panels that shut over the unit, or something similar to that, when its off. Those gable fans will not flow that much CFM if you are putting any type of resistance against their air flow, the CFM is essentially free flow CFM assuming that there is a good opening inlet that isn't restrictive. Attaching ductwork to these will cut your CFM and likely also raise the energy usage at the same time.

Good whole house fans that will actually save you money are expensive. Since getting a good insulated one that seals well are not cheap, I just went with using 4 box fans off of a guy on Craigslist for dirt cheap. I open the lower level window with two box fans blowing in on the downstairs shady side of the house and two open on the shady side upstairs and open the hot/sunny side upstairs window. This way you get the cooler air from downstairs replaced and pushed upstairs while being replenished with cool air and you get the full crossflow upstairs. Depending on your house configuration this might bring good airflow throughout your house, it works very well for mine. FYI, Newer Lasko and pretty much any other 20" box fan use about 100 watts at full speed. I disassembled one and was surprised to find that they are actually PSC motors now, which is more efficient than the shaded pole motor that I would expect in a cheap fan. I've tried just cross-flowing the upstairs but it didn't work as well and getting the entire house to move air. It might be more efficient to move air with two fans with one in each of the windows instead of two in each window but for me that means I need to put up plastic to prevent the air from backflowing out instead of turning the house into a duct.

The reason I'm suggesting this is that I had a whole house fan in the house I grew up in and two box fans pulling air into a room with an open door will move about the same amount of air through an open doorway as a whole house fan does, without the expense of getting one that won't cost you more in infiltration and lack of insulation.

i understand the back draft damper.. there are places that sell them pretty cheap for none insulated ones.. i just figured i could go up there when it starts getting cool out (no longer use house fan) and put some insulation over the house fan just to block it off for the winter..

Tamarack...... all you need to know.

I installed an attic fan this spring. I don't have any data, but I would recommend to everyone, even with AC, to install one of these. Upstairs temp on similar days was -5c once installed.

Some more EcoRenovator discussion on WHFs and automating here:
http://ecorenovator.org/forum/renova...house-fan.html

Well I pulled the trigger on a fan today.. Found a site that had it for 15% off free shipping and no tax... Couldn't pass it up.. Ended up going with the quiet cool es2000 moves 2000cfm at less than 90 watts.. It's not big enough to do my whole for say but it's good enough for now.. I think when I get the second one I'm going to make a controller to run one or both depending on air temps... Anyway I'll update when it gets here and all that good stuff'..

Did you get just the fan, or the whole deal with insulated and automatically actuating damper?

I got the whole thing

Sounds great. I look forward to hearing about the install and how well it works.