cool house overnight, partial answer

Tamarack sells a whole house fan that is 1000 CFM. They recommend it for up to a 2000 sq foot house, in places where summer temps get up to 95 - which is about what happens here - it does get above 95 F sometimes but rarely over 100 F in the summer.
Scaling down for my 640 sq foot upper story I'd need about a third of that minimum, or 330 CFM.
Laura
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I posted this reply before. For some unknown reason my news reader often filters out my messages so I can't tell if they made it. Apologies if it already did. 1,000 CFM is not a lot. Tried to find the fan you mentioned on Tamarack's site but couldn't find it??
Here is a tip. You can buy a cheap 14, 16 or 18" fan at Wal*Mart or Home Depot. The type of fan you set on the floor or a table that oscillates, NOT a box fan. They cost about $15 here. Take it apart and remove the base. Cut a piece of thin plywood that will fit in an existing window and cut a round hole in it about 3/4" larger than the blade on the fan. Remove the front of the blade guard and mount the fan by the outer edges of the guard, put the front of the guard on the other side of the hole. Nothing fancy, just drill some holes and wire it on. Instant window fan,. total cost about $20. This is important: Since all these fans have plastic blades, be sure to run the fan and be positive it does not vibrate before you start. If it does, return it and try another.
And they work well. If you know how to use a window fan. Try to find a fan with a three wing blade. I have found very good 18" fans on sale at Big Lots and Home Depot. As the fan blade gets larger the size of the window it will fit in naturally changes too. Here in Tucson that's a problem in newer houses.
If you're lucky enough to have an attic, you can mount it in the access hole and cool the attic at the same time for free. However it's easy to make a much better fan for that use.
Al
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snipped-for-privacy@adore.lightlink.com (Lacustral) wrote:

A cheap box fan, some cardboard, and some tape to hold it together, but not to the painted walls! should get you going.
At least until you can figure out a more permanent solution.
150 cfm is a fart fan in the bath. 1500 cfm is a small whole house fan.
-- If I had something witty to say, this is where I'd say it.
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We put in a whole house fan in the attic the 50's, and it did a good job, especially at night with the screen windows open, created a nice breeze. Then my mother would close the house up in the morning and open the windows again in late afternoon. But it still got pretty hot at times.
The main advantage to those is if there is a prolonged spell of temps over 90, it gets all that accumulated hot air out of the house at night.
If you can't have central a/c, that is the next best thing. I have 3 commercial fans, two large and one small. They work pretty well until it gets so hot they are just blowing the hot air around. Then I just hide in my one air conditioned room. We can't use swamp coolers in my area becaue it is too humid.
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I Love Lucy wrote:

IMO, a lot of how useful a whole house fan can be depends on where you live. For example, if you usually have high humidity combined with heat, then they aren't much good. You can cool the house off at night, but you are pulling in humid air, which is a big part of the comfort equation that a whole house fan can't deal with.
I agree that they are useful for folks with no AC. However, I see a lot of people that have AC considering getting a whole house fan to use part of the time. And IMO, for most parts of the country, that doesn't make much sense, because there are so few days of the year when it will really work well, it's just not worth it, especially since the amount of power it takes to run the AC those days is not huge. Plus, you then have the problem of trying to seal it off well in the winter, dealing with heat loss through it, etc.
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snipped-for-privacy@optonline.net says...

I'm in upstate New York where it can get humid. But the whole house fan does the job if it's under about 85 outside, or about 80 if it's humid. That's a lot of days out of the summer and just about every night.
We have through-wall A/C units for when it's hotter. Even then, when we get home, we run the whole house fan for a bit before turning on the A/C to blow the hot air out of the attic. If it's very hot, we do leave the A/C units on during the day on their thermostats. But the whole house fan is a good tool to have.
By the way, when I had attic access installed with pressed board and lighting for some storage, I also put a switch in the whole house fan circuit by the access door so that anyone going into the attic won't get a nasty surprise from another household member turning on the whole house fan. I looked into interlocking the access door, actually, but the switch was simpler and does the job.
Banty
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Banty (Banty snipped-for-privacy@newsguy.com) wrote:

I live in upstate NY too! Ithaca. I wanted to keep the house as cool as possible by passive means. I got the attic pretty well ventilated - may be putting more insulation in there, and I'm planting tall trees around my house. The fan isn't passive but I hope maybe all those things together will avoid having to use AC. Electricity is very expensive around here, also there's noise.
Laura
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I'm near Poughkeepsie. I lived in Rochester one summer, though; it definately can get hot and humid there.
All those plans are great. On trees, you'll need some sun on your roof, especially in winter (plant deciduous trees..) and not have them close enough to affect the foundation. I planted a maple six years ago to catch some shade on the west side of my house during those summer afternoons, but still let the west side of the roof see some sun some of the day during the summer and all day (well, whenever it's sunny) during the winter.
Whole house fans do have that fan noise. I don't find it much of a bother, though, and if there's more than the fan air-moving noise it's either unbalanced or the bearings are going.
Banty
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Banty (Banty snipped-for-privacy@newsguy.com) wrote:

New York is far enough north that the sun never gets directly overhead. So really tall trees, even if they are some distance from your house, can shade it well. I'm thinking of a horse chestnut, which casts very dense shade - more so than maples (yes I know it has to be planted a safe distance from the foundation, like 25 feet) Horse chestnuts also grow very fast.
Laura
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wrote:

I have way more trees than average shading my house (well the sides at least, see further down), and the house still gets hotter than you know what sometimes. The last two summers haven't seemed quite so bad, but then temps didn't spike and stay close to 100 for days like they have some summers, plus I had a new roof put on with vents which may help the attic from accumulating so much heat.
Still, whether it's humid or not, it gets pretty miserable when the temps get above 90 even with so much shade; however what really matters, I suppose is that not much of the roof is shaded due to the sprawling style of the house which probably makes a difference. The house is a darker brown shingle which probably doesn't help either as darker colors absorb more heat.
My biggest problem is that I can't throw all the windows open at night with the screens on like we could when I was a kid because it isn't safe any more almost anywhere unless you're armed; even that doesn't always help. When you can't have the windows wide open at night, it traps the hot air in the house for days. Sometimes I turn the powerful fans and try to get a wind tunnel going by sucking in on one end and blowing out on the other, but it isn't very effective when it has cooled down a little at night and before I close up the house and windows for the night.
Even running fans and one window air conditioner jacks up the electricity bill, but not as bad as my heating costs have been running the last two winters which have been relatively mild compared to how they get sometimes. But if you're going to be immobilized from the heat, it's better to just suck it up if you can and pay the higher costs and enjoy the summers more. The humidity makes the heat worse and central air takes the moisture out of the air as well as cools.
I started having central air put in; the initial cost wasn't all that bad, but was worried that my bills would go too high as I save in summer compared to the awful costs winter has become, don't want to go on the budget plan. But my box has to be completely redone, so I postponed it. Now that energy prices have risen even more, I'm resigned to probably never getting central air. Everybody in my neighborhood has it; they must make megabucks to pay those bills. They don't *seem* to have to sacrifice to do it, people with young kids even (which takes more out of the family income).
That's why it would be helpful to me to have an attic fan; they are powerful and can suck in air even if just a few windows are just cracked open a couple inches which I feel I have to do now.
One silly way I have learned to cope with the worst days when I don't want to be stuck in one air-conditioned room is to use a spray bottle and/or wet my t-shirt and shorts down in cold water. That helps until they dry out.
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Banty wrote:

I don;t know about you, but I think it can be pretty miserable even when it's 75, but the humidity is high. Plus, under those conditions, the amount of AC energy it takes is minimal. Under those conditions, I will turn the AC on and in just 30 mins or so, there is a big and noticeable difference.

That sounds like a good use.
If it's very hot, we do leave the A/C units on

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