Is this a physics question? I don't know.

[IrishAyes]

Though I recently told friends in another group that I'm dimming the lights for summer, my busiest season, something has come up that I need to ask about.

My whole-house attic fan just died. I count on it to delay the need for actual air conditioning, but it would cost me more to have an electrician replace the motor than it would to buy a new unit, which would also cost precious $.

As an, uh... uncommonly thrifty person, I've been thinking about buying one of those extra powerful barrel-type tornado floor fans, cutting out the need for an installer, but there's a question as to best placement. My house is 2-story with wide overhangs, so there's no problem about leaving all the upstairs windows open. Since I live alone except for 2 dogs and even sleep downstairs for various good reasons, a large fan on the floor would not be an undue inconvenience.

BUT the question arises, would it work better in the upstairs hallway, pointed in the same direction(s) or would it suck more air up from downstairs if I put it on the midway landing - pointed upstairs - where the stairs make a sharp right? And should I keep all the upstairs windows open but leave only one open downstairs? Would that create a stronger draft since no air will be going into the attic anymore?

[Curmudgeoness]

1. I cannot answer the physics question.

But I can say that it should not take long with trial and error to find the best situation.

You do not say whether you are, um, uncommonly thrifty out of necessity or for the fun of it and the satisfaction, but if you can afford to repair or replace the attic fan, you really should. The attic fans are situation in such a way to make them most efficient at cooling the house. But that is my opinion only....and I am also one who enjoys frugal living. But sometimes, money has to be spent to save money.

That, or learn how to repair the motor yourself???? (Sorry.)

[IrishAyes]

2. Well, with me....

It's a matter of nature and necessity. I don't mind spending to save, not being penny wise and pound foolish. But if I can find a way to step sideways and save, I will. One of the problems is that I basically don't enjoy any more interference with my privacy than I can reasonably avoid. I really enjoy being with people - somewhere else. Maybe part of it comes from too many years of the past spent having to put up with people in my home that I didn't care for. Now it's become one of those old fart habits. If I can take care of the situation myself, I'd rather. Not sure how healthy that is, but I'm old enough to be getting sot in my ways.

So I can't help wondering IF the tornado fan might do a fairly comparable job at far less trouble. If that turns out to seem to be the way to go, I'm interested in what I think is the physics aspect. Rather than bumble around experimenting, and then having to decide on the basis of my fallible impressions, I would like to consider the scientific route. If there's anyone to guide me, as I personally am flying blind.

I loved the attic fan, but it's something that when it breaks again, I'd be at someone else's mercy yet again. Also, one of my future plans is to put a solar powered attic vent up there, and they have a lot longer life span. Another problem: with a house this old, the upstairs hallway - not to mention the stairs! - is so narrow that it took me over a year to find a whole-house attic fan small enough to fit. And it lasted exactly 5 years.

Mind, I'm not complaining about the peculiarities of this old house. It has offsetting virtues such as an upstairs bathroom bigger than some NYC apartments. And the extremely narrow and steep stairs, which almost seem like a old defense system (think short doors), are the major reason most people tell me they passed on buying the place. So it stayed available for me, for which I'm thankful.

[Curmudgeoness]

3. LOL, I understand, I really do.

I also HATE to be at the mercy of contractors, to the point that I put up with so much that I should not put up with (like carpet with holes worn through---harvest gold, for god's sake). I have been going to fix so many things for so many years that it has gotten to be a joke. But I do occasionally require someone here....and I do tolerate it in short spurts. I also have an old house and know that there is wonderful things about it and real problems in other ways.

As to the fan, I can only suggest that it be facing toward pulling air out of the house during the day, and after sundown, it can be faced to blow air into the house. I have no a/c, so I do know that even on hot nights, the air coming in is rather cool. I sleep well with a fan in the window pulling air from outside-----as long as I wait till dark to pull outside air. I also keep the house closed up, especially the west facing doors and windows, on hot days. I hate it because I love to have the house all opened up, but it makes a big difference in keeping the house cooler. Situating the fan is beyond me but I do think the right position could be found within a day or two.....if none of us geniuses here can help you.

[digonswine]

4. Here is a belated reply-

think of your house as a sealed unit.
If that is the case-the hotter air is upstairs.
What you want is a way to suck in cooler air to replace the hotter.
My advice is--and this is from experience-
At the far end of your upstairs-that is, from the point furthest from your stairs--put a fan in the window facing outside. Seal this as much as possible.
If you want to cool the downstairs, shut ALL OTHER upstairs windows and open one or two first-story windows that are furthest from the stairs.
If you want to cool a single room-the directions for upstairs stays the same, but you only open the windows in the room you want to cool.
This is the same for up or down-stairs.
Do not expect an immediate result. You should feel the difference within an hour.
Feel free to ask any questions.

[IrishAyes]

5. Thank you

That is exactly what I shall do, even when I get the solar attic ventilator, which won't cost any $ to run, installed this summer or next. If inside temps above 82 force me to run the attic fan at the same time, and/or even the super-tornado fan also, I'll gladly do so before turning on the A/C downstairs. We're having a relatively cool late spring here, so maybe August won't be quite so hot as usual. This is the higher elevations of the MidWest, so there's a chance.

One thing that will help besides the extreme insulation and thermal curtains is where I can open that single downstairs window you mentioned: The house faces west, so in the worst heat of the afternoon, the downstairs east end, where that part of the structure was built around a slave cabin, gets less sun than anywhere else. That area of the backyard is in deep shade by 2 p.m. That downstairs east end is also the most insulated of all, therefore naturally the coolest. So I can open my eastern downstairs storm backdoor and the screen door will allow the very coolest outside air to be drawn in, then on upstairs to be expelled by the window fan, whole house attic fan, and if necessary also the eventual solar attic ventilator.

I'm also blessed with a deep wraparound front porch on the west and south sides downstairs, so that helps. I've grown spirea on those sides so thick and tall that except for winter, a person can sit in almost complete privacy there. Had to cut down a diseased oak tree in the front but outside the front fence I've replaced it with nearly a dozen rose of sharon and forsythia trees plus one redbud, none of which will get over 20' tall - they will soon provide another layer of shade. For winter outdoor privacy I'm about to run white lattice panels all around the front porch.

But thank you again for your suggestions. I can see where your solution to the power use would work best, now that you've explained it. Not only will I be more comfortable, I should be able to save a little more on the electricity bill, and that savings can go right back into my restoration fund. After the good front gate posts go in, I've got to get more interior work done. There's one room where most of the ceiling still drops big chunks of plaster w/o warning. As I've said elsewhere, just about another year of abandonment or rotten owners and tenants would've left this place unsalvageable. The things that a few people did try to do are not just incomplete and worn out, they were hideous to start with. For instance, they'd lowered the downstairs 10' ceilings with those dreadful white insulator squares which were starting to deteriorate and fall down. When I got rid of those in the living room, we learned that the house's original ceiling medallion was hanging by a thread and ready to drop down and kill me.

Hope I haven't rambled on too long here. Restoration of historic buildings has always been a passion of mine.