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Best use of fans?

makken

Golden Member
So temperature inside my house is 78; outside temperature is 65. There's no point in using the air con in this situation, and I have 4 fans available to me. Whats the best way to use the fans to cool down the house quickly?

Pull? (fans blowing out on southside windows, northside windows open)
Push? (fans blowing in on northside windows, southside windows open)
Combination? (2 fans blowing in, 2 fans blowing out)

ambient wind is negligible.
 
I always figured fans didn't really pull air from behind, but rather from all around it, so it wouldn't really draw air through the window, it would just circulate the air already in the room. Unless you were to make it into some kind of wind tunnel.
 
Make sure you turn your fan off before you go to sleep, else it will kill the hell out of you.

wat?

I always figured fans didn't really pull air from behind, but rather from all around it, so it wouldn't really draw air through the window, it would just circulate the air already in the room. Unless you were to make it into some kind of wind tunnel.

hmm, hadn't considered that. would see that that would favor the pull config. though I could wrap some stuff around the sides to make a wind tunnel 😉
 
Use the fire dept. method of ventilating a space to get rid of smoke and heat after a fire. (Not cutting holes in your roof to let the hot gasses out, lol.)

Negative-pressure ventilation is similar to power venting because it creates a lower pressure condition at an opening, which gives air flow a path in and out of the structure. However, the method used to create that lower pressure is different. Instead of using water from the hose, an electric fan is placed in the opening, blowing out. This creates lower pressure in the immediate area around the fan and allows for the heat, smoke, and combustion products to be drawn past the fan, following the path of least resistance out of the building. For greater efficiency, place the fan high into the opening; seal any empty space with some type of covering, usually a salvage cover, to prevent recirculation. If fire is still burning within the structure, this method will also draw it toward the exit. Again, do not use this method as the primary means of ventilation. It also requires more setup time and staffing because you must place a hanger in the opening, establish a power source for and stretch electrical cords to the fan, and cover the remaining opening with the salvage cover. In most cases, you just hang the fan and turn it on, making it less efficient.

Make sure the fan is back far enough so that the wind can be felt all the way around the opening, otherwise you will just create eddies and it's not going to work properly. BTW, make sure to open windows on the opposite side of the house for cross ventilation.
 
So temperature inside my house is 78; outside temperature is 65. There's no point in using the air con in this situation, and I have 4 fans available to me. Whats the best way to use the fans to cool down the house quickly?

Pull? (fans blowing out on southside windows, northside windows open)
Push? (fans blowing in on northside windows, southside windows open)
Combination? (2 fans blowing in, 2 fans blowing out)

ambient wind is negligible.

Although I think the very best would be push pull 1 fan blowing in 1 fan blowing out + 1 fan blowing directly on you. Or just the last if it's not too hot. I have the fan blowing straight on me right now.
 
Use the fire dept. method of ventilating a space to get rid of smoke and heat after a fire. (Not cutting holes in your roof to let the hot gasses out, lol.)



Make sure the fan is back far enough so that the wind can be felt all the way around the opening, otherwise you will just create eddies and it's not going to work properly. BTW, make sure to open windows on the opposite side of the house for cross ventilation.

ah, good stuff.
looks like pull it is then, thanks.
 
I've always done all in, the drawback is that the air can escape back through the same window that it was pulled in through unless it's covered someway to prevent this. Doing a combination of in and out will keep the pressure equalized within the house as long as they are similar fans and will make the air exchange the fastest probably.
 
Although I think the very best would be push pull 1 fan blowing in 1 fan blowing out + 1 fan blowing directly on you. Or just the last if it's not too hot. I have the fan blowing straight on me right now.

My computer is right by a window, so i'm gonna get some nice cool air blowing at me regardless of whether I have a fan set up directly there or not 🙂

I was originally favoring push/pull, but it looked like that setup was going to short-circuit pretty bad (ie. the cool air going straight from the push fan to the pull fan) I wanted to promote a little more turbulence inside the house so that most of the hot air gets exhausted.
 
I'd bet that 4 blowing in, with a couple of extra open windows, would be more effective than 2 in/2out.
 
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2 in, 2 out.

wat?



hmm, hadn't considered that. would see that that would favor the pull config. though I could wrap some stuff around the sides to make a wind tunnel 😉
Koreans and Japanese have this myth. See, fans, they make you feel cooler, right? So they think that if you do this for too long, then the fans cool you down so far that you get hypothermia and die.
 
Open windows on lower floor and on upper floor, natural heat flow FTW. Though fans can be used to accelerate this process.

Idealy, the best way would be to have water being pumped to a radiator outside with a fan blowing on top of it, and inside the house another radiator in the furnace plenum. A set of thermostats would activate the pump if the water outside is colder than the water inside. This way you gain the same humidity control.

Often the weather drops when it rains, but the humidity goes up, so it's almost worse to bring that air indoors as when it warms up it will also be more humid.
 
Ideally, turn on exhaust fans in kitchen and bathroom, then put box fans right up against the windows facing in. But the effectiveness of this varies by how your house is laid out and how powerful your fans are.
 
2 in, 2 out.


Koreans and Japanese have this myth. See, fans, they make you feel cooler, right? So they think that if you do this for too long, then the fans cool you down so far that you get hypothermia and die.

Heh, reminds me of a Chinese roommate I had. He told me it wasn't healthy to sleep with the window closed, because I'd run out of oxygen. I guess there's no winter in China.
 
I have box fans sitting in the window sill with the window shut down on top of it. Pulling cold outside air in.
 
google for swamp coolers.
Or take examples from old home designs. They were built with windows directly across from each other and front doors that lined up with back doors because in summer you could open windows and doors and have air moving through the home. Not like new homes where they couldn't be fan cooled if you wanted to.
 
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In summer I just get a fan and point it at my body, I don't care about cooling the house, it's supposed to cool me instead.
 
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