Settle A Debate For Me (Drop Some Science)

[Suicane75]

Having an argument with a flatmate. He's got double windows, side by side that look like this.

[ ][ ]

In the right side he put in his air conditioner but is only using the fan part for now. Now, he closed the left window, saying that he's keeping the hot air out. It feels like a friggin convection oven in there but he swears that it's cooler than if he opened the left window. Am I wrong in insisting that the room would be much cooler if opened the left window?

[korme]

If it's only the fan then he should open the window

[Bobble]

This is similar to a discussion I seem to have all the time with my wife. Whatever temperature the air is outside -- even though it may feel "breezy" or "nice" out -- that is the temperature our house will start moving toward if you open the windows. If it's a beezy 78 outside and it's 74 inside, we shouldn't open the windows and expect to end up cooler.

[Julio Riddols]

It depends on what kind of roof is on the place in my opinion. My roof is a metal one, kind of rusty. It absorbs a shit ton of heat. I find that having a fan set in a high window with another window open helps pull or push the hot air out depending on the direction of the fan. That tends to produce a slow, steady cooling effect when it isn't just a really hot day outside. If it is really hot, I cover the windows with something as opaque as possible and let the A/C do the work with help from the ceiling fan.

[CraigSca]

The answer is - if it feels like a convection oven, turn on the AC. That's why he bought it, right?

[Suicane75]

The answer is - if it feels like a convection oven, turn on the AC. That's why he bought it, right?

Well we don't turn on the AC till everyone has theirs in. But he swears that it feels cool in there, at least cooler than if he had the window open.

[Suicane75]

This is similar to a discussion I seem to have all the time with my wife. Whatever temperature the air is outside -- even though it may feel "breezy" or "nice" out -- that is the temperature our house will start moving toward if you open the windows. If it's a beezy 78 outside and it's 74 inside, we shouldn't open the windows and expect to end up cooler.

So you're telling me the house will get warmer with windows open than windows closed? I'm not saying you're wrong, it just doesn't make sense to me.

[Alan T]

On a hot day, should you keep your windows open or closed? | Vancouver Sun (http://blogs.vancouversun.com/2012/07/26/hot-day-windows-open-closed/)


Seems to be someone else who asked the same question, and what he found.

[Bobble]

So you're telling me the house will get warmer with windows open than windows closed? I'm not saying you're wrong, it just doesn't make sense to me.

Not in your case, no. In your case, open the window. If you want more of the cooler air from outside in the house, then open the window and let more of it in.

I usually have the opposite situation. The house is a nice, cool 74 degrees (either by A/C or cooler night air) and the wife notices that it's "nice" out and opens the windows. It's "nice" out because a breeze makes that 78 degree air feel cool. I end up with a 78 degree house that I have to cool off again.