AC Efficiency? - Page 1
Forum section: electronics / general

author: IonizedGears
author_rank: Regular Contributor
timestamp: May 31, 2013, 01:41:09 am
content: In my house there are 3 thermostats: One in my room, one for second floor, and one for the first floor.>My parents wont let me turn on the AC in my room because they think it wastes a lot ofmoney(High temp, high humidity here in Connecticut, USA).>There is a main furnace/ AC in the basement that pretty much powers the entire temp control in the house for each of the three thermostats.>My question is if AC was for instance, on for the second floor, would it make much difference at all to turn the AC on room in terms of using oil?>Normally i wouldn't ask this here but nowhere else really to ask. :/

author: Rick Law
author_rank: Super Contributor
timestamp: May 31, 2013, 02:17:07 am
content: Quote from: IonizedGears on May 31, 2013, 01:41:09 amWhere the AC machine is placed should have no impact. Do you mean the AC air-duct outlet instead?Cold air sink, so if there is no other means of circulating air, your bottom floor will be colder than the top. It makes the some sense to have cold air outlet at the very top of the house. However, without circulation, say you are on the middle floor, your body may be hot while your feet are cold as the cold air from up stairs very quickly find it way to the middle floor's ground where it will stay long enough merely to find it's way to the bottom floor.Had houses been designed by with basic physics in mind, every house would have a giant vertical air duct, pushing near-ground cold air to the top floor in the summer, while in the winter, it reverses direction and push warm air down. (Longest sentence award nominee...)

author: IonizedGears
author_rank: Regular Contributor
timestamp: May 31, 2013, 02:27:31 am
content: Quote from: Rick Law on May 31, 2013, 02:17:07 amI was talking about have the AC turned on by the thermostat, not it actually being on said floor. I was talking about having both thermostats running AC and how it shouldn't really change efficiency from having one thermostat pumping AC or having two running since the furnace is already running. But i am not sure if that is true or not so which is why I asked on the forums, I know physics already but that isn't really what i asked :/

author: IanB
author_rank: Super Contributor
timestamp: May 31, 2013, 04:40:24 am
content: Quote from: IonizedGears on May 31, 2013, 01:41:09 amQuote from: IonizedGears on May 31, 2013, 02:27:31 amJust a minor point of clarification here before we get to the serious stuff. You understand that furnaces burn oil or gas to make heat with hot flames right? An AC unit is like a refrigerator that runs a compressor using electricity. No oil burned. No flames.Quote from: IonizedGears on May 31, 2013, 02:27:31 amYes, well, I'll take that under advisementBut anyway, onto the serious stuff:Each "space" in general requires a certain amount of energy to cool it down. In this case a space could be a room, or a floor of a house. Regardless of where the central AC is located, adding more space to the cooling demand will increase the power requirement. So yes, turning on the AC in extra rooms will use more electricity. However, as you add more and more rooms to the house, the increased cooling requirement becomes less and less. This is because a cool room next to a warm room will help to cool the warm room. The best way to use a house AC is either to cool one or two rooms, or to cool the whole house. Cooling just half the house is probably the least effective way to go.