ac

[el__marcin]

I have a small studio - around 650 sq feet. I try to ask about energy economy using my central air. There are two conflicting theories

1 Theory that most people follow : keep the ac all the time - when you leave, just increase the temperature

1. Theory that I follow : when I leave I switch it off completely

Please tell me who is right ? Explanation for my (#2) theory : I understand that the central unit runs at the steady pace (?). It does not matter whether it is 95 degrees or 80 degrees in apartment ...once I set the temp to 75 degrees (when I come back from work) the ac will be blowing air at the same speed, consuming energy at the same rate. True it will take it longer to knock down temp from 95 to 75 (40 minutes ) than from 85 to required

75 (20 minutes). But ..assuming that you leave the apartment and set the tempt to 85 the ac will switch on/off multiple times during the 9-10 hrs period you are away from home which will in effect be longer (more energy consumed) than 40 minutes. Please provide me with some good information - am I rite on this ?

The reasoning might get qualified if

A) somebody had large, good insulated house and it would take him horribly long to knock down temp from 95 to 75. So I guess in this case it be better to just allow ac unit to switch off/on for short periods of time during 9-10 hrs you are away from home.

B) The ac unit runs at different speeds ..consuming more energy with higher spread between present temp in the apartment and requested temp.

[Goedjn]

C) The cost to run the AC varies by time-of day.

[Joseph Meehan]

Too many variables. It would be far easier to run it both ways and see what happens.

Was the central unit sized to handle the studio?

If the studio is only used a relatively small amount of time, I suggest adding a separate A/C for it so you only need to run it when it is needed. Of course proper zoning of the central unit could also work well, but that would be a rather small zone and it might not work well.

[Edwin Pawlowski]

Both or neither, depending on circumstances, length of time away, outdoor temperature shifts.

When you turn the AC off, the space will start to heat up. The furnishings, for instance, will absorb heat. This is known as "sensible heat". The longer things are warmed up, the more heat energy that will be absorbed. Once it reaches equilibrium, no more heat will be absorbed and no additional cooling will be needed to remove it.

Going out for a couple of hours? Leave the AC on. Going away for a few days, turn it off.

[bnlfan]

Either shut if off or get a control with a timer.

You can get a thermostat that you can set to turn the unit off and on at a certain time. That way, if it is off all day no power is used. Then 15 to 30 mins. before you are scheduled to get home it will turn back on and cool.

The fact is that anything that uses power is wasting energy if its not being used.