View Full Version : Ac and turning off thermostat Q, save or cost more
08-16-2006, 08:38 PM
Heat pump owned. Is it true that completely turning off the thermostat during the day, and then back on after say a 104deg day after returning to home after work, is counterproductive since recooling the walls and such will be energy hog, costing even more to operate? sid
08-16-2006, 08:48 PM
<blockquote><font class="small">Quote Sid_Vicious:</font><hr> Heat pump owned. Is it true that completely turning off the thermostat during the day, and then back on after say a 104deg day after returning to home after work, is counterproductive since recooling the walls and such will be energy hog, costing even more to operate? sid <hr /></blockquote>
I am not an expert in HVAC, but I have owned a couple of heat pumps in the past.
To the best of my knowledge, with a heat pump, it is best to leave your AC on all of the time, at a consistent temperature. Do not set it back and do not turn it off.
At least this is the recommendation that was given to me by several HVAC contractors.
08-16-2006, 09:16 PM
Thought I'd heard that same thing myself. Thanks...sid
08-17-2006, 06:31 AM
<blockquote><font class="small">Quote Sid_Vicious:</font><hr> Thought I'd heard that same thing myself. Thanks...sid <hr /></blockquote>
Sid, IIRC, the theory behind this is that a heat pump neither super heats nor super cools air. It works at maintaining a constant temp.
08-17-2006, 08:06 AM
In my former lives as a plumber and maintenance person at an apartment complex, we were always told to keep the temp the same, during the winter and summer. If you change the temp, don't do it drastically.
08-17-2006, 08:49 AM
All advice I'd mostly followed. Being that it's 106 almost daily, I hear those in chatter talking about school starting back and turning the ac off since nobody's there to cool, so I figured I'd ask again myself. Short of baking the cat, the ac being off would be logical, but I'll stick to your advice. Thanks...sid
I have always wondered the same thing. My thoughts are that it will save some money, but I don't think it is enough savings to force me to sit in a 90 degree house for 20 minutes while it all cools down.
Our power company used to offer a discount on your power bill if you would allow them to turn off your AC for certain times periodically throughout the day. We never opted for that. I did have an electronic thermostat put in that allows me to schedule the times for the AC to turn off and to come back on. It goes off at 9AM and back on at 4PM. That gives it about 45 minutes or so to cool off before I walk back in the door (and sadly continue to work from home /ccboard/images/graemlins/frown.gif)
Sid i think your better off setting it to 78 degs during the day (with curtains drawn)when it is really hot and maybe dropping it down to 74 when ya get home... that is what i do any ways. my place always feels cool and the power bill is reasonable.
BTW do you have dual zone temperature control?
08-19-2006, 06:47 AM
My AC guy said the same as Naz. Leave temperature at 78 during the day. He also stated that when the AC compressor kicks on, it uses a lot of electricity to compress the freon from a gas to a liquid state in the system. After the freon is compressed, the electricity usage goes down. He said that "ideally" the compressor should run a minimum of 20 minutes before shutting down (mine runs non stop here on the Texas gulf coast from about noon till after dark during the summer). He said it should run that long (min. of 20 mins.) to get the humidity out of the house. If you get a unit that is way oversized for your area, it will cool down much faster, but if it doesn't run long enough when it does come on, the humidity in the house will stay high and you have a chance to get mold and all kinds of bad stuff.
I am no expert by any means, but what he said makes sense.
A few years ago, I replaced an old unit that was with a high efficiency one. My electricity bill was literally cut in half. The unit paid for itself in about 2 and 1/2 years. Of course being on the gulf coast, we use the AC a LOT through out the year. It's not uncommon down here to have short and T-shirt on during the Christmas holidays.
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