Cheapest/most efficient method of home AC use?

I’m in the habit of turning off the AC when I leave home for a while, just as I turn off the heat in winter (up north I’d turn it down, not off).

I’ve been also turning it off for an hour or two at a time when I’m home, because it seems to me that it kicks on more often than really necessary. When the thermometer on the 'stat tells me that it’s 3 or 4 degrees warmer than my preferred summer temp, or I start feeling uncomfortable, I’ll turn it back on for a while.

Is what I’m doing saving any juice, or am I wasting my efforts? I’ve started wondering about this, and I can’t think of a better place to ask the question. :slight_smile:

What uses up the most juice is when the outside unit kicks on. You can leave the fan on inside (you know, when you switch it from Auto to On on the stat) and be ok for a while, as it doesn’t use the same amount of juice to run the fan. Running the fan also keeps hunidity down in the hosue. But if the outside unit isn’t on, it’s not using as much electric as it does when the unit is running and the compressor is working pumping that hot air out. So, leaving it off a lot does save you energy and money. Turning everything off saves even more.

I am a MD State Licensed HVACR Journeyman and my dad still has his own AC company, just as an FYI.

You might also try running the AC on just a high enough setting to keep down the worst of the heat and humidity, and then use fans to help keep you cool.

See these past threads for the answer:

and the one where I summarized them:

Stomping out a fire while it’s still small is also the most efficient strategy. :wink:

I get a 404 on this one.

Your response is comprehensive, but here’s something outside the OP to consider. Allowing a home’s internal temperature to spike also allows a rise in relative humidity. High heat and high humidity provide an ideal breeding ground for certain allergens, notably molds and mildews. Bad news for allergy sufferers.

That’s how I look at it. I keep the thermostat set at 75, and only turn off the A/C is the outside temp and humidity will be low for at least a couple of days.

I’m going to track the outside temp and number of times the unit clicks on for awhile, see what happens.

I think a lot of this depends on how well-insulated your space is. (“Well duh”, everyone says.)


I did several searches before putting the question up. Clearly, I needed help in formulating my search (not something I’m accustomed to). Thanks.

I forgot to add some variables. I’m currently living in Mississippi, one of the hottest & wettest states. I have asthma and multiple allergies and, as a chronic pain patient, it’s not a good idea for me to let the place get too far outside my preferred parameters, if it will take too long to get it back to comfortable.

Some advantages: The apartment building I live in is brick (but was built about 40 years ago, so insulation is nonexistent); still, brick is a great help, and windows are flush with the exterior. It has horizontal slat venetian blinds, which I keep mostly to completely closed (slats rounded sides out). In the living room, which has a triple window, I have white curtains over the blinds, and heavy dark drapes (with white lining) behind those. I only have one layer at the other (3) windows, but the bedroom windows have heavy drape-like curtaining, fitted very close. At the kitchen window, I have four white curtain panels (2x normal).

I started with fluorescent bulbs in 1994, and use them in all sockets in which they can be used, and use the other lamps sparingly to almost never. I also have the advantage (for both heating and cooling) of living on the first floor. Wall with bedrooms is on the east side, but sun, etc., exposure on that side is mitigated a bit by nearby trees. Living room & kitchen face west, but a building projection obstructs sun on the kitchen window until at least 2 pm in summer, and on the LR windows until an hour or so later. My apartment is at one end, but it is not exposed, as the building is L-shaped - there’s only a narrow walkway between my end and the next section.

The only energy gobbler in the apt is my computer, but it’s probably on for 6-9 hours per day. I have a CRT monitor that I do turn off as I get up when I leave the computer and it’s on, with Energy Star mode set to turn it off in 10 minutes (less is a pain, if I’m watching a video). I have a TV, but it’s been unplugged for years. Music is on the computer.

I’ve tried to do everything I can within reason to reduce my energy consumption. These apartments are all-electric (first I’ve ever lived in), which freaked me in the beginning, but I think I’ve adapted.