Running Central Air Efficiently

[Psyche]

We've had exactly two adult years where we were responsible for utilities :bag both in an apartment. We never tried to be irresponsible users of the a/c but we didn't think anything of turning it on and off or using it if it was barely uncomfortable. And in MI, it is almost always humid so 80 feels hot. L

It would seem in TX that it is only humid when it rains. And almost 90 here is cooler than 80 in Michigan unless we are in the full sun.

In Michigan we also never got a good cross breeze ad here we do and are shaded from the hottest times of the day. :rockon

So our old a/c rules were over 80 during the day or over 60 at night. We prefer fresh air.

We turned the air on last night since rain was expected and it was supposed to be mid sixties. It's in the 70s now so we shut off the air and opened the house.

So how do we use the a/c efficiently? Is it better to keep the house shut up rather than turn it on and off? So we turn it on at night and just raise the tempt during the day instead of openin the house? Or is it better to turn it off and open the house during he day and shut it up at night? Does that make sense? What is most efficient? What is the best temp to keep it at night an d day? If the low is in the sixities and we put the termostat at68, should we just keep the house open? TIA!

[Saphirah]

We keeps ours on, it's more work to cool down a hot house rather than keeping a constant temp.

We have to deal with MN humidity though, I do like to keep the windows closed and ac running to filter out the pollen. We also have a power saver switch on ours so the power company can turn it off for 15 min in an hour during peak usage. I can tell when they are doing it too. But we get a discount for that.

Do you have a programmable thermostat?

[Starfox]

We get a good cross breeze here too, and the apartment stays cool. Once it starts creeping up to80, we'll flip it on. I wouldn't wait until it got up super duper hot, but within a 10ish degree range I don't think its bad to flip it on and off.

[Psyche]

We do not have a programmable thermostat but I think I want one.

[mamacat]

We open our windows in cool of day on dry days.Our therostat is set pretty high and we use ceiling fan in a room we are in

[klpmommy]

I've heard it costs more to turn it on and off. In all my TX years i have never actually seen that be the case. :shrug

Right now we are turning ours on for a couple of hours at night to take off the edge of the heat, then turning it off. We aren't running it daytime at all, just opening windows and running box fans to help with the breeze. We are very lucky that with a park across the street we get a better cross breeze than if we had houses across the street.

Our general rule is basically to keep it off unless we are over 90 in the day. By night we go by feel b/c the daytime temps make a huge difference in how cool it gets at night inside.

once we start running it constantly (it won't be long) we will set it to 81 upstairs and 79 downstairs and run fans during the day. At night it goes to 76/75. If we are going to be gone all day I will bump it up a couple of degrees, but only if we are going to be gone all day.

:shrug

[tigerlily]

Call your electric company, they may offer you a program to install a digital thermostat for free as long so they can turn it off for brief periods during peak usage times ( the terms of ours was very reasonable -- never on a weekend or holiday, never so long that the temp would raise significantly, fans run continuously even though AC isn't on).

Last year I heard or saw a list of common myths about AC efficiency. It stated that it doesn't take any more energy for your unit to catch up than for it to maintain a consistent temp.:shrug3

[MaryPoppinsIAin't]

Energy, maybe not, but I know from bitter bitter experience that if we allow our house to get up to 80 (or, God forbid, above 80), it takes DAYS for the central air to catch up and get it back down to a civilized temperature. Our blower is old and cranky and needs to be replaced because it has a tendency to make the AC unit work so hard that it freezes up and stops working entirely. The way we do it is we maintain the inside of the house as close to 70 as possible. If it's 70 or cooler outside, the windows are open. As soon as I see the reading on the thermostat hit 72, the windows get closed and the air goes on.

[Rabbit]

Yup. If the house gets too hot, we may just have to wait for a break in the weather to ever cool it back down. We will have 110 days, and I will water the outside brick after the sun goes down. The AC will struggle trying to maintain 78. Plus, it isn't good for your electronics or the produce that sits on your counters, like bananas and tomatoes, to get above 80.

[librarianjojo]

The maintenance guys at our apartment recommend choosing a temperature and sticking with it. It is easier on the unit over the long run to keep the home at the same temperature. A good rule of thumb is to keep it no cooler than 20 degrees less than the outside temperature (obviously you cannot do that on days that reach 110 ;)). This is what we do and we live in SC. Hot and humid does not even begin to describe the swamp that SC becomes in July and August. We still take measures to keep the temperature of the apartment down, like using fans, keeping shades drawn, minimizing the use of the oven, hair dryer, and dryer, and trying to get acclimated to being warm. (Pro tip: a fan blowing behind a drying rack of wet clothing is wonderful during days of dry heat. Your clothes dry quickly, your dryer doesn't heat up the house, and you get some cool, moist air moving around. :rockon)