The Great Household Debate of the Month.....

Invest in a programmable thermostat. You would shut the windows before you left and you could program the a/c to kick on 30 minutes before you got home.

Compromise! If you normally set the A/C at 75, then set it at 79 or so. That way, the house is cooler (assuming the house would be 85 if the A/C was off), but you haven't paid to keep it at 75 all day.

The air conditioner will have to work harder when it's already hot, and it will likely burn more energy in that process. Also, the humidity in the house will make it harder for the air conditioner.

So, I say turn it on before you leave in the morning. It won't kick on until the thermostat registers that it's approaching the desired temperature anyhow.

We have a cat and dog in the house, so we leave ours running all the time for their comfort......

Out of the two options I say turn it on in the morning.

We don't turn off our AC until those up and down days are over b/c it cost a lot to cool down a whole house (especially if one day it's on, next day windows are open, then back to being on). We just set the air to a certain temp and never touch it so it's always the temperature we want in the house. On cooler days, it might never kick on. Then when those up and down days are over, windows are open until it's time for the heater :)

I agree with turning it on before you leave, but maybe not at as low a temp as you usually prefer it so it's not wasting too much energy through the day. That way when you get home it's already on, the house is tolerable and you can just flip it down a couple of degrees without making the thing work too hard to make up the difference.

I totally get that at 8mo pregnant you want that AC ON! lol! Been there!

We just got central air. The technician told us that if it is going to be a really hot day, we cannot wait until noon or 2 to turn the air on...that the house is already too hot and the unit will not be able to cool it down. He said you have to nip it in the bud and turn it on early in the morning.

So #1.

The first option will actually be less expensive. If the house is already cool and you shut up the house & turn on the AC before leaving, the furnace/AC doesn't have to work as hard (use as much electric or gas) to keep the house at the temp you want.

If you want to split the difference, just do that, and set the thermostat to slightly higher than you personally want (if you want 72, go with 75, for example).

Also, I 2nd the idea of a programmable thermostat - they also help with energy efficiency.

We spent about $30 and bought a programmable thermostat my husband installed it in the hallway where the controls are located...then we just leave the unit on but program it to come on about 2 hours before we get home. Of course we live in Texas so it stays on 9 months of the year.

I vote for turning it on in the morning - it would seem to me that it is less work for the AC unit and you come home to an already cooled-down house. But I like Kaye's idea of having it set on, say, 75, and then turning it down to 70 or 72 when you get home.

I always win....especially pregnant. I'm always hot....so I keep it cool. He can put on more clothing, but I can't take anything more off.

In all seriousness....close up the house before you leave and set the thermostat to 79, so that it doesn't have to work SO hard when you get home. Bringing the house down 4 degrees vs. 10 degrees can make a difference AND it depends on how insulated your home is, as to how much extra work/money this is going to run.

My friends in Arizona keep their AC at 90 in the summer....when it's 120 outside and it NEVER shuts off it. If they turn it off when they are out, their candles melt and the poor AC can't get the house cooler than 110.

We have a programmable theromstat. WORTH the money.

I would also vote for turning on before you leave - who wants to come home to a hot house?

this debate is for another time. in our house if you're pregnant you control the thermostat.

K.

I just got a new furnace and ac. The manufacturer says it's more cost effective to turn it on before the house gets warm. I guess it's suppose to be easier to maintain coolness than to get cooled down after it is warm.

We've got the same "debate" about AC going on here....

Really you're better off (energy wise) to set it & leave it on.

On cool days, our house stays cool with the windows open most of the day til late afternoon--when you'd think it would get even cooler, right? Wrong! Our house gets SO warm and stuffy in the late/afternoon/early evening that I can't stand it. I just can't function in a 78 degree house. So I flip it on. Probably be wiser of me to leave it on throughout the day & forget it.

I agree w/PP--a programmable thermostat is worth the very small investment.

My husband leaves the air on, he likes it cooler. Nicer days I turn it off and open the windows. Then again I'm not pregnant.

I was home all summer and knew when the AC comes on. I think it would be sufficient to turn the air on about an hour before you arrive home. When you get home it may not be target temp yet, but it will be cooler than outside and the AC will be running. I think you will save a lot of energy and money by not having it on all day.

I vote for turning it on before you leave, just turn the temp. up a bit to around 80. That way its not running all day and it doesn't have to work so hard to cool the house down in the evening. Plus, you are 8 months pregnant, the last thing you want to come home to is a sweat pit.

my husband has been doing heat and air for almost 20yrs now. and he has always said that it is horrible to turn your air on and off. it has to work harder and can do damage to the unit. i suggest just leaving it on but turning it up when you are not home.

I never leave AC on when I am not there. And during the winter (and I mean deep Dec/Jan winter here in MN), I leave the heat on when we are out but set the thermostat down to 55 degrees.

I don't think it necessarily makes the unit(s) work hard to be on all day vs catch up when you get home. It is probably an equal energy spend. But I just cannot leave the house with those things chugging away. It feels like leaving all the lights on.

EDIT: We went the programmable thermostat route too but those things have a very limited life span. Expect to have to replace it sooner than you might think is cost effective.

Why don't you compromise by setting the AC setting to something like 77 degrees at 6:00am and then setting it to 72 when you get home? That way it won't be super warm inside when you get home but nor will it take 4 hours to cool down.

I do the same thing & (I do have an attic fan so in the morning I get the house as cool as possible with that) before I leave I close the house up & kick the air on but not as low as I normally would because:

a. I don't want in runing all day, just don't want to miserable when I walk in the door

b. in this type of weather, you're mostly needing to knock the humidity

c. then when you get home you can knock it down another degree or two if it isn't satisfactory

A programmable thermostat is nice if you know how to install one...I had one, but it burned up & I don't have anyone to install a new one & having one installed I don't feel is cost effective.

My vote is to think about what you are truly debating about- this probably will only be a problem for a week or two, is it really worth that much emotional energy? that being said, I would close the house up when we left- close all of the curtains to keep the sun out and most likely when you get home, it won't be that hot in the house(depending on your insulation). If it is too hot- you grab an ice water and tell the hubs you are going out to dinner- afterall you are 8 mos pregnant, and dinner dates are about to become a real treat(if this is your first).

My husband worked for a basketball arena before we moved here. We had the HVAC specialist come over because our bill was so high we thought something was broken. He told us the best thing to do was to keep it cool. Shut the windows before the house starts to warm up, then it won't get as warm (if the air is on) and you won't need as much to keep it constant. I completely understand though, I would love just to suck it up, but being 7.5 months pregnant I can't handle coming home to a house that's 80°.

I would turn the A/C on a higher setting during the day (maybe 78) so it doesn't have to work too hard when you do turn in back on.

get a programmable thermostat you can set it for different temps at different parts of the day or have it come on an hour or so before you get home

I always leave the A/C on until it doesn't need to be for the rest of the year. It is on all summer. It not only keeps the house at a constant temperature (I don't have the programmable thermostat), but it keeps the humidity low. With the humidity the way it has been around here lately with all the on-again off-again rain and storms, the humidity has been around 60%-100%. That's a lot of water for an air conditioner to try to pull out of the air.

Honestly...neither. I would close all of the windows before you leave and then guage the atmosphere when you get home, then decide if its worth it to turn the air on, or if you should just open the windows back up.

Do it in the morning so your AC doesn't have to work so hard to cool down your home. I also close al blinds/curtains that don't have a houseplant sitting in front of them. Hope you win the "dabate." It will be much easier on your all's bank acount if you do. Good luck!