Is it cheaper to keep your A/C on all the time or turn on and off?

[lisaross]

OK, i just sent my programmable thermostat - i have it go to 77 at 10:30pm for sleeping - i like it cool so w/fans going it might be ok or i'll change it to 76! As for the am when we get up i set it to 78 and when we are gone i have it at 80 during the week and 79 on the weekends! I donnot like to feel "cold" in the summertime inside so i think this should work for us!

Today, its going to be in the 90's and for the next few days - last night was still cool outside so i had my windowns open, but this morning i closed them so that i could keep the cool air in and the humidity out - i also closed some of the bedroom blinds to keep the sun out - its nice and cool in my house now - its 75 and the a/c did not even click on yet!

lisa

 

[estherhead]

Here is a quote from Energy Star, which is the company that rates air conditioner's. They are the last word on A/C efficiency.


How much should I put back my heat or air conditioning while I’m gone during the day?

Answer
There are no hard-and-fast rules - - your set-backs largely depend on your own comfort, your home’s insulation, the type of heating and cooling system you have, and the climate. On average, for every degree you set back your thermostat, you can save 3% on your energy bill. Through proper use of a programmable thermostat (using the 4 pre-programmed settings) you can save about $150* every year in energy costs for a typical, single-family home.

*The $150 savings assumes an 8 hour daytime setback and a 10 hour nighttime setback of 8 degrees F in winter and 4 degrees F in summer.

And here is the link to the room air conditioner question:
http://energystar.custhelp.com/cgi-...p_faqid=3155&p_created=1184002639&p_topview=1

Honestly, I think it summarizes what both the other HVAC tech (yes, I have my universal HVAC lisence) and I were saying, as well as cruisinfamily's post. For best efficiency, buy a programmable t'stat, set it for 5 degrees or so higher when you aren't home, and have it come back to temp about an hour before you come home.

 

[binny]

I have a raised ranch and the second level really holds the heat. Last summer we put some thermal curtains on the upstairs windows and sliding glass door. We closed them when we were gone for the day and it made a huge difference. It also helped with the heating in winter. New energy saving windows will also make a huge difference.

We did this too this year it also helped at night in the winter keeping the cold air out.


I also looked into a company that tints windows, they say that can stop a lot of heat coming in as well. Does anyone know anything about that? They can do our South facing windows for about $250. Wise investment?

 

[jeankeri]

I have a new portable AC that has a DRY setting- dehumidifier that vents out the hot air. If I leave it on the dry setting while out, will the unit have to overwork itself when I set it on cool when I return? Or should I set it to dry only if the outside temp reaches a certain temp. 85 maybe??

 

[aprilvaca04]

We have window units , so they should be turned off during the day? Dsil insists they need to be on !! Experts pleas help!!

I am anxiously awaiting an answer to this also

 

[estherhead]

I am anxiously awaiting an answer to this also

Sorry all, I put the link to this in my above post. Here is the info from that site (Energy Star)

"There are a lot of variables in this question. You will always save money if you turn your air conditioner off or put it on a higher temperature setting while you're not in the room. However, with many Room ACs, unlike central air conditioning, you can't program it to go on at a certain time, so when you come home you will have to set it to the desired temperature and depending on the unit, the outside temperature, and your insulation, it will take a certain amount of time to reach that desired temperature. Another option is to use a programmable wall outlet timer with your room AC. Make sure that the amperage and voltage ratings of the wall outlet timer are appropriate for the electricity demands of the room air conditioner.

If you have a separate Room AC in your bedroom, it might work to turn that off while you are out, and turn it back on when you return and by the time you're ready to retire to your bedroom it will be cooled off.

If you are purchasing a new room air conditioner, you may want to look for one with a built-in timer and/or programmable thermostat settings.

For more tips on how to stay cool this summer, visit: energystar.gov/home."

 

[polineedyan]

I used to have an apartment in a high rise. I would leave the air on (or at a low temp setting) all day. Then, when I got home in the early eve/late afternoon, of course the apt was cool. And since it was cooler outside, I didnt need to run it at all at night. So there ya go. No, you dont need to run it constantly. But, if you keep it cool when its hot out, then the house will be cool in the evening, and you can probably even leave it off thruout the night. Youll be running it the same amount as you do now, just during the day instead of at night..

 

[disneychrista]

All i know is when i have my a/c running it costs me more. If I turn it on for n hour when I get home to cool the house off, my bill is less. I am fruggle and refuse to pay more than needed. My house is usually around 78 - 80 in the summer. I use fans and let natures a/c cool off the house at night. I use box fans in the window to pull in the cool air and then to keep that air circulating so the house stays cool. I only have to turn the a/c on when it get to the upper 90's - 100's.

 

[go2cindys]

In my new condo on the 3rd floor, I leave my ac at about 80 and it's great even though I nearly melt in my daughter's home when hers is set at 75.

When it comes to going away for a few days or 2 weeks, I usually turn it off (and yes it's warm when I get back). We have bad thunder and lightning storms here in MD and I was told that an interruption in electricity is really hard on the AC unit. We had one distroyed several years ago in my other house because of an electrical storm. We had to replace the transformer (I think that was what it is called).

If I go away during the colder months, I just lower the thermostat 10 degrees. It doesn't take long to warm up.

 

[Kickapoo Joie Juice]

I posted on some other thread about this before.

We tried it each way for a month:

First bill 386 with it set to 76 all day (3100 sq ft house)

Second bill 181 with it set to 82 while we were gone from 10-4.

My guess is that it's the power company that's telling you to keep your house cool for your chairs and tv's....

 

[britfish]

for yall you HVAC experts, what is the best way to set your temp. on the thermostat in the winter. We have a programmable thermo and set it at 55 during the day (when we are out) and 65 when we are home. Maybe it would be better to leave it at a constant temp. w/ oil prices so high.

 

[drakethib]

I posted on some other thread about this before.

We tried it each way for a month:

First bill 386 with it set to 76 all day (3100 sq ft house)

Second bill 181 with it set to 82 while we were gone from 10-4.

My guess is that it's the power company that's telling you to keep your house cool for your chairs and tv's....

I think this reinforces what the HVAC folks are saying. Set it up 5-6 degree while you are gone and your a/c wont have to work as hard when you want to cool off.

BTW, I keep my A/C on about 70.

I am all about saving money but I do draw the line at somethings, I cant sleep worth a darn when it is hot.


I think everyone needs to try to see what works best for themselves much like you did.

Don't forget to change your air filters.

 

[jultomzach]

My husband has been an licensed HVAC mechanic for 28 years and he supports what every other HVAC expert on this board has said so far...Do not turn it way down when you are away. His other pet peeve, those that turn their unit to 60 degrees in 100 degree heat because they believe it will cool the space quicker. But gotta love those that turn their units way up and down because they keep food on my table!!
Actually, I think there are two separate answers to the OP question of "Is it cheaper?". While it may take less electricity to turn your unit off or down by several degrees when you are not in your home, it is much more taxing to your ac unit. So while you may save $$$ on your electric bill, you will need to consider your unit maintenance, repair or even replacement costs. The age of your unit also greatly influences it's efficiency. Because my husband can replace our unit and because he gets materials at cost, we will probably replace our unit next year. Even though it is only 9 years old, the newer ones are much more efficient (and my parents are in need of a unit so they will get ours).

 

[Kickapoo Joie Juice]

My husband has been an licensed HVAC mechanic for 28 years and he supports what every other HVAC expert on this board has said so far...Do not turn it way down when you are away. His other pet peeve, those that turn their unit to 60 degrees in 100 degree heat because they believe it will cool the space quicker. But gotta love those that turn their units way up and down because they keep food on my table!!
Actually, I think there are two separate answers to the OP question of "Is it cheaper?". While it may take less electricity to turn your unit off or down by several degrees when you are not in your home, it is much more taxing to your ac unit. So while you may save $$$ on your electric bill, you will need to consider your unit maintenance, repair or even replacement costs. The age of your unit also greatly influences it's efficiency. Because my husband can replace our unit and because he gets materials at cost, we will probably replace our unit next year. Even though it is only 9 years old, the newer ones are much more efficient (and my parents are in need of a unit so they will get ours).

Can I have your old one? The 40 yo secondary hvac in our house is broken-9 yo is like, brand new for me!

 

[BelleBeautyandtheBeast]

The big problem with this question is - there are too many variables.

Each house is unique, each person's needs are unique, every air conditioning unit is different and every area experiences different weather.

You need to do what works for you.

 

[Whitaker24]

Last week our AC would run all day an night with out cooling the house the temp inside would get to 81 and only go up to that point, called service guy he added 2 lbs of freon and cleaned the coils and its been good to go since

i have a programmable termostat too works great in the winter when u are using he so it wont run that gas bill up during the day, i think for use as some have said works best if i leave the air set on 75 during the day and then just kick it down to 73 when i get home about 30 min before wife an lil boy, so i wont be using the program in ac mode.