I have a programmable thermostat and have it programmed to lower the temperature to 21 at 3pm. I then have go to to 22 at 10pm. During this time the AC in the house is constantly running. Is thier something I can do to automatically have the AC go on and off like the furnace does in the Winter?:confused:

21 and 22 degree's is awefully cold.

My air conditioner would run all the time trying to get to that temperature. Try setting your thermostate to 26 before you get home and 32 during the day when your not home.

I couldn't imagine setting a temperature so cold that I would have to bundle up just to walk around the house. Do you sleep with your winter duvet at night?

Your furnace should shut off automatically once the temperature hits the programmed setting. If it's not, you may have a faulty thermostat.

(We have our thermostat set to 26 when we're away, 25 when we're at home and 24 overnight.)

In my opinion, 21/22C is too low a setting and is probably the reason why the AC is always on. The AC might also be sized too small (btu/hp wise) for the area it is supposed to be cooling.

I have my programmable thermostat set to 24.5C from 10PM - 6AM, 27C from 6AM - 3PM, 25.5C from 3PM up to 10PM and this works out fine for me and the family. The AC usually turns off between 7 to 8 PM, doesn't turn on until 10 PM then turns off again at around 2 AM. This is based on the past couple of days when it was quite hot and humid here in Ontario.

That is pretty cold.... what temperature does the house acutally get to? Sounds like it is never reaching it... but is it close or is more than 3 or 4 degrees off.

I can share an experience I had with our previous house.

I had problems with heating and cooling that house and it was a only 3 yrs old when we lived in it.

To summarize I did the following...
1) Made sure the furnace filter was always replaced with a clean filter regularly... expecially in the heavy heating and cooling periods of the year.
2) turn off the humidifier in the cooling months and close/shut the air bypass for the humidifier.
3) The basement was unfinished.... we had a ton of air leaks from all the ductwork... I taped all the seams and joints anywhere I could feel an air leak. Made a huge difference.
4) adjusted the heating registers for the seasons we were to get.
5) Shaded the A/C unit with shrubs... the a/c unit was on the southern exposure of the house and in direct sunlight all the time until the shrubs went in.

All of the above made a huge difference and actually evened out the comfort of the whole house.

Thanks for the replies guys. My wife is wanting the house like an icebox and we have had "discussions" about it. I usually hang out in the basement (as it is much cooler) but she likes to have the house cold and complains if its at 24.:eek::rolleyes:

If this is your first year in the house, you'll get a frightening electricity bill or two or three if your A/C is on that much - especially if we have a hot summer.

If she wants it cold, I would do what the others suggest and check for air leaks etc and then bump it up .5 degrees as a compromise for now. When you get your first bill, it might be too late to do anything because you'll probably already be a full month or 6 weeks into the next cycle.

Close all your windows and blinds during the day, especially if the sun is out. If your insulation is tight, you will save a lot of money. If you do not have blinds or curtains on all of your windows, installing them could pay back in reduced electricity costs in a month or less.

That is pretty cold.... what temperature does the house acutally get to? Sounds like it is never reaching it... but is it close or is more than 3 or 4 degrees off.

I can share an experience I had with our previous house.

I had problems with heating and cooling that house and it was a only 3 yrs old when we lived in it.

To summarize I did the following...
1) Made sure the furnace filter was always replaced with a clean filter regularly... expecially in the heavy heating and cooling periods of the year.
2) turn off the humidifier in the cooling months and close/shut the air bypass for the humidifier.
3) The basement was unfinished.... we had a ton of air leaks from all the ductwork... I taped all the seams and joints anywhere I could feel an air leak. Made a huge difference.
4) adjusted the heating registers for the seasons we were to get.
5) Shaded the A/C unit with shrubs... the a/c unit was on the southern exposure of the house and in direct sunlight all the time until the shrubs went in.

All of the above made a huge difference and actually evened out the comfort of the whole house.
1) I replace the filter every 2 months with a washed one. (I have the fibre ones you can wash and re-use)
2) I do exactly that
3) When we finished the basement we first tape/sealed all air leaks
4) I have blocked off the vents in the basement (as it doesn't need the cold air) except for one so that the furnace doesn't explode. :)
5) Not sure if you mean the AC fan out side but I'm not sure how shading it will keep it from comming on when the temperature sensing thermostat is inside the house.

Thanks for the tips.

5) Not sure if you mean the AC fan out side but I'm not sure how shading it will keep it from comming on when the temperature sensing thermostat is inside the house.

Your A/C unit outside has to dissipate the heat from inside the house. If the sun is shining on it, then it will heat up and be less efficient than if it was cooler and out of the sun. But try not to restrict the airflow.

I try to have the temperature between 70F-72F so 21C-22C seems normal to me.

I try to have the temperature between 70F-72F so 21C-22C seems normal to me.

I agree but I grew up in Northern Ontario and am one of these idiots who actually loves winter.:)
(also good point about closing the humidifier bypass. Forgot to do that this year. Thanks)

Last year was our first summer in the new house and once we got the A/C installed it didn't feel comfortable until the inside temp hit 21/22 C.

I've since invested in a nice de-humidifier for the basement that seems to be pulling about 70-75 pints / 24 hour period. This has made a HUGE difference in the rest of the house, it's now very cool feeling at 24/25 C.

My only hope is the new de-humidifier is using less electricity than the 13 SEER A/C unit. :)

While I find that 21-22 is on the low side, I similarly find the suggestions about 24-27 on the high side. To each his own.

1. Are you sure it's your A/C that is on all the time or just the fan? Having the fan on all the time is not a bad thing, actually.

2. There are two things that the A/C does -- cools the aird and dries it out. Dry air makes it a heck of a lot easier to take higher temperatures, so check the humidity level in the house and if it's too high, do something to lower it. A good rule-of-thumb value is 30-50% RH (Relative Humidity).

3. Someone suggested turning off the humidifier in the heating months? Was that a typo? You want to humidify the air when the furnace is on. However if it gets below a certain temperature then you can turn down so that the RH is 30 or lower.

4. I've gone about some unused rooms and closets closing the vents and making sure the doors are closed as well. Not sure if this makes a huge difference, but assuming the vents/doors actually work you are, essentially, cooling a smaller volume of air. In theory, at least.

5. Show your wife next month's electricity bill, then suggest that a portable oscilating fan might do wonders for her.

6. Install ceiling fans in bedrooms.

7. All the other advice already given.

wprager has mentioned it, but I'll second that putting fans on (ceiling or other) will allow you to keep the temperature a little higher but still feel cool.

My AC is designed so that it can barely keep up on the hottest day (most efficient design). The past few days were quite hot and very humid. I have the thermostat set to 26 for the day and let it cool to 23 starting at 11PM (passing through 25 and 24 settings at 4PM and 8PM. This past few days the AC came on in the early afternoon and didn't go off until about 3-4AM, when 23C was finally reached. The house then warmed up to 26 by the next afternoon and the process was repeated for these very warm days. With more typical outside temperatures and humidity, the AC would cycle after reaching the setpoint temperature, but that may also take a few hours if going from say 26 to 24.

Also, if the AC is overdesigned (too large), it can cool a home faster, however, an overdesigned AC system will not run enough to dehumidify, so the more your AC runs, the better it is from a dehumidifying standpoint, which also makes 23 or 24C seem plenty cool enough.

The reason some people need to set to 21C is because the AC is not dehumidifying enough and the Humidex in the house is still 28-30 due to high humidity. 23-24 with a 24 Humidex is more comfortable, better for you and more energy efficient.

So, if your AC can cool a house from 26 to 24 in an hour or two during very hot/humid weather, it's way overdesigned and won't have enough time to do the dehumidifying required.

Another thing that helps is to block the appropriate cold air return register depending on the season. If your cold air returns are in pairs with one near the floor and one near the ceiling, block the floor one in summer so that you draw warmer air from near the ceiling, then swap that when you switch to heating mode.

I bought a big sheet of plain white fridge-magnet style material and cut that to fit. Before that I just held a sheet of 8½x11" paper over each cold air return with a couple of fridge magnets.

Was a busy day today, but i actually had a call similar to the OP. Customer was saying it runs all day..

Here is the thing. We all have our own personal comfort zones. So while its fairly easy to agree on a range of "Obtainable" heating temperatures, coolings is a whole other beast. The variables are so much greater.... the biggest factor is humidity and the fact that cooling takes alot more time and energy then heating...

Today i walked into a house set at 20C and the customer was complaining it was running all day long for the past few days... I reminded him that it had hit the 30-34C and humidity was very high. And if he insisted on that low a temperature that he should expect the unit to run very long long hours. The house was dry and comforable but i thought i saw David Suzuki walk in the temperature hit 18C while i was doing my call.... David was not please! LOL

To each his own. For various reasons people request certain temperatures. But when we are asking for a 12-14C drop in temperature from the outdoor ambient expect to have the unit run and run long.

My only tips i can give as a service tech are the following:
-when we are in a heat wave, dont open windows in the evening because things have cooled off out doors... Your letting all the humidty that you spent all day removing...
-close the humidifier by pass valve.
-Pick a reasonable temperature. 18-20C i just dont find reasonable. 22-24 is more realistic but again to each his own. just expect the unit to run long if you ask for low temps. (so many of my calls are for this)
-Resist using the set back temperature settings on your stat. IF you must setback try not to go more then 2-3 degrees. The longer you have the unit off the more the humidity rises and the internal temp... If you like 22C dont setback to 28C all day... Again personal prefs.
-Run the fan 24/7 it helps eliminate the "stacking" effect you get where all levels of the home are at different temps. Continue mixing the air around between cycles helps keep an even temp
-DONT BLOCK ANY RETURN AIR DUCTS! Starve the A-COIL and you could freeze the unit. IF you must block anything the basement supply vents can be closed. Mine are closed as our TV is in the basement and thats where we chill all nite :)
-avoild dust blocker type filters in the summer. The 3M filters are in some case too restrictive as are some of those permanent filters.... Keep the change or cleaned regularly. I typically suggest a cheap fiberglass filter for the summer and use the 3m's and others for winter... Assumer temperture rise can stay within spec.
-keep the condenser clear of grass and pollens... spray it off with hose if needed.


Keep cool!

Last year was our first summer in the new house and once we got the A/C installed it didn't feel comfortable until the inside temp hit 21/22 C.

I've since invested in a nice de-humidifier for the basement that seems to be pulling about 70-75 pints / 24 hour period. This has made a HUGE difference in the rest of the house, it's now very cool feeling at 24/25 C.

My only hope is the new de-humidifier is using less electricity than the 13 SEER A/C unit. :)
A lot of the moisture being removed the first year or so is due to the house "drying out". There's a lot of moisture in the lumber, etc that takes time to be drawn out and "adjust" to your home's "climate". Shouldn't be as noticeable this year.

Is thier something I can do to automatically have the AC go on and off like the furnace does in the Winter?
Quite simply, don't turn the temperature down so low. A programmable thermostat that has more than 4 daily settings can help by allowing smaller increments in temperature changes. Late afternoon, early evening are the most inefficient times to run A/C and the most difficult times to cool a house, especially if the A/C has been off all day. Expect the A/C to run continuously if trying to cool the house at those times. Typical comfort zones are, 26c-28c (78F-82F) when not home for several hours, 23c-25c (74F-77F) while home, 21c-23c (70F-74F) at night. I set the A/C to 78F when away, 76F when home and 72F at night. There are days when it feels more comfortable outside than inside. That's usually a cue to shut off the A/C and open the windows, unless it is very humid and temperatures are expected to rise.