We have a 1 story 2000 sq. ft. ranch-style house in Dallas with a 3 ton A/C that I beleive is about 12 years old. I would appreciate your advice on the best setpoints for the programmable thermostat to minimize energy usage. Specifically, whether to turn the A/C completely during the day when we are both at work.
I have searched the forum but found conflicting advice and I think part of this may be due to homes in different climates (e.g. we are not as humid as Houston nor do we get much a break in the temperature at night as northern cities). For example, the high during the afternoon is usually around 98-100, and it may stay above 90 degrees until well after midnight. Even at 3am it may not get below 87.
Here is my t-stat program currently:
7:30AM - we leave house, A/C is set to 88 (highest it will go).
6:00PM - A/C to 82. We usually arrive home between 6:30-7:30 and if the A/C has been off all day, the temp will be 86-87. If the A/C comes on at 6 then it will be a few degrees cooler when we walk in the door.
8:30PM - A/C to 77. The house will then take until 11PM to reach this temperature, and will start cycling after midnight (it's still 90 outside). It will stay set at 77 until we leave at 7:30AM the next morning.
On the weekends when we are usually home, I set it to 82 during the day and 77 at night. So we are ok with the comfort level at 82 right now. So am I making a mistake by setting the t-stat so high while we are at work? I don't mind coming home to a warm house, my main focus is on cutting our outrageous electricity bill.