What is the most economical method of running house central air system

Question

Is it more efficient to leave the central air running at a set temperature or use a programmable thermostat and have the temperature change during the day.

Would it save my hydro bill if I left the fan running constantly to circulate the cooled air.

Answer 1

A programmable t-stat saves money by letting you increase the temp when not at home, this can save big bucks! Next letting the inside fan run all the time uses more energy if the duct work is in the attic you will be pulling heat into the home when the compressor cycles off. It is cost less money to cool down a house say 5-6 pm when the sun is not as hot.

Answer 2

The conservationists will tell you that you should get a programmable thermostat which will allow you to raise the temp after you leave for work and have it a comfortable temp when you arrive back home.  All that doesn't matter if there is someone home all day.  Air conditioning techs, on the other hand, have told me to set the temperature and leave it alone.  That is what I have done for years.  If you live in a hot climate, as I do in Texas, it takes a lot of energy to cool the house and all the contents back down after the temperature has been allowed to rise during the day.  There's no need to leave the fan set on anything but Auto.  The a/c fan, and ceiling fans for that matter, only circulate air.

Answer 3

The sole determining factor (for the same house and insulation) of expense is determined by the temperature difference between the outside and the inside for each minute of each day.  So, if no one is home, turn the system off.  At night, set it as high as you possibly can and still be able to sleep.  It won't help much, if any at all, to leave the blower on.  If you MUST have the temperature lower when you walk in the house, use a programmable thermostat.  One of the problems with them is that if your schedule changes, it is very easy to leave it set as is.  

Answer 4

why not leave all your windows open

Answer 5

Set it and forget it.

Answer 6

Set it for the day and night and let it go,,, also do let the fan run...