I have central air in a 1650 sq ft. 2 story house. It is an old house (1930) and as such there are no returns on the 2nd story so while I know the system isn't 100% efficent, how long should it take to cool the house down to 75 degrees from 80 (outside temp. of 85).
I'm new to the house and have only turned the A/C on so far twice this summer-and each time it has taken like 2-3 hours, if not a little more, to get the house to cool down 4-5 degrees. My dad says this is fairly normal when starting A/C for the first time in awhile because you have to get rid of all the hot, stale air and after the initial long period it will balance itself out, but I just want to be sure! Is my dad right? How long should it take?
No 100% eff. units have every been made. You have to remember that you'll only be getting about a 15 degree drop accross the evap. coil. Make sure your blower wheel is clean, filter is clean, evaporator clean, refrigerant charge dead on the manufacturers spec, condenser coil clean. Then if your house is insulated well you'll get a pretty good response from your a/c.
Call an a/c service and get it checked out. You may be able to find someone to do a thermal scan too.
2 to 3 hours is not bad to get the temp to drop at least 5 degrees. The best thing to do, is to set it for increments then when you get it comfortable to like it (ie 78 degrees), leave it there. It has been around 95 outside all day, and at 78-80 degrees, our house has been comfortable without being too cold. Of course, this is with only two 5,000 btu window units running, and a room fan circulating the air in the living area, and ceiling fans in the bedrooms.