J Jensen wrote:
"Joseph Meehan" wrote in message
...
J Jensen wrote:

1. Keeping the a/c cooling the house all day uses less electricity
than turning it off and then back on in the evening or when you
return from a vacation.

Maybe, it really depends on many many factors. It would be best
to measure the specific application.


It seems to me that it would clearly be best to let it get hot in the
house if no one is there during the day and just run the a/c hard to
cool
it down in the early evening. The only issue is that the a/c is then
doing
a lot of work when the outside temperature is still near its hottest.
I
am told by someone that this caused the unit to run and run for hours
continuously, but my suspicion is that that was due to a lack of
freon or
some other malfunction (it was a small house!).


[snip]

6. If you have high ceilings and ceiling fans, it is more energy
efficient to leave the fans running at low speed all the time to
pull down hot air and get it to circulate through the a/c system.

Only if it is you goal to cool the ceiling.


I am glad that everyone seems to agree that running all the fans and
cooling
all the air in the house is a bad idea, but, believe it or not, it was
proposed by a home efficiency expert to came out to the house several
years
ago. (I wasn't home at the time so I didn't question him on why he
said that).

--JEff

If designed properly, an AC system WILL run continuously on the hottest
(outdoor design temperature) days in order to maintain the desired
indoor (design temperature). Obviously, if the home has heated up
beyond the indoor design temperature then it will take the system a
while to cool it back down.