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(J Jensen) wrote in message . com...
In regards to the recent posting I saw about running the a/c or opening the
windows, I would like to list several statements that people have made to
me about air conditioning. The location is Texas, where the temperature
is about 75 F at night and 100 F at the hottest part of the day.

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.

Part of the answer this has to do with where in Texas you live. If you
live in the Houston area, you would probably want to leave it on at
all times, if nothing else to prevent a build up of humidity in your
home. If you live in a less humid part of the state, this is not as
much of a consideration.

2. Running the a/c a few degrees colder at night cools the big cement slab
that the house is built on, and thus saves electricity during the day
(the a/c is set back to normal living temperature during the day).

Realistically, you have little hope of cooling down a large cement
slab, except if you maintain a constant temperature in your home.

2b. If the temperature inside the house reaches 78 F at 10 AM on both days
with the a/c set colder the previous night, and also when it was just
set normally the previous night, then that proves setting it colder made
no difference.

It anything, this simply reveals you need a larger air conditioner
unit since your current one is unable to maintain the temperature
within acceptable tollerances.

3. The a/c uses less current at night ( you measure it with an ammeter as
it is running ).

I personally have not found this to be the case, either in upstate New
York or here in New England. The current drawn by the compressor in an
air conditioner barely reflect changes in temperature conditions.

4. The a/c uses less current if you spray the outside unit with the garden
hose and then measure it with the ammeter.

I'd assume that you are joking here.

5. Shading the outside unit (compressor and condenser) does not reduce
electricity costs [Assume shade does not block air flow].

Shading the condensor unit will improve air conditining performance,
but will have only small impact on electricity costs.

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.

This depend on how interested you are in air conditioning your
ceilings. Most people couldn't give a hoot.

7. It isn't worthwhile to check on the amount of Freon (or whatever) that is
in the system -- all that matters is measuring the temperature of the
cold air coming out (say 62 F) and the outside temperature or maybe the
attic temperature.

If the temperature differential between the intake air and the outlet
air temperature are operating within specificationd, there is no need
to measure the freon pressures.

Harry C.