"Mike S." wrote in message
ups.com...
I have central air in my house and the unit and everything is about 20
y/o. I realize it should be updated but I have no control over that.

The problem I have is that if I set the thermostat to to 70 degrees
fahrenheit, then the downstairs stays about 70. But the upstairs will
be anywhere from 76-80, depending on the room and how hot it is
outside. So the problem is that people complain that it's too cold
downstairs and too hot upstairs. Ideally, I would like it to be about
76-78 downstairs and about 74 upstairs.

Why does this happen and is it normal? I know that a lot of air blows
out in the vents downstairs and not a lot blows out upstairs. I shut
off all the vents that aren't needed and close the doors to rooms that
aren't used. I have the fan set to "auto". I don't know if leaving it
on auto is better than setting it to "on". I don't like to mess with
it because it seems to cause problems with it.

Any opinions or suggestions (other than buy a new unit)?

Lots of good advice in other posts. You should be aware that "buy a new
unit" will not solve your problem of unbalance between the heat loads and
the air delivery between the two floors unless the airflow is changed. A two
zone system or two separate systems would probably be much more
satisfactory.

You may have the best low cost results with insulation, awnings or other
shading, storm windows, caulking, or other means of reducing the heat gain
in the upstairs.

Don Young