Harlan Messinger wrote:
My house is on three floors, it has central air conditioning, the
thermostat is on the middle level, and there's an exhaust fan on its
own thermostat in the attic. When the temperature is comfortable on
the middle floor, it's too warm on the top level. It's a bit cooler
on the ground floor.

What's the most effective, assuming any of them is effective, of the
following approaches?

1. Partly close the incoming air vents on the middle floor and
possibly the ground floor. The theory: a relatively larger portion of
cooled air will go to the top floor.

2. Hang a ceiling fan in the stairway between the second and third
floors to push the air upwards.

3. Hang a ceiling fan in the stairway between the second and third
floors to push the air downwards.

The most effective way is to have three systems or zones. It also may
be rather expensive. I plan on going that route when I replace my system.

The problem with #1 is it may cause problems and even damage your system
with too high resistance.

I would say #2 & #3 is not likely to work, but if the room arrangements
are just right it may. Keep in mind that if it does push cooler air up it
also means that the air pressure will be a little higher up there keeping at
lest some of the cooler air from the A/C from getting up there through the
existing ducts. It might make more sense to push the warmer air down to the
lowest floor.

My suggestion for something that would work, would be to have a
professional HVAC do the manuals (maybe just the "D" in this case.

--
Joseph Meehan

Dia duit