Edwin Pawlowski wrote:

"Rich" wrote in message

I could never understand this, when you close off unused rooms aren't you
lessening the load on the system over all? In heating and
air-conditioning? Or is it worse for one verses the other??

Thanks, Rich


Yes, you are, but the systems are designed to run at a certain capacity. If
the capacity is not used, they will cycle more frequently. Is that bad?
Depends. Compressors are often rated at X starts per hour.

You have to understand about load on the system. With few exceptions of
some variable machines, the heater or AC compressor is either off, or it is
on. The thermostat is a switch that turns it off or turns it on. There are
those people that when chilly will turn the thermostat up higher thinking it
will heat faster. No, it won't. When you turn on a light in a room, it is
on. Pushing the switch harder does not make it brighter. Same with a
heating and cooling systems. Burner on is putting out full capacity.

Not as a general rule, since many systems are staged.


Shutting down dampers will change the air flow and static pressure on the
blower. If it has a lot of resistance, it can actually work harder trying
to overcome the blocked vents as it would just blowing and circulating the
air.

Doesn't work that way. The blower will unload with greater static.

Just like blowing through a straw, bigger is easier.

Lower resistance with a constant applied force means more work, not less.

hvacrmedic