Uncle Monster wrote:
On Friday, July 17, 2015 at 9:10:40 AM UTC-5, Bob F wrote:
songbird wrote:
i see in the other thread that there is talk of
running the AC to get rid of humidity, so i thought
i'd bust this topic out into it's own thread...

is there any significant difference in cost between
running a dehumidifier and the AC?

my guess is that in our case that the cost would
be different, but the tradeoff against having another
machine to maintain or purchase might make it not
worth the bother for as little as we use it.

the cost would be different because when we run the
AC two motors are running whereas if we had a separate
dehumidifier only one would be running (and it might
be a lot more efficient).


Same # or motors either way. One compressor motor, and one fan motor
for "portable units". AC built into the house heating system would
have an extra fan motor outside. The AC generally would draw
significantly more power when running than a portable dehumidifier
because they generally involve larger compressors. A dehumidifier
will heat up the area it dehumidifies, whereas an AC will cool it
because the AC releases the heat it produces outside. If hot humid
weather is the issue, the AC will likely get you more comfort for
the energy used but will use more energy if used much.

An AC unit doesn't produce heat, it moves it. Any heat produced by
the motors is small compared to the amount of heat transferred from
the inside to the outside. A heat pump moves heat in either direction
thus the name heat pump. 8-)

Try running a dehumidifier continuously in an enclosed area. You'll quickly
notice how much warmer that area becomes. There is a lot of waste heat produced
by the motors in AC or dehumidifier. The AC just hides it by exhausting it
outside.