CBHVAC wrote:

"CJT" wrote in message
...

m Ransley wrote:


Stormin, so cold air is heavier , does my car take more HP to run in
cold air from wind resistance.


It probably does, if that's all you consider. Happily, engines are more
efficient when their intake is cold (plus, you're less likely to be
running the A/C).



On modern vehicles, when you go to WOT, the AC is kicked out...even then, at
highway speeds, less than 2HP is used to run it.

The reason that a car likes cold air is that cold air is more dense. Helps
to slightly increase volumetric efficiency.

The reason that with HVAC issues you have a faster speed on cool than you do
low, is two fold, and if Stormy had a clue, (he does not) he would know why.

There is no *requirement* that heating speed be lower than cooling
speed. What is important is that you have the proper cfm per ton set up
for cooling, and that your temp rise in heating falls within the specs
(temp drop range) listed on the data plate or label in/on the furnace.
Factory default isn't necessarily what's going to be required.

hvacrmedic