"AUTO" HVAC A/C in the winter??? (1 Viewer)

[chrisbruck]

Dumb question and maybe a moot point... Anyone have a preference on running the HVAC in the colder winter months in AUTO mode with the A/C "on"?

I know running it,
A). keeps things lubed in the system
B). dehumidifies to some extent with a car full of steamy people
C). burns more gas

Just curious what other do in the winter...

 

[Bomar]

Mine stays on for all the seasons.

It has no bearing on my MPGs and that is because I measure it in smiles per gallon.

 

[ClassyJalopy]

Yes - My windows fog a lot less when I have the A/C compressor turned on in winter. Since A/C is on all 12 months, I can't tell you if it has any impact on the fuel consumption.

 

[2001LC]

Measured in smiles per gallon. I like that!

There is two effects when using HVAC and AC, to MPG. Fan blower motor and AC compressor, belt drag when engaged. Both use some HP, due to increased resistance on crank shaft via drive belt. (AKA serpentine belt, aka fan belt). Any electrical use taxes alternator, which transfer load to belt. AC Compressor is simple to understand, it's machinal drag.

I did extended real word testing over 13 years and ~120K miles. The result are in one of MPG threads, in mud somewhere. What has more of a bearing on MPG, is lead foot and adding weight.

A trick to reducing or eliminating AC use in winter. Switch air from circulating to outside fresh air. This will eliminate flogging, in most cases. So no need for AC to defog, which AC can then be manually turned off then.

If only a cold day, not sub zero. Turn heat to full hot, set to fresh outside air, turn off cabin HVAC blower fan. Fresh air from outside, will pass the heater cores on its way into the cabin. Seat heater are nice at this point. They do draw electrical power, but less than blower fan.

When AC is turned on, do leave on a few minutes. This is to circulate oil in AC compressor. Rule of thumb 2 minutes.

Those that run front and rear AC often. Should mitigate rust areas, induce by condensations from AC. At front AC drain on stabilizer bracket on frame and rear RH quarter tip inside body panel cavity.

RH frt stabilizer frame bracket. AC condensation hose comes out RH fire wall and drips on bracket. A mud member sells a kit, to diver hose.

RH rear body cavity, below rear AC unit.

Condensation is hidden in cavity, sweats of rear AC unit. Working it way out. There are weep holes, but dust clogged them in time.

Cleaning cavity is an important first step. On both side even if AC not used much.

3M body wax, is one product. That can be used after cleaning.