A/C button when heating?
Thread Starter
Junior Member
Joined: May 2012
Posts: 42
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GLK 350 2010
A/C button when heating?
GLK 2010. I was driving in cold weather and decided to turn the heater on. I can set the temperature on maximum and I can almost immediately feel like hot air is going out from the air vents. Everything is fine at this point.
Now I see there is also A/C button which is deactivated. So what difference will I notice if I press it?
It perfectly makes sense when I want to cool down the interior - I press AC button and cold air goes from the vents. But what difference do I get when I want to heat up the interior?
Now I see there is also A/C button which is deactivated. So what difference will I notice if I press it?
It perfectly makes sense when I want to cool down the interior - I press AC button and cold air goes from the vents. But what difference do I get when I want to heat up the interior?
Super Member
Joined: Sep 2009
Posts: 527
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From: Old Dominion
2015 VW GTI.S4; 2016 Audi Q3 Prestige
you are dehumidifying when you have A/C on & the heater.
A/C on @ any time will dehumidify.
Example is that your window fogs up during a winter rain/snow because of condensation due to humidity. Yet you want to be warm too. Turning the heat & activating the A/C will solve both the condensation (fogging) & keep you toasty.
A/C on @ any time will dehumidify.
Example is that your window fogs up during a winter rain/snow because of condensation due to humidity. Yet you want to be warm too. Turning the heat & activating the A/C will solve both the condensation (fogging) & keep you toasty.
Super Member
Joined: Aug 2011
Posts: 861
Likes: 38
From: Philly area
350 GLK, C280
Many people turn the AC off during winter , as among other things it keeps the compressor clutch deactivated and may give a slight improvement in mileage. However, as above, it does dehumidify and will probably keep the temp inside more exact if left on. It also sets up the vent motors in a slightly different way. If you decide to turn it off, turn it on for a short time once a month with the temp set to very low to circulate the refrigeration oil in the compressor and exercise the seals.
Super Member
Joined: Aug 2011
Posts: 861
Likes: 38
From: Philly area
350 GLK, C280
Thanks, I'll leave mine on. I drive a lot in the Spring and Fall with the windows and roof open. That probably lowers the mileage more than anything else I could do except drive with a roof rack on.
