CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Will parking a warm truck in the garage on a cold day make the garage warmer?

Suppose my unheated garage is 35 °F and it’s 15 °F outside. Then I go drive around for an hour or so, like to Home Depot or something, and then park back in the garage. The engine and transmission got warmer but the whole rest of the truck body got colder.

Do you think the garage temperature will go up or down as a result?

Depends what store you go to. The best is liquor store. Warms up garage the best.

Why don’t you just do that and measure it yourself ? I seriously doubt that even if it did raise the temperature it would be very slight and short lived.

1 Like

Heat travels to cold things. If the garage is colder than the truck it will warm if the garage. The garage’s heat will travel through the walls and door to the colder outside.

And none of this matters much at all.

1 Like

Opening the garage door twice will cool the garage.

The warm engine and exhaust will warm the garage. The now colder rest of the car, which weighs more than the engine and exhaust, will cool the garage.

Did the car sit in the sun? What color is it?

1 Like

My biggest question is who cares :question: There are definitely more pressing issues i need to worry about.

4 Likes

I was thinking of trying to clean up some spilled coffee mess and wondered if it would be better from a comfort perspective to do it before driving around or after.

  • Yes, I could measure it myself. I’ll try that. And I’ll bet the wall thermometer will change by zero.
  • Yes, opening the door is probably a bigger thermal shock than the truck coming and going. The truck is black but after driving I’d assume that the bodywork is not affected by sun warming.
  • Who cares? Obviously you care since you replied! Come on, this is a General Discussion and we are discussing.

but not about thermodynamics.

It depends on the initial mass, the heat transfer rate and the ambient temp of your garage but from someone in the Mid Atlantic where anything under 32 degrees means “Shelter In Place”. :slightly_smiling_face:

But more seriously I’d worry more about the change from ice to water, where you’re promoting rust, a chemical reaction that occurs more under warmer temps than colder temps.

When you consider how long it takes a central home heating system to warm a house to 72 degrees from 68 degrees expecting a vehicle to have any measurable effect just pulling into a cold garage is expecting way to much.

3 Likes

I’ve got a thermometer in the garage and really haven’t noticed any difference. I think what little might be gained is lost by opening the door. I’m fully insulated though which helps more than anything.

At 15 degrees you won’t get much heat but at 35 I get lots of heat. If I work a little in the garage I’ll do it after the hot car sits for 15 minutes. It helps.

Probably not a lot.