Air-conditioning Versus Vent While Parked

[SDRick]

With summertime temperatures rising, I have a few questions about interior temperatures while parked.

In a general sense, how much range is lost while you have air-conditioning running while parked in the sun? And if you plan on using the AC while the car is parked, is it better to also place the sunroof and vent position?

 

[jelloslug]

If you are just going to be a few minuets in a store or something like that you will use less energy overall by leaving the AC on. It take more energy to cool the car back down than just keeping it cool to begin with.

 

[mspohr]

I noticed an odd thing a few days ago. Car was parked and off and all windows closed in hot sun. I heard the climate fan blowing full speed. It stopped when I opened the door but resumed after I locked the car up again.

 

[gavine]

AC generally uses about 2 to 3 miles per hour, depending on outside temperature, sunniness, recirc or not, etc.

 

[supratachophobia]

I noticed an odd thing a few days ago. Car was parked and off and all windows closed in hot sun. I heard the climate fan blowing full speed. It stopped when I opened the door but resumed after I locked the car up again.

I've noticed this happening of late too.

 

[GlmnAlyAirCar]

If you are just going to be a few minuets in a store or something like that you will use less energy overall by leaving the AC on. It take more energy to cool the car back down than just keeping it cool to begin with.

As long as you suspend the laws of thermodynamics.

 

[chillaban]

As long as you suspend the laws of thermodynamics.

I don't think "less energy" is true, but closer to the same amount of energy than you might think. The car has an electric compressor, and not like an electric motor, it's much more efficient at lower operating points (e.g. maintaining an already cooled cabin) than extremely high operating points (when it sounds like a turboprop plane with the more recent updates).

It's not the same as a home HVAC system, which really only has two operating points (some homes only have one): Slow and efficient, or slower and more efficient.

 

[mspohr]

As long as you suspend the laws of thermodynamics.

Agree. Car w/o AC on will quickly reach equilibrium temp and require no additional cooling when you get back so best to leave it off.

 

[BrokerDon]

Best advice in hot sunny weather is keep the sun off the glass, especially the windshield. We attach a $39.99 Intro Tech Snow Windshield Shade Intro-Tech Automotive Windshield Snow Shade on the OUTSIDE of our windshield to eliminate 99% of the "greenhouse effect" solar gain through the windshield. We also Vent the sunroof if we're going to be away for a while to keep the interior temperature about the same as the ambient air temp. Then we typically turn the Tesla Climate Control ON using the Tesla iOS app about 5 minutes before we get back to our car.