Interior Car Heater With Thermostat Control

Updated 03/26/2026 | Published 03/23/2026

Products Featured in This Question

Kat's Heaters Vehicle Interior Heater - 150 Watt - 12V

(26)

$64.26

Kat's Heaters Vehicle Interior Heater - 900 Watt - 120V AC

(26)

$139.66

Question:

Does this heater come with a thermostat? Does it automatically shut off after reaching a certain temperature or does it simply run continuously? Thank You, Tom

asked by: Tom

Expert Reply:

Hi Tom, that’s a great question and definitely something worth checking so you know exactly what to expect.

The Kat’s interior heater part # KH37650 does not have a built in thermostat, so it will not automatically shut off or cycle once it reaches a certain temperature. It’s a simple 12 volt heater that provides constant heat whenever it’s powered on, so it’s essentially just on or off with no temperature regulation.

I know that can be a concern if you’re hoping for something that maintains a set temperature, especially for longer use. If you are looking for a heater that does regulate itself, we do have options like the Kats heater part # KH37100, which includes a thermostat, but it does require a standard 120 volt outlet instead of a 12 volt plug.

If you can share how you’re planning to use the heater or what kind of power source you have available, I’d be happy to help you find the best fit.

expert reply by: Heather A

Tom

3/26/2026

Thanks for your reply Heather. I have a furnace in my Class B camper van but when I'm camping in 0 F temperatures the plumbing in the aft cabinet freezes. I tested one of those compact 12 volt 100W PTC "incubator" heaters connected to a separate 10A digital temperature controller from Amazon because I prefer that the heater not run continuously, since I only need it to keep the cabinet about 40 F. I tested two of the controllers with the 100W heater and unfortunately they could not handle the 8.3 amps because they both failed after about 10 hours of usage. I already have 12V power switched in the plumbing cabinet so a 12 volt heater that would shut off above 40 F would be ideal. I have a 6" W x 8" H x 8" D space in the cabinet for the heater. Thank You Heather! Tom

Heather A.

3/26/2026

@Tom You’re definitely on the right track with that setup but we do not carry what you need. But I can tell you what likely caused the issue is that those small temperature controllers aren’t really rated for continuous loads at that level. Even if they’re labeled for 10 amps, best practice is to only run them at about 70 to 80 percent of that capacity for continuous use, so around 7 to 8 amps. Your heater is right at that limit, and over time that creates heat inside the controller, which can cause the internal relay to wear out or fail, especially in an enclosed space. A much more reliable way to run that setup is to use your temperature controller to trigger a relay instead of powering the heater directly. In that setup, the controller only sends a small signal to the relay, and the relay handles the full current going to the heater. That keeps the heavy load off the controller and puts it on a component that’s designed for continuous duty, which makes a big difference in long term reliability. You could also step up to a higher rated controller in the 20 to 30 amp range, but even then, using an external relay is generally the more durable solution. A simple 25 or 40 amp relay is inexpensive and should solve the issue you ran into with the controllers failing.

Tom

3/26/2026

@HeatherA Thanks for the tip Heather! Will do!