The air conditioners that have both heat and cool modes only heat at 60°F and above. They do not switch from cooling to heating automatically.

One solution that CoolBot has found is to buy a little heater (buy the blower type, not the radiant type) like the Lasko Ceramic Heater or the Pelonis ceramic heater. Plug it into a pass-through thermostat like the Inkbird ITC-308 Plug and Play Temperature Controller, which is digital. The Inkbird is easy to use and to adjust. For instructions on how to set the Inkbird with the CoolBot, check out their blog post “How to set up your cooler for the winter season.” 

A second option is the DuroStat Portable Waterproof Prewired Thermostat from FarmTek.com (Item #CR2045). This one is not digital like the Inkbird. Some of our customers have used the AGPtek STC-1000, but this is not a plug and play like the other ones. Make sure you choose a thermostat that can be set below 40°F.

Whichever thermostat you choose, CoolBot recommends setting the CoolBot at least 4°F warmer than the heater so they don’t overlap and fight with each other.