Temperatures across most of the country are currently homebrew-friendly, but I'm already planning for winter. I have a 7 cubic ft freezer in my garage with an external thermostat that I use to brew to temperature control my fermentation. I can make the freezer as cold as I want, BUT I don't have a way to add heat to the freezer once garage temperatures dip below brewing temperatures.
I don't want to ferment in a closet and don't want to only brew lagers all winter. Any ideas for safe, cheap ways to add heat to my garage freezer so I can keep fermenting at ideal temperatures all year long? Thanks, guys.