I'd like to start regulating the temperature of my beers and meads during fermentation, and have been looking at kits like the Mangrove Jack's Temperature Controller.
However, judging by the description it can only be used either in heating or cooling mode not both at the same time.
I'm doing my brewing in a garage, which can get quite cold at night (5 degrees) but also quite hot during the day (35 degrees) as the garage door is exposed to direct sunlight.
How can I (cheaply) keep my fermenter at a steady temperature under these conditions?