My house was 42F last winter winter. I used a fish tank heater + heating pads to keep my brew as close to 80F as possible.

However, I wouldn’t recommend using a heating pad in temps above the 50s. They emit a ton of constant, variable heat and it’s really easy to accidentally roast your brew. Try one of those reptile tank heaters that stick to glass. They’re way more stable. That’s what I used throughout the summer. You can buy a temperature control unit and set it to about 78F. That way, it’ll switch off it it gets too warm. They’re pretty inexpensive too. Grabbed mine on Amazon.

Edit with links to the products I’m referring to. I’m on mobile so forgive the sloppiness.

reptile pad

Temp control bc Reddit has a stick up it’s ass about using the linking tool for this one:

https://www.amazon.com/Century-Thermostat-Controller-Germination-40-108°F/dp/B01I15S6OM/ref=mp_s_a_1_1_sspa?dchild=1&keywords=reptile+heating+pad&qid=1604383752&sprefix=reptile+&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzTlAzOFlSMzdGOFJOJmVuY3J5cHRlZElkPUEwMTgzNTA2SjJHQVNIMFNEVlAxJmVuY3J5cHRlZEFkSWQ9QTAwODI1MzAyUFBLVEVOM1BMSzY1JndpZGdldE5hbWU9c3BfcGhvbmVfc2VhcmNoX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=