Another advantage of cornies, the sun don't shine in there!
I use a small electric space heater & blow warm air on the fermenter. I keep the house around 65F in the winter & have an electric heatpump, so I'm not really wasting the power. I have a 24 hours timer that has 48 pins to control when it is on. About 30 minutes on and 60 off works best.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk