Which quail require heat? None. Provided they winter in a draft free shed, barn, or shelter.
Here in the "Great White North" of Quebec we had 3 weeks of -30 Celsius or -20 Fahrenheit. the only problem is having a suitable water source that gives half a day of drinkable water.
I found a heated dog water bowl that I used for my ringneck pheasants and bobwhite quail. I had a steel heated water fount base with a two gallon plastic water fount on top. The fount would freeze solid if cold enough (i didn't fill it beyond half full) and would exchange with a non frozen one with room temp water. Had the birds on lights so they had 6 hours or more of light after being fed and watered. I did not lose any bobwhites, or coturnix quail. they were in a shed, on shavings on the ground.
Of course they didn't lay eggs until things had warmed up.
Save your money, don't heat them, heat the water.