BeerBorg

Got the fermenter pails on the table in the basement brew room. Got a couple blankets draped over them down to the floor. Electric oil heater under the table. It's 58degF in the room, and 70degF under the blankets, with the heater on real low and the termostate having it off most of the time.

In between brews, I unplugged the heater, and it took about five hours for the space under the blankets to get down to room temp.

Electric bill ain't goin' kablam this winter, I can tell you that.

If you use Nottingham, you can ferment down to 57 readily and even lower if you use enough yeast. I know US-05 is only supposed to be good down to 59, but I've fermented with it lower than that.

I ferment in my basement (on the floor) and it's typically in the mud 50s in winter. Nottingham chews right thorough at that temperature.

Yep, I use Notty all the time in the winter, with 57 degree ambient temps.

It has no problems at all.

Wyeast Kolsch yeast will work great at low temps too for a nice clean fermentation.

I use Notty or S04 in a cool basement.
I have had an off flavor (peach) with US05 under 64, though it may be that I made another error.
You could probably use 34/70 at that temp.