winter is coming!

Sorry you can use USB hotwater bottle so its more easy

Lights on at night or if you love and want to keep them more happy heat mat or use hot water bottle

si las temperaturas son extremadamente bajas plantéate utilizar bombillas de sodio, puede que aporten el calor necesario

I ran the Ventilation in a closed system when my heater broke. Bought a heatmat in case it happens again

run lights at night. less work heating at night and lights help generate heat. use that room more... bring your laptop in there, lol... run your electronics and anything else in that room to generate heat, bwahahaha. The co2 from your presence will probably be more useful, than all that effort, space heater or other things plugged in that generate heat while performing a different intended function. no other way if your house temp is not warm enough.