Portable heaters.

I'm using electric also, ProFusion 5600W it does need a 220 outlet though so that might not work for you. Does a nice job for area I use in garage, red heater next to it is older one that thermostat quit working. Saw a U-tube video a guy converted it over to a wall thermostat by using a contactor & transformer to get it down to 120. It actually works! I'm showing the black ProFusion which is newer but I'm actually using the older red one (looks like a science project gone bad)