Slightly off topic but somewhat related....
I have a 15,000w dayton Portable heater with a wall mount. I figured at $.171 per kWh it would cost about $2.57 per hour of continuous running. It works well. So well that I pulled one of the coil bank fuses to drop it to 7500 W.
Electric is the most expensive form of heat but it is practically 100% efficient. I use a propane portable to take the chill off and the electric heater to maintain the temp.
It also has a fan only option that can and will be used when the temp is higher.