Get an infrared lamp, like the ones used for baby chickens. They're insanely efficient at heating water (ie: your body), just make sure to not leave it on when you're not there as they are a fire hazard if not properly secured.
250W in infrared lamp heats a person better than a 1500W electric coil space heater can in a shorter period of time due to direct transfer of energy.
thanks. I'll work on creating a poll to transfer communities in a bit, lots of rl stuff going on.