I also have an
electric heater that keeps a daytime temperature of 80 degrees F. and nighttime temperatures of 65 to 70 degrees F. With lighting at 20 to 30
watts per square foot, waste heat from the lights does much of the heating.
Of course,
electric coffee makers don't run all day long at 1500
watts,
electric heaters are all pretty much the same efficiency, every
electric heater in the United States has to have Underwriters Laboratories approval to be sold, and 5100 BTUs is exactly 1500
watts, which everyone understands to be a circuit breaker full of electricity.