A friend of mine wants to get a portable heater that can keep the area warm, here in Portland,,so not really ccold... . but also wants to not be just a small 1500 watt space heater... . he wants it to be able to heat a 400 sq ft garage - and even with the door open... . obviously not as warm,,,,but still some fair amount of heat, Now don't ask me why..... but this was his question. Now he'll probably have to compromise... . but what is out there - propane---oil etc???