One other note about heaters that David didn't mention, for those of you
concerned about the environment and squandering of resources (oh wait, we drive
big old gas-guzzling vehicles...), is that for every unit of electricity that
you convert completely to heat, a seemingly 100% efficient operation, 3 units
of some other fuel source are required to create it.  In other words, even if
you convert all the electricity to heat, you're still only operating at 33 1/3
% efficiency.  Electricity, a high-grade form of energy, is NOT a good way to
produce heat, a lower-grade form of energy, efficiently.  Better to burn
something like propane or natural gas . . .

Food for thought,
Marc Perdue