I did the same sort of back of the envelope thing last night and got about
the same numbers as Ray. When the heater is running you will be using the
juice that would be required to light 100 60W light bulbs. If your house
has the normal 200 amp service, this unit will require over 10% of that
service when ever it is on. Depending on the area, electric heat can be 3
to 4 times more expensive to run then gas, oil or propane. The extra cost
of installing one of these non electric heaters will often be paid for in
less than one heating season. I know lots of people that are very happy
with natural gas, but for many of us that is not an option. I prefer oil to
propane because of the ethylene produced by burning propane (oil is also a
little cheaper per BTU). If you opt for propane, make sure the unit is
power vented.
Pat