So, what is the answer here? With such a big heater, would i be wasting alot of propane just firing it up over a smaller one? OR is the bigger going to be more efficient....So, whats the vote? Keep it or sell it and get a smaller one?
Now you thinkin Leeboy......here is my assessment.
1) Your 840 sq.ft shop only needs about 60,000 BTUs to heat it.
2) The free heater uses 200,000 BTUs to create 160,000 BTUs. That's an 80% energy efficiency.
3) As an example; the Modine Hot Dawg HD75 uses 75,000 BTUs and puts out 60,000 BTUs. That's an 80% energy efficiency rating also.
Now, that's BRAND NEW specs, therefore you can bet money on it, the free unit has lost some of it's efficiency. Yes, they have the same new efficiency "FUEL" rating, but what about the ELECTRICAL efficiency rating. The bigger unit will cost more in electricity.
Now it's simple math.
In BTU's, it should cost the same in fuel as both units are 80% energy efficient on the fuel and both will require 60,000 BTUs to heat 840 sq.ft. The free heater will heat it faster(bigger blowers ??), however it will also use more electricity to turn the blowers than the HD75.
THe HD75 has a 1/12 H.P. blower while the free unit has
TWO ???? H.P. blowers. I couldn't find the specs, but from the looks, they are larger than 1/12 H.P.
So, it's more than likely going to cost more to "run" over shorter periods than the properly sized unit will cost to run a few minutes longer.
Just my 2 cents as a Building Official as I see the sizing spec's on buildings all the time. Sell the two 160BTU units, size and buy your heater according to your building as overkill costs money in the long run.
