Yeah, maybe the chart is just a theoretical plot, based on some odd-ball conditions.?.
I only know what I see on the metering.
Since I have no good way to measure the BTU output, the watt meter is all I can use.
Anyways, if
less power was needed (to heat your house) when it got really cold,
these things would be the
only way to heat!
Why waste money digging up the back yard for a ground loop??
