All the talk about efficiency, lightbulbs heating the house, etc. Makes me think about water heater efficiency.
I assume, the published efficiency of a water heater is what it takes to keep the water at the set temp vs the entergy input. So anything getting out of the heater thorugh the insulattion is a loss.
This may be true in the summer, when you don't want to heat your basement. But in the winter, the losses into the basement are not real losses, as such.
I'm wondering: is the heater transfer from the gas burner to water more efficient, than by comparison heat transfer from furnace burner to the air (assume 80% furnace, no fancy controls).
Reason for this question is: Does it really make sense to insulate the water heater and hot water pipes, as some people do, in the winter ("blanket" type)?
My guess is that one can remove heat from the heater exchanger of the furnace faster, than transfer it to water