plantmanager said:That looks like a good setup, Chip. My greenhouse has leaks too, but our air is just too thin here at this higher elevation.
I'm at 7800 ft./2377 m. Never had a problem. The heater has a catalytic element and doesn't give off fumes like a kero heater. The solar setup and the electric radiant lamps provide about 90-95% of the necessary winter heat. I don't light the propane heater 'til it hits -10°F or the electricity goes off. Our power is all from a solar array anyhow, but the system is grid-tied and doesn't work when the line power is off.
To use propane, get a vented heater that draws air from outside and has an exhaust vent. We heat our house with a Qudra-Fire vented fireplace insert and also use a Bosch vented demand water heater.