Help with lean-to greenhouse purchase

[Bayard]

Hi WaterWitchin,
The greenhouse is heated with a Southern Burner (now discontinued) 24,000 BTU natural gas heater. It is adequate except for the coldest, windiest nights when I add an oil filled electric radiator to the cold end. The most we’ve paid for gas is $400 in a month, but that includes heating the house as well. I’m not happy with the options for replacing my Southen Burner, so I’m looking into a hot water radiant system to replace it. It would have a remote boiler and radiators with fins around the periphery.