Originally Posted by Dapplecreek
Especially if you find someone scrapping a mobile home nearby...
or a used WH from a travel trailer or RV.
or....a spa heater, which is merely an "inline" electric residential WH without a storage tank. Since you need a circulating pump, you really do not need the storage tank (and weight) of hot water.
Unless you want heat "right now" versus in a few hours.