mod/con with indirect or on demand water heater
Which is more efficient a Mod/Con With a side arm or a on demand water heater. My guess is the water heater with the condensing boiler.
A well insulated...
Indirect would be my choice. The combustion Eff. numbers will also beĀ a bit higher w/ the mod/con. Furthermore I am not a huge fan of having a boiler sit idle in the non heating season. kpc