nattarbox t1_j1zjx78 wrote on December 28, 2022 at 3:59 PM

Don't have direct experience, but a few anecdotes that might be useful:

My parents swapped from oil to propane (forced air furnace), but propane prices went up at the same time in Maine and it ended up being a wash on fuel savings. They supplement with heat pump minisplits which helps with costs a lot and makes the house cozier.

If you haven't looked into it, Mass Save is offering big rebates to convert from oil to fully electric (heat pumps). There are also heat pump options for electric water. Might be worth a pricing out to compare against propane, but with rising electric costs I'm not entirely sure what the best option is anymore.

I swapped from an electric water heater to an on-demand natural gas boiler. I like it a lot better (unlimited water, more reliable, freed up space in the basement), but the energy savings were pretty negligible. Hot water energy costs are like a rounding compared to home heating.

Dont_Mind_da_Lurker OP t1_j1ztssr wrote on December 28, 2022 at 5:06 PM

Hi, yes, we're working with HVAC companies to put in heat pumps which will become our primary heat source instead of our oil boiler... But every HVAC company has recommended we keep a backup heat source in case it gets too cold for the heat pumps, or if there is a breakdown in the heat pump equipment that can take a few or several days to repair and we wouldn't want to be without heat in the meantime... Since we have existing radiators from our boiler, they're all saying keeping a boiler as backup will be the best option... but our boiler is near end of life, and not providing enough hot water, hence this whole line of questioning and research about oil boiler vs. propane boiler.

nattarbox t1_j205b21 wrote on December 28, 2022 at 6:21 PM

Yeah not having a backup seemed like one of the sticking points for going all heat pump to get those rebates. My parents went with two condensers, so if one goes you still have the other. Something like that + cold weather heat pumps + a generator would keep you going through most any situation. Still have rising electric costs to deal with though.

If you have to keep propane in the mix, I'd go for the combo on-demand boiler, just based on my experience having a natural gas version. It cut our therms in half vs a standard older gas furnace, hopefully you'd see similar efficiency with propane. And if the minisplits are doing the heavy lifting on heat, your gas needs could be pretty minimal. There are still some valuable rebates available for a setup like that.

Dont_Mind_da_Lurker OP t1_j20l2qo wrote on December 28, 2022 at 8:05 PM

Yeah, that's pretty much the direction we're heading: Cold weather heat pumps are primary heat, need backup heat when it's too cold for heat pumps, need some source of hot water (same fuel/system as backup boiler, or something entirely different?)... Sounds like we may be on the right track...

The HVAC guys are telling us a combi unit wouldn't work well for our usage, so they're looking at tankless water heater as one unit, backup boiler as a separate unit... but we did ask about the combi units.