HPWH with hydronic baseboards as supplementary heat method
Hi, all. I will start with the TLDR:
I want to get off oil and use a heat pump water heater for my hot water needs. I currently have a pellet stove and will be installing a ductless mini-split heat pump. Solar coming in March. Possibly a battery as well. House is in Massachusetts. We get sub-zero temps occasionally (1-2x/year). Climate Zone 5A. No natural gas available. Not interested in switching to propane.
The gap is my hot water baseboards which would be rendered useless/weak without the boiler since a heat pump water heater only heats to ~130f vs the boiler which is ~180f. Also, there is a closed-loop vs open system problem. Are there any ideas/recommendations on how to solve the closed loop and temperature problems? If the baseboards are not going to be my primary method to heat the home – does it matter if the temp is only 130f? Would they still provide enough heat to help heat the home without necessarily being capable of doing the job on their own?
Background: House built 1962. Original oil fueled boiler is still heating the house as the “primary” heat source. It’s old, parts are damn near impossible to find, and it is inefficient. Secondary heat source is a pellet stove. It is reliable, cheap to run, and effective, but no ventilation exists to send the heat from the stove to the other end of the house. Currently, we use the pellet stove as much as possible to avoid the cost of oil. So far this has worked pretty well.
Hot water is provided on demand by a built-in coil system in the boiler. No large scale storage tank.
MA has rebates between $1600 and $2400 for the mini split heat pump.
Sleeving my oil line and repairing my damaged chimney flue will cost ~$1800+. I can avoid these costs if I get off of oil, plug the flue, and remove the oil tank.
If I lose power, I will not lose heat due to the battery supporting the heat pump and pellet stove (the latter of which uses a small amount of power to operate the feeder system)
Heat pump water heater would be a cost-effective way to get hot water for washing + appliances, but not good for hydronic baseboads.
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