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Can I replace my Oil Boiler with a Heat Pump System?

saltiel Member Posts: 1
I have a home in second Southern Maine on the ocean, which gets it's heat from an Oil Boiler (Biasi) which was installed about 8 years ago. The home is 3 stories, 2500 sq feet with a basement. The oil system with forced hot water works fine but I would like to go with something more environmentally friendly and, hopefully, cheaper to operate, at the same time. We have baseboard radiators throughout the home, a couple of fan driven heaters (heated by the forced hot water) and 5 zones.

I am interested in the idea of using a heat pump system, perhaps keeping the oil boiler as a backup for those couple of weeks when we get very low temps in the winter. (Being on the ocean does moderate the temperature quite a bit.)

Is this a sensible way to go? The house went through a thorough renovation about 20 years ago (long before we bought it) and is well insulated with all new Andersen windows throughout. There is a lot of passive solar heating during the day unless it's overcast outside.

What do you all recommend?


  • Jamie Hall
    Jamie Hall Member Posts: 17,025
    Probably not directly, but it depends on what water temperature your existing system runs at. There are a few air to water heat pump systems available for heating (the ones for domestic hot water don't heat the water hot enough), but reaching normal heating system water temperatures is a bit of a stretch.

    What you can consider, however, is keeping the existing system just as is, and adding either a central -- or more easily, a minisplit -- heat pump system for most of the heating, which could also provide air conditioning if desired. While it's unlikely you'd recover the capital investment in any reasonable time frame, it might -- or might not -- be cheaper to operate.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • GW
    GW Member Posts: 4,302
    edited April 2020
    Jamie not sure what’s what he asked- maybe he means adding a new and separate heat pump strategy.

    Oops I see you did talk about that. It’s extremely unlikely a heat pump would work with his existing system, isn’t 140 or so the max on those systems?

    “Cheaper to operate” you do know oil is cheap these days? So these days the answer is “no”. That whole topic on non linear, it depends on the costs of the fuel and electricity, comfort levels in all areas of the home (bathrooms, if you’re considering mini split units), and if the HP system(s) will do its job at super cold temps.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • pecmsg
    pecmsg Member Posts: 2,314
    You can install Mini splits but be advised as it get colder outside the heat output drops. There fine for spring and fall but middle of the winter you'll be using the oil hot water!
  • Ironman
    Ironman Member Posts: 6,554
    I would recommend that you start by having a good oil boiler tech come and make sure that the burner is properly set up/adjusted, the boiler is clean, and it has some form of Outdoor Reset (ODR). Also, make sure the fins on the BBs are clean and the covers on correctly. These things alone could save up to 30 or 40% depending upon the present condition of the system.

    To know how much heat is needed and what size equipment, you would first need a SCIENTIFIC heat loss calculation to be done like an ACCA Manual J.

    That being said, I would'nt even consider REPLACING the oil system with a heat pump(s). Supplementing it, yes. Replacing, no. And as mentioned, mini splits may be the best option.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    JUGHNE Member Posts: 8,927
    As Ironman said above.

    Minisplit heat pumps would run more economically for the mild weather.
    I would only size them for that purpose otherwise oversizing for the worst weather would just be a waste as you need some back up heat anyway.

    The HP will be more "environmentally friendly" perhaps only in your back yard.
    If the main reason is to be Green, then where does your electricity come from? Gas, coal, hydro etc.?

    Electricity generation and transmission usually has a dismal efficiency rate that makes an 80% oil burner look good.
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,301
    Your properly tuned Biasi is pretty efficient, and very clean burning.
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,385
    You can use Bioheat and have an immediate impact on your carbon emissions with no upfront investment. B20 which is 20% biodiesel is available in your area.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    HVACNUT Member Posts: 4,187
    I take the meaning of "backup"
    from the OP as staging.

    The math using oil vs electric might make you toss that idea right in the trash.

    Do these 5 zones also have air conditioning?

    If yes, then sure. A high SEER/EER Heat pump can work with staging. The oil system will take over when the heat pump cant do it. I would set it up based on outdoor temp differential rather than thermostat differential.

    A competent HVAC contractor would know if its feasible. Make sure ductwork is sized correctly, do a heat loss calculation, etc.

    It's probably a good bet the Biasi is oversized so that's where you should start if you're looking to save. Like @STEVEusaPA alluded to, your property sized and tuned Biasi (what burner BTW?) will burn efficient and CLEAN. If you smell anything or see even a speck of soot then something is wrong and it needs addressing.

    The part I don't like is having no heat during defrost mode. Electric heat during defrost is typical but that's a lot of extra work and money for just a couple minutes per hour or so.
    JUGHNE Member Posts: 8,927
    For dual fuel I like to set controls so that the HP shuts down before a lot of defrost cycles are necessary.

    BTW, is ocean salt air a concern for outside AC/HP coils?

    Just asking, I am as far away from salt water as one could be so have no experience with that.
  • jumper
    jumper Member Posts: 1,710
    How well does the zoning work? Does it keep unoccupied rooms at 55°? Most of people's time is spent in family room and kitchen. So zoning can be key to economy.
  • Jamie Hall
    Jamie Hall Member Posts: 17,025
    Ocean salt air, @JUGHNE , is murder on anything metallic. There are a few stainless steel alloys which aren't bad. Bronze... that's about it.

    Why do you think there's a saying in the Navy -- if it moves, salute it; if it doesn't, paint it.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England