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Oil burner vs. electric water heater

goshgo27 | Posted in General Questions on

It is a little late to ask this question because my installation of a new Boderus oil fired boiler starts in 30 minutes, so this more to torture me and maybe help others.

I had a new central heat pump installed 2 years ago at our place in MA and we use it as our primary heating and cooling source.  We switch to oil maybe 5 times a year during those really cold nights.  Our current boiler is also used for hot water, in conjunction with an indirect tank.   We are paying 10k for the new boiler and I wander if I should have had the boiler removed and switched to an electric water heater.  I know the central heat pump is not ideal at really cold temps but we’d run it regardless 99/100 days.  I looked into a heat pump water heater 1-2 years ago and was told I needed a huge open space for it work, which we can’t accommodate but I think the technology may have improved since then.   Did we just throw away 10k (minus what an alternate water heating would cost)?

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  1. Jon_Harrod | | #1

    The space requirements for heat pump water heaters are shrinking; State now allows you to use a space as small as 450 cubic feet without a louvered door or a ducting kit, and smaller than that with these accessories. See:

    1. goshgo27 | | #4

      Thanks Jon!

  2. greenright | | #2

    Yes you did. In my personal home I too had oil fired boiler with indirect hot water tank. Was using in average 45 gallons oil per month just for the hot water. 6 months ago replaced it with a Rheem platinum hybrid. Been running around 140–160 kw of electricity per month @ 30 cents per kw. Don’t know how the older hybrids were, but I am happy with the current crop- can’t hear it in the house (it is in the basement) and it is feee half ton ac in the summer… which I imagine is negated by the free half a ton ac in the winter… frankly at 55 degree exhaust air it tempers nicely with the air in the basement so it doesn’t bother me. I am sure there is some thermal penalty in the winter, but fuel savings more than offset those methinks.

    1. goshgo27 | | #3

      How much did you pay for the water heater with install and removal of your current system? Do you use a heat pump for heating the living space and are you in a New England like climate? The installer hasn’t showed up yet and if they try canceling, I will ask about canceling, although I’ve already given them 50% and I’m sure I’d lose some money to restock the heater. Thanks

      1. greenright | | #8

        I am in NE.

        I paid $2000 or so for the heater and did I self install as it is part of what I do for living. Your mileage will vary obviously.

        I have oil baseboard and hydronics for heat, but they sit dormant as my primary source of heat is a large Fujitsu Airstage VRF setup.

  3. paul_wiedefeld | | #5

    Heat pump water heater will crush oil fired indirect on operating costs. But it won’t provide any central heating if that’s important to you. Why replace the existing boiler at all? They should last nearly forever.

    1. goshgo27 | | #10

      The “block” rusted through. I was told it had to be replaced a year ago and I decided to wait until it failed. It was a major failure but it started getting really hot in my basement, which was from steam caused by a leak. My house is from the late 80’s but was vacant. Couple of years. Which is probably when the damage occurred.

      Thank you all for the helpful information!

  4. Expert Member
    BILL WICHERS | | #6

    You could use both, with the boiler preheating water going to an electric water heater. In this way, you get hot water from the boiler while it's operating (which is when the hot water from the boiler is probably the more efficient way to go), but you run on the electric water heater the rest of the time so that the boiler is running ONLY to make hot water. You might need some control logic setup with the boiler for this to work, but it shouldn't be too complicated to do. This way you get the best of both worlds.

    Heat pump water heaters can work in relatively small mechanical rooms these days, so that would have been an option too. Depending on your mix of operating conditions, you would want to choose between a heat pump water heater (high initial install cost, lower ongoing operational costs), and an electric resistance water heater (low initial install cost, higher ongoing operational costs) here. If you run the boiler a lot, the electric resistance water heater won't be as big of a hit in terms of operational costs, since it will only be running outside of the heating season for the most part. The higher your electric rate is, the sooner the switch to the heat pump water heater starts to make more sense.


  5. mr_reference_Hugh | | #7

    Did we just throw away 10k (minus what an alternate water heating would cost)?

    Well, you have a boiler. It most likely works. It is likely reliable. You likely appreciate it on those colder days. With that in mind, congratulate yourself for having made a decision to solve one of the problems on your list and.... move on.

    There are many decisions homeowners need to make over the lifespan of the ownership. There are going to be many more to come. Take this as a launch pad for making informed decisions for the next item, which is likely just around the corner.

    Enjoy the heat and your next informed decision!

    1. goshgo27 | | #9

      well put and thank you

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