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How to get a traditional hot water radiation system off oil

rattlingbooks | Posted in Expert Exchange Q&A on

I have a 3 story 1890’s building in St. John’s, Newfoundland that is in a state of incomplete renovation.  (UFFI insulation in exterior walls replaced with Roxul; knob and tube wiring replaced; replumbing almost complete)  It is heated by traditional cast iron hot water radiators with water heated by an oil fired boiler.

The oil tank has to be renewed within 2 months for insurance purposes.  It has reached its 20 year mark so despite looking brand new I am told I have to replace it. This will cost 3K for a steel tank (rated for 25 years) or 4K for a fibreglass tank that is rated for 2x as long.

I have been daydreaming about getting the building off oil but done nothing about it except postpone getting a chimney liner in case I retire the chimney.

The insurance deadline on replacing the oil tank has delivered my day of reckoning.

I have a Slantfin Electric Boiler (Monitron Electric Boiler; Model EH-18-135-S) in a box that I have been saving for years for …..now?

Have yet to identify someone to reach out to for a quote or advice locally.

Any observations or suggestions on strategy to share?

Thank you

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Replies

  1. Expert Member
    BILL WICHERS | | #1

    I would do a cost comparison between the oil and electric boilers before committing to making the change. You don't want to put in an electric boiler just to see your operating costs go up.

    Note that if you go with a fiberglass tank, they do last longer, but they are also much more prone to damage at install time. If you go with a fiberglass tank, be very careful not to stress it at all during installation, and make sure it sits evenly so that there isn't more weight on any one part of the tank in relation to the others. Stress cracking is the one big weakness with fiberglass tanks. If you install a fiberglass tank right though, it lasts pretty much forever since you don't have corrosion problems.

    Bill

  2. Danan_S | | #2

    > I have a Slantfin Electric Boiler (Monitron Electric Boiler; Model EH-18-135-S) in a box that I have been saving for years for …..now?

    Given that you already own the key component of the system, and Newfoundland appears to have crazy cheap electric rates ($.13/kWh in St. John's according to your utility website), and given the very high price of fuel oil, I'd hazard a guess that the economics of going electric make sense.

    I'd add a storage tank, however, so that you can slowly heat water and store it (which is kinder to the electric grid), which also gives you a buffer of hot water during a power outage.

  3. rattlingbooks | | #3

    Both very helpful observations. I am forewarned if go with fibreglass tank and I will plan to add a storage tank or at least design things so that it can be easily added later - if go electric.

    I am very motivated to go electric both for green house gas emmissions reasons and because I am pissed off at the oil and gas sector's behavior.

    The main limiting factor is cash flow and a gun to my head in the form of the insurance expiry of the oil tank to do it now instead of planning to do it later. But I guess it is a good thing if it gets me off the pot.

    One large downside I see functionally is that a small generator could run the oil boiler system in an electrical outage but not the electric boiler. However, we rarely get very cold temps here in eastern Newfoundland; it's just a huge part of the year spent hovering around zero degrees Centigrade and the suite of precipitation forms that come with that + freeze / thaw / freeze / thaw so many times we should be testing building products - "survived a thousand winters in a year!" - that gives us a bad name. So the heating system is not so cold as it is long and wet.

    I value keeping the cosy warmth of cast iron rads. There are two 200 amp services so it is the cost of switching and finding out if there are any smarter details to be paying attention to when I look for a quote and specs.

    Thank you

    1. Danan_S | | #4

      > One large downside I see functionally is that a small generator could run the oil boiler system in an electrical outage but not the electric boiler.

      Just get a propane tankless water heater as a backup if you are concerned about grid outages (Marey makes ones that only need a battery for their ignition circuit, so no grid required) . Put it behind manual selector/diverter valve.

    2. Expert Member
      BILL WICHERS | | #7

      >"I am very motivated to go electric both for green house gas emmissions reasons and because I am pissed off at the oil and gas sector's behavior."

      I think your region's electric supply is primarily sourced from hydroelectric sources, in which case you WOULD likely reduce your overall emissions with an electric heater, even using plain ol' electric resistance.

      You MAY be able to run the electric unit with a generator, but it would probably be a decent size generator. You'd either need propane or diesel as a fuel source for the generator, with propane's advantage being it lasts forever and does not degrade sitting in the tank, but the downside (compared to diesel) is that propane has lower energy density, so you need more of it for the same amount of generator run time. If you don't have very many power outages, then propane is probably a better option, especially since you can also use it for a backup heat source if needed.

      I like DC's suggestion of an air to water heat pump. If you have both cheap electricity AND don't usually see extremely cold outdoor air temperatures, you're really in the perfect place to use a heat pump for maximum energy savings. You would also be able to run that heat pump with a smaller generator if you want a backup power source.

      Bill

  4. DCContrarian | | #5

    The long term play is switching to an air-to-water heat pump, it will use somewhere between half and a third of the electricity of your electric boiler, especially in your mild climate. The problem is the technology isn't quite there yet where you can just drop one into an existing system, and two months isn't a lot of time. Plus you've already got the electric boiler.

    1. paul_wiedefeld | | #6

      Agreed, the electric boiler should be a stop gap. If you use a lot of oil now, then the air to water heat pump makes more and more sense. You can still keep the electric boiler to supplement if need be.

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