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Community and Q&A

Backup Heating System Options?

Zins | Posted in General Questions on

We’re gut rennovating a home in southern NY and the main heating/cooling will be done with Mitsubishi Hyper Heat units. This is zone 5, R25 walls, R55 ceiling and pretty well air sealed.

The house has a previously existing propane fired baseboard system which I had intended to keep as a backup. Unfortunately, the boiler just crapped out so I’m now reconsidering the need for a backup heat source.

We don’t get much cold-cold weather here, I’m confident the hyper heats will keep us comfortable. But I like the idea of being able to fire up the propane when the power goes out, which does happen occasionally  here. Or even just turning it on in Jan and Feb when it gets colder.

Howeve, I’m not sure it’s worth the cost of a new boiler. I’d love to hear some thoughts on approaches others have taken. Go with only heat pumps? Put a new boiler in? Another option?


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  1. paul_wiedefeld | | #1

    The constraint will likely be your electric service: if you have enough service, an electric boiler or electric baseboard is cheap to install, expensive to operate, which is fine for backup. Otherwise, another propane boiler it is. You could get a lower efficiency propane boiler, since it’ll seldom run. Neither system helps if the power goes totally out, but a propane boiler plays better with a generator than an electric boiler. Wood is the most low tech and reliable, but you have to be available and able.

  2. freyr_design | | #2

    I would get a backup generator and use that if power goes out. This allows for a lot more than heat and probably wouldn’t be a huge amount more propane.

  3. Expert Member
  4. walta100 | | #4

    It is pretty hard to kill a boiler unless they are showing you a photo of a crack leaking water, I would get a second opinion.


  5. Expert Member
    DCcontrarian | | #5

    There's two kinds of backup:

    *Supplemental heat for when your heat pump can't keep up with the heating load.

    *Emergency heat for when the power goes out.

    Usually the most cost-effective supplemental heat is electric resistance.

    Usually the most effective emergency heat is having a generator, although if it has to power a heat pump it needs to be a lot heftier and have cleaner power.

  6. rockies63 | | #6

    Since you already have propane, I would do a small, direct vent propane wall heater which keeps the byproducts from propane burning completely outside the house.

  7. Danan_S | | #7

    I feel like there is a product idea here for a propane generator that reclaims some of the exhaust heat and uses it for space heating (obviously via some kind of heat exchanger that isolates the exhaust fumes).

    It would be similar to district heating using waste heat from thermal plants that they do in places like Scandinavia.

    Even better if it's also powering a heat pump.

    But if someone hasn't made it it's probably either infeasible or no market yet.

  8. WilliamLi | | #8

    The other thing to consider is local bylaws. Not sure what it's like in NY, but where I live the city bylaws say that every single room needs a source of heat. Even though I'm sure my ATW heat pump design, already over-built with 7 hydronic fan coils, will work to keep the house warm and cool when I want it, the bylaws here say that in the other 5 rooms sandwiched in between the 7 rooms with fan coils, I _must_ (not should) have built-in heat sources.
    So even though I don't think I'll need it, I need to decide whether I want to hook up the old hydronic radiators up to the new ATW system for show or put in a pile of electric radiant panels.

    1. Expert Member
      DCcontrarian | | #9

      You can usually meet that with a baseboard electric in every room. No law says you have to use them.

      1. WilliamLi | | #10

        Yes, that (baseboard electric) is what I'm almost certainly going to install; it's just the cost of pulling cable to hook up, and purchasing the things that I'm weighing up. Not that I'm weighing this for too long, either...

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