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Help choosing the right gas boiler

OmegaNorth Member Posts: 2
edited April 2019 in Gas Heating
A little background first. I graduated a 2 year plumbing and heating trade program in 2016 and worked for a service company for about a year before deciding to leave the industry and join the family business. Now I have purchased an old farmhouse in central Maine that needs a ton of work. I am in the process of renovating it now, and I am trying to save some money by running plumbing/heating/electrical myself.

I am going to be replacing windows, and sprayfoaming the walls, and putting blow-in insulation in the attic. I have yet to do a heat loss calc, but I am thinking its going to be a 80k system. I am planning on sitting down with a pot of coffee and doing a full heat loss calculation in the next couple of days. I do know that I will be firing the boiler with gas.

My current dilemma is trying to decide between a modulating condensing boiler or an old faithful cast iron. I wasn't in the industry very long; but long enough to go to a couple trade shows and read some textbooks about the new highly efficient mod/con boilers. I like the idea of using less fuel, but not entirely sold on the fancy heat exchangers being reliable long term. I also don't like the idea of a board going bad leaving me helpless compared to a conventional burner control that is easily replaceable. I am leaning toward heating with baseboard, although I am intrigued by the newer panel radiators. I also will be installing mini splits in the home to aid with heating and provide cooling.

I have been out of the game for a while, and when I was in the game I was sitting on the JV bench. I am looking for some varsity professionals for advice. Am I misguided on my preference toward cast iron? If not what manufacturers are known as reliable? In trade school I liked Burnham and Buderus. Also has anyone had any experience with the panel radiators?

Thank you in advance for your wisdom.


  • Intplm.
    Intplm. Member Posts: 1,443
    Heat loss calc is a good start, so your doing the right thing there.
    Between mod. con. or "old faithful cast iron". ? My thoughts tend to leave me at the old faithful, especially if you are up in the beautiful state of Maine. Gets and stays a darn bit cold up there. Even if you are installing the mini splits to help with heating in the winters, reliable cast iron boilers are just that. Reliable. Burnham and Buderus are good choices. And parts availability is less of an issue. At Least in my experience.

    Heating with baseboard is fine but have you considered installing radiant floor heat?
  • ScottSecor
    ScottSecor Member Posts: 679
    I agree, heat loss calculations are a great start. However with an old farmhouse in central Maine your going face some real challenges.

    For example A;, I just did a quick search of design temps for Maine and came up with -9 degrees F. I would guess that the typical (original) two thousand square foot 150 year old farmhouse has single pane windows, loose fitting doors, no insulation, etc. With this type of home I would guess the "average" room would require about 10,000 BTU's to heat house to seventy degrees at design conditions. This same average room would require roughly eighteen feet of hot water baseboard with 170 degree average water temp.

    Example B; Same house, same location but you decide to gut home, 3.5 inches of spray foam (minimum) every wall, 10 inches of foam in the ceilings, all new triple pane high end windows, new doors, new siding with two inches of foam underneath, etc. You install radiant low temperature radiant heat instead of hwbb. Same "average" size room now only requires 3000 BTU's to heat house to seventy degrees at design conditions. Again just guessing off the top of my head, but I think you may be able to run your average boiler water temps at say 110 degrees.

    You have to determine (shall I day guess at this point) how far you are actually going to go with regard to improving the home. For example A I would suggest cast iron boiler with hwbb, or cast iron recesses radiators. For example B I would suggest mod con with low temperature radiant (floor/wall and or ceilings).

    I suspect you'll probably fall somewhere in the middle of my extreme examples above, especially if you do not have unlimited funds.
    HVACNUT Member Posts: 5,025
    Your emmiters and design will determine if a mod con is even feasible. But if it were me, not that my opinion should mean diddly to you, I'd go for reliability over efficiency any day. Atmospheric cast iron or an EK-1 Frontier Gas. But that's not a DIY system.
    And because you're DIY, when you're done you absolutely need a pro to come in to set it up properly and do a combustion analysis.
    Research circulator requirements after the heat loss calc. Slant/Fin has a free app you can download.

    Why blown insulation in the attic? New and newer homes by me also spray foam the underside of the roof. 80° in the attic in August. Nice. Nothing between the ceiling joists. Only 3/4 plywood on top for the nice HVAC guy or gal.
  • OmegaNorth
    OmegaNorth Member Posts: 2
    Intplm: Thanks for the response! Regarding radiant floor heat the house has pumpkin pine flooring that we are going to try to restore throughout. I didn't think radiant floor heat would be efficient with this setup, am I off base on that assumption?

    Scott: You bring up some good points, and we do fall somewhere in between your two scenarios. Spray foam on the walls, new windows, new doors, spray foam and insulate basement. We are opting to replace clapboards as needed for the time being, with a plan to redo siding somewhere down the road.

    HVACNUT: I actually have an EK system in my current house, and I think it's a great setup. This will be a DIY job for sure as we have overextended on this old farmhouse. I am almost through with demo and every day I wonder why not tear down the shell as well and build new with the amount of renovation that needs to be done. That being said even though I have the ability to get my gas license with a check to the state board I am limited to what boilers I will have access to. More than likely I will find a reputable contractor who will agree to let me run the piping/electrical, and let them handle the commission and setup of the boiler.

    EBEBRATT-Ed Member Posts: 13,440
    I vote for a Peerless or Weil Mclain conventional boiler.

    You have the advantage of having the technical ability of learning about any Mod Con you install if you go that route.

    That leaves the question of parts availability & pricing and longevity. Parts are expensive and we have all had horror stories about availability. A few pieces of electric baseboard for back-up isn't a bad idea
  • Zman
    Zman Member Posts: 7,446
    My next house will be a combination of panel rads and radiant floors,wall,ceilings. Designing your emitters for low water temps will future proof the design. Solar thermal, heat pumps and condensing boilers will be far more efficient if they can run at low temps.

    You are wise to consider availability of parts, but remember, any modern boiler has proprietary controls and parts that can go bad at any time. You might consider talking to local supply houses to find out parts availability of the models you are considering.

    The Lochinvar WHB85 would be one worth looking into.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Jersey2
    Jersey2 Member Posts: 150
    I'm not sure that spraying foam on the underside of the roof of an older dwelling is a good idea. Any moisture or roof leaks might get trapped and rot the roof.
    I'm not a plumber or hvac man and my thoughts in comments are purely for conversation.