Non-Condensing Boiler Questions

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New Member
Aug 29, 2021
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My home's gas water boiler broke after 35 years (original) and am looking to replace it. I noticed that I have two options: condensing (+90% AFUE) and non-condensing (~80% AFUE) boiler. I am leaning towards getting a non-condensing boiler because:
  • Non-condensing boiler is cheaper to purchase and install
  • Non-condensing boiler is less complex (minimal computer technology, less parts) so therefore would be cheaper to maintain and have a longer life-span
  • Condensing boiler will save ~20% on my gas bill (~$300 savings annually). Cost of condensing boiler and installation is ~$4500 more then a non-condensing boiler, which is a 15 year payback. I'm not confident that the condensing boiler will last that long.

My questions are:
  1. My local Home Depot, Rona, and Lowe's doesn't sell non-condensing boilers. Will it be difficult to find parts to fix a non-condensing boiler within the next 30 years?
  2. I turn the heat on for only 4 months of the year. Does this damage the boiler in any way as the system sits idle for most of the year?
  3. What should I be looking for in between different non-condensing boiler? Are there certain features I should be looking for? Should I be looking for an stainless steel heat exchanger?


Well-Known Member
Oct 16, 2019
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North Carolina
You live in CANADA and turn the heat on ONLY 4 MONTHS OUT OF THE YEAR? Must be some secret banana belt I don't know about...but I digress.

I had two, then three "boilers" in my car wash. The first two were Raypak 500,000 BTU; one for hot water (which used an 80 gallon storage tank, basically a deconstructed conventional water heater with the ability to deliver near-continuous hot water). The second Raypak, equal size, was for the floor heat (hydronic radiant deicing system). When I added a touch-less automatic, my hot water needs increased drastically, and the hot water boiler was replaced with a 1.2M BTU unit. All these Raypaks were atmospheric, non-condensing, about 80% efficient. That same Raypak design has been around for decades and the support is great. Don't know if they are approved for residential use, or if they have the CSA stamp of approval or whatever it is you need there. The floor heat boiler was over 20 years old when I sold the place, and still going strong. More importantly, from when the floor heat was needed (generally sometime in November) until it was warm enough to no need it (sometime in April) it was seeing a lot of use. In January and February, it ran nearly continuous. So the units are pretty robust. All mechanical, no electronics. Periodic cleaning and maintenance.

Where I was in the midwest there were specialty commercial suppliers of boilers; you did not get them at a home store.

There are a Raypak reps in each province: Raypak – International Representatives

In the car wash industry, prime users of boilers, by far the biggest name was Raypak.