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Condensing water heaters

gaspr | Posted in Mechanicals on

I am referring to the Polaris type water heaters. Just looking for experiences using condensing gas water heaters. I have heard there have been problems with some units.

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  1. Robert Riversong | | #1

    I've heard of igniters having to be replaced annually, and the warranty covers parts for only 1 year and only first instance of failure (unless that's changed). It's a quality unit but very pricey for a stand-alone water heater.

    If you're considering a single unit for both hydronic heat and domestic hot water, you might consider the new Triangle Tube Excellence, which is a modulating, condensing wall-hung boiler with a built-in "tank within a tank" 15 gallon water heater. It's not only more efficient than a non-modulating burner (uses an outdoor setback sensor) and will likely last longer at lower burn rates, but provides more hot water than a tank-type heater and more reliable hot water than a tankless.

  2. gaspr | | #2

    Thanks Robert...I have looked a bit at Triangle's website but I am confused as to whether a separate indirect hot water tank is necessary for DHW?

  3. Robert Riversong | | #3


    I think it would depend on your maximum hot water demand. If you have multiple bathrooms with multiple simultaneous showers (and maybe the washing maching and dishwasher running as well), you might want an indirect tank with more storage capacity. Of course, that also means more standby losses, though that is minimized by the high insulation levels in these tanks.

    But the new Excellence combination boiler seems to have enough first-hour and continuous output to satisfy most smaller homes.


    The issue I have with the Polaris is the cost. I'm seeing them at over $3,000 when the Quietside ODW 120 is under $1,200 (and I've paid less than $1,000.) What are people really paying for these things?

  5. Robert Riversong | | #5

    The ODW 120 is a demand heater - the Polaris is a superinsulated tank heater. Apples to oranges, no? But I do agree that the Polaris seems to be overpriced.

    Quietside does make a combi demand heater, the DPW series, which is somewhat comparable to the Triangle Tube Excellence, though the latter has some wet storage capacity and seems to be higher quality construction.

  6. Steve Hoiles | | #6

    I have been focusing on building a tight thermal envelope for a 2900 sq ft, 3.5 bath, 5 bdrm home in order to create efficiencies and to lower the cost of the mechanical. Radiant in slab floors, HRV and HW drainage recovery are also part of the strategy. The heat loss calculation is approximately 20-25,000 btu's. I also have been looking at Triangle Tubes combination boiler and the combi tankless waters, but have hit the proverbial wall. Trying to make a decision that will not be over/under engineered, last, a simple install and have at a modest purchase price. Worried since our loads are so small the constant cycling on low fire will wear these units out and be expensive along with high maintenance possibilities. Am I on the right path or go back to the basics with a gas water storage tank/DHW and a separate small boiler for the hydronics???

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