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Community and Q&A

Heat-Pump Water Heater Recommendation

Gwisejr | Posted in Green Products and Materials on

The Nyle Geyser C-8 has been delayed another 6 months the last time I checked in Dec. Does anyone know of another device that is similar to this unit that is available in the US?


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  1. GBA Editor
    Kiley Jacques | | #1

    I’m giving your question a bump. While you wait for readers with recommendations to weigh in, take a look at this Product Guide post: Choosing Among the Most Efficient Water Heaters. A number of products are discussed and there are lots of related resources I think will be helpful to your search.

  2. user-2310254 | | #2

    Sanden ( is often recommended.

  3. Gwisejr | | #3

    I was looking at that. My issue is that 1 would like a water tank in the 50Gal range but I want to place it in my crawlspace which has a concrete rat slab and the max height is about 32" to the floor joists and about 46" to the bottom of 1st floor with a 23" joist spacing. I've not really been successful at finding a ~32" lowboy solar/indirect water tank in that 50 gal range.
    Also, looking at the Sanden unit, seems like it does not operate the Tank to Compressor loop as a closed loop system with a heat exchanger pipe in the tank. I get the impression that circulates the water supply to the compressor. I'd rather have a closed loop system as I am on well water. I do have a filter set up but I'd rather have that closed looped. Lastly, I can setup for a 240v compressor unit but I'd rather a 120v unit if possible. I'm on solar and I plan on moving my existing 50gal electric over to the smart load breaker on my Sol-Ark inverter and use that as a water pre-heater when I have excess generation.

    Can anyone confirm if that sanden unit is closed looped or not?


    1. GeneDJ | | #4

      The SanCO2 water heater has a heat exchanger in the outdoor unit and circulates potable water from the tank to the outdoor unit to be heated. The outdoor unit is a monoblock heat pump; the whole refrigeration system is in the outdoor unit. Not many techs can work with the CO2 refrigerant so it is best that it is self-contained. So if the refrigerant loop were extended indoors to the tank it would be more vulnerable to leaks. Also the thank must be vertical for stratification, so it sounds like it would not work in your crawl space. I think most manufacturers want a vertical tank, but contact Nyle and see what they say about their packaged E8 with separated tank.

  4. Expert Member
    PETER G ENGLE PE | | #5

    Is there a possibility of taking the floor out of a closet and standing the tank up through the floor? Won't take much closet space and gives you the option of a vertical tank.

    1. GeneDJ | | #6

      Or just leave the closet as is and put the tank in there. Another thing you should know about the SanCO2 water heater is the freeze issue. With water circulating to the outdoor unit it must be dealt with. They have developed several strategies to do that and I don't recall them all. Just running the circ pump will prevent freezing down to very low temps. But they monitor the water temp and have auto-drain valves if power fails entirely.

  5. Smith2022 | | #7

    NYLE now has an availability date of August 2022 for their E8 (updated Geyser) and apparently it will only be available for licensed installers

    1. user-5946022 | | #8

      Is the E8 a viable option for residential hot water supply?
      Nyle's product data ( indicates it's recovery rate is 10 gph, which seems low. Even the Rheem 110 HPWH has a recovery rate of 16 gph...

      1. Sevillehermit | | #9

        I contacted nyles and the e8 is intended to be used to complement an existing water heater.

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