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Tankless water heater for greenhouse

Discussion in 'Growing Areas' started by YEAHYEAH, Jul 10, 2012.

  1. YEAHYEAH

    YEAHYEAH Member

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    Hello all, looking to install a tankless water heater in the greenhouse to just knock the chill off the water in winter. Water would most likely be around 40 F most of the time in the winter mornings. Not worrying about hot water for any other purpose. Any ideas, sizing, or maybe the ones with a small 7 gal. tank. I would most likely run 3 to 4 hundred gal. max. during a heavy watering day.

    I live in Northern California

    Thanks, Adam
     
  2. msaar

    msaar Member

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    Location:
    Little Rock, AR
    I've had a tankless water heater in my GH for about 14 years (Bosch). No problems, I recommend it to everyone. An electric point-of-of-use heater would probably be too small. The obvious beauty of the tankless heater is that it only uses fuel during watering. For me, it also provides emergency back-up heating in case of power outage (it has a standing pilot and requires no electricity) In case of electricity or heater failure, I can use fully heated water sprayed through a few Fogg-IT nozzles to keep things warmish. I blend hot and cold water using a Powers mixing valve (like a shower valve).
     
  3. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Location:
    Santa Rosa, CA
    When I could still use city water I heated it in the winter for watering. Since I switched to RO I haven't been and I miss it. I've been considering an electric on demand water heater. Since I would be using only a small amount of hot water to temper the cold water in my holding tanks it seems that it isn't going to be heavy demand. I'm interested in your comment that you think it would probably be too small.
     
  4. msaar

    msaar Member

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    Location:
    Little Rock, AR
    The electric point-of-use heater I was talking about (and I believe YEAHYEAH was talking about) is a small conventional tank-type heater with a 6 gallon tank. With 40 F. water, and a final use temp. of say 60 F, you would use 1 gallon of hot water (these are unlikely to produce above 120 F water) for every 3 gallons of cold water, producing 24 gallons of tempered water. There are electric tankless point-of-use heaters; the smallest produces .5 gpm w/ 57 F input water. If you do the math, I believe you will find that you will need a 240 V. heater to provide an adequate heater. These small heaters are designed to provide hot water for one bathroom sink, and flow will be an issue for greenhouse watering.
     
  5. Uluwehi

    Uluwehi angraecoids, dendrobiums and more Supporting Member

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    This is an interesting discussion that gives me some options to ponder.

    Before long I would also like to heat my RO storage tank, ideally just early enough before watering time, instead of heating 24/7.