Tankless Water Heaters

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Tankless Water Heaters

Post by TxRobNLA » Tue Oct 28, 2014 9:47 am

Has anyone had to deal with having to heat your water in the greenhouse and gone with a tankless water heater?

I lost a number of plants this last year because our water got too cold during the winter. Not going through that again this year. I had debated adding a holding tank under the benches in the greenhouse that could regulate the water to the greenhouse temp and then I would be able to also produce some RO water to improve the quality of my water. But that is going to be expensive and a large amount of hassle.

A tankless water heater would solve the short term problem, would be cheaper and easier to implement overall.


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Re: Tankless Water Heaters

Post by peterlin » Tue Oct 28, 2014 10:41 am

Hi Rob,
I have a tank less water heater for my greenhouse. It uses natural gas so I get endless supply of hot water. The heater itself is located in my storage shed - 10 feet away from my greenhouse. I had a valve installed so that it automatically mix cold and hot water together. I don't need very hot water to water my plants, thus I thought warm water is good enough.

The problem I encounter is that cold water has to flow at a large volume for the tankless water heater to kick in. If I just water a small amount of water, then water heater will not turn on. Because I grow most of my plants in moss - I don't want the full blast of water to get them very wet in the winter. I prefer to dispense a small amount of water enough just to wet the top layer of moss.

So I have a holding tank of 40 gallon that holds RO water. I use a circulating pump and 400 watt aquarium heater to keep the water at 70F. Then I use delivery pump to water my plants. The trouble is I need a 80 feet water hose. It is clumsy to drag a long hose from one end of the greenhouse (water holding tank is located) to another. I tried quick connect before - as there is a 25 feet water hose under each bench. But quick connect is not so easy to mess with day to day - so I'm now back to using 80 feet water hose.

40 gallon holding tank isn't much. But if I run out of RO water, I can fill it up with tap water from tankless water heater. I hope this makes sense.

Peter Lin, Admin
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Re: Tankless Water Heaters

Post by raybark » Wed Oct 29, 2014 4:46 am

I had considered one at one time, but they are fairly pricey, and as Peter said, they are designed to provide hot water, not warm.

I went with a simpler route and bought a large wattage aquarium heater and put it in the RO tank. I set it at 75°, and everyone in the greenhouse is much happier.
Ray Barkalow, Orchid Iconoclast
Using science & logic to improve orchid growing

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