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I have a pretty large crawl space. It is 80 inches wide and around 7 feet high. I am looking to replace the 50 gallon electric water heater with the new Geo Spring Water heater by GE This unit is wide = 7 feet height = 5'5'' feet

As I understand, this Hybrid Water heater works by having a "reverse" A/C unit on top of it.

My Questions are:

  1. Is it advisable to put this water heater in the crawl space? Will it create moisture in the crawl space?
  2. Has any one used this water heater in their crawl space?
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Your climate is a key variable in answering this question. –  Bryce Mar 13 at 7:57
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2 Answers 2

You may be able to:

  • Height - The website says the heat pump water heater (HPWH) is 60.5 inches tall. The hot and cold pipes enter at the top of the unit, but it sounds like 7 ft is enough vertical space.
  • Volume - I'm not sure what the overall volume of your crawlspace is, but the GeoSpring installation Guide says:

With the installation of a louvered door, it can be installed in rooms smaller than 10' x 10' x 7' (700 cu.ft.). Louvers should be 240 square inches (0.15 m^2) or greater.

So, if your crawlspace is vented to the outside, or as HerrBag states, is conditioned, with air exchange to/from the house, it will be fine, but may operate at lower efficiency:

  • Temperature - Like you say, the water heater is a heat pump or "reverse AC", meaning it heats water by pumping heat from the air. In other words, it cools down the space it is in. If your crawlspace temperature gets below 45F because of the heat pump or just because it is cold outside, the unit will operate at a much lower efficiency. This study states that HPWHs take 10-15% efficiency penalty when installed in confined spaces.

  • Humidity - High humidity is not a problem. In fact, it will operate more efficiently at higher humidity. Freezing temperatures are an issue for efficiency, as stated above, as well as the obvious danger to your pipes. As HerrBag stated, a floor drain or pump/sump will be necessary.

What climate are you in? If you are in a hot climate, it is advantageous to put the heat pump water heater in your living space to take advantage of the free cooling.

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One thing to add with the humidity - not only will the HPWH not create moisture in the space, it will actually reduce it (assuming correctly drained condensate). –  Zhentar Jul 11 at 18:32
    
@Zhentar Actually since all the HPWHs on the market have relatively high sensible heat ratios (> 0.80), they will decrease the absolute humidity in the space, but increase the relative humidity (since they also reduce the dry bulb temperature). Probably not a big deal, but they can't be counted on as a dehumidifier (unless you are simultaneously heating the space). –  littleturtle Jul 12 at 20:24
    
That's true, although since lowering the absolute humidity lowers the dew point, it still improves one of the major crawl space concerns. As for heating, if the floor above the crawl space is insulated well enough that the house doesn't heat things back up, once the air temperature drops below the ground temperature, the earth will heat it back up for you. –  Zhentar Jul 17 at 15:49
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I would get approval in writing from GE for this install, as it sounds like the destination is not compliant with some of the technical requirements

  1. Room area > 100sf. You at ~ 40.
  2. Air supply to area. I don't know why an electric heater needs air like a gas unit would, but it's in there.
  3. Floor drain for condensate (or a pump)
  4. Bad environmental: high humidity and potential freezing(?)

If you were to bring the crawlspace "into" the conditioned envelope of the house(seal floor with vapor barrier, insulate, air exchange), you might satisfy GE.

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