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Community and Q&A

Heat pump condensers in crawlspace?

margie_lynch | Posted in Mechanicals on

I’m installing two one-ton Mitsubishi Hyper Heat minisplit condensers in my new 960 sq. ft. modular home in Jackson, Wyoming. It’s climate zone 7 (10,000 heating degree days, code design temp is -30 degrees F) and there’s lots of snow, so I asked the install crew to build a shelter on the side of my home to protect the outdoor units. The HVAC contractor is scheduled to install the condensers later this week and has just suggested that the condensers could be installed in my crawlspace (960 sq. ft., 5 ft. high). I’ve never heard of such a thing and I certainly don’t care about the aesthetics.

The one article I found on this here suggesting “no way” is over ten years old, so I thought I would poll this knowledgeable group to gather your thoughts, especially given the cold conditions. My instinct is no, but I’d like a more reasoned basis.

Thanks, all!
Margie

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Replies

  1. Expert Member
    BILL WICHERS | | #1

    I doubt that's going to work. When running the unit for heating, the outside units are scrounging heat, which means they will "blow cold" -- like air conditioners. The heat is getting pumped INTO your house, instead of pumping heat outside the way an air conditioner would.

    If you scavenge heat from the crawlspace, you'll cool that off and essentially "suck out" heat from the home. That won't really work when you're trying to heat the home. I doubt the heat from the ground would be enough to offset the heat removed by the heat pump to heat the home, meaning that the temperature in the crawl space will drop.

    I would not advise trying to install the condenser units in the crawlspace here.

    Bill

  2. user-5946022 | | #2

    What type of crawlspace do you have?
    a. Completely open to the exterior (ie house on piers) with the underside of the floor framing system completely sealed?
    b. Traditional crawl space with perimeter foundation and unconditioned crawl space with vents?
    c. Sealed semi conditioned crawlspace?

    If a, it might work, but there is usually a minimum free area above the unit, and a 5' height sounds insufficient.
    If b, seriously consider changing to c.
    If c, this won't work - it is like putting the outdoor unit inside.

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