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  1. #1
    Join Date
    Nov 2012
    Location
    Charlotte, Michigan 48813
    Posts
    129

    Ductless Heat Pump as space heater?

    Thinking about a 3/4 to one ton inverter drive ductless unit in the living room, and using it to heat as much of the house as possible as if it were a wood stove. I like wood stoves, but with the cost of the chimney and fire insurance they can't really save me much money.

    From a search of old posts here, it looks like the good brands are Mitsubishi, Fujitsu, (and maybe LG if carefully grounded and surge protected)?

    As a recent thread mentions, the 3/4 ton units have higher SEER than the 1 ton units, and it looks like the Halcyon and Mr Slim don't show much more heat output for the 1 ton.

    I'm currently on a propane furnace at $2.20 a gallon with 95% AFUE. My electric rates are about 12.5 cents per kwh. Furnace duty cycle suggests that my design load is about 25,000 BTU at 0 degrees. Last summer I was able to keep the house livable on all but the hottest days with a 5,000 BTU window unit and fans. I put the first AC on high at dawn and turned on a second 5000 btu unit at noon, and it kept the house at 78 degrees on a 103 degree afternoon.

    It looks like I can meet all my AC needs and help out a bit on heating with any of the 20+ SEER Mitsubishi and Fujitsu 3/4 ton units (FE09/GE09 and 9RLF/9RLS). I never had an electric bill over 250 kwh last summer if that shows how little I use AC.



    Any comments/ideas?

    Since I care a lot more about heat than AC, should I ask the installer to place the wall unit lower than usual?

    Should I insist on best practices like surge protection, grounding the condenser to earth or a nitrogen pressure test, or just let him do his job his way and hope for the best?

  2. #2
    Join Date
    May 2008
    Location
    Central Fla.
    Posts
    311
    Don't have him lower the unit, factory requires a certain height for it to work properly,It says it will void the warranty if it is too low.

  3. #3
    Join Date
    May 2009
    Location
    Cummins, GA
    Posts
    1,559
    According to Mitsubishi, it is not recommended to install a M-Series AHU low on the wall. No mention of voiding warranty. See page 2 of the attached link.

    http://usa.mylinkdrive.com/uploads/d...nt/Install.pdf

    You would cancel out any savings due to longer run times because of improper air circulation. I just don't see the benefit. Install it high on the wall and let it operate as designed.

    As far as installation procedure. Pick a contractor you feel comfortable can do the job correctly. Ask any questions you need to. The only dumb question is the one not asked.

  4. #4
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,745
    I think this is a great idea for your needs. I would find a contractor you trust will do the job correctly and ask questions. There will be no brazing on a minisplit it will be flare connections so you don't have to worry about flowing nitro while brazing. I would make sure they do a proper pressure test once all is hooked up to ensure you don't have any possible refrigerant leaks, then make sure they pull a proper vacuum using a micron gauge. I like Mitsubishi and daikin personally but really they are all pretty much the same as long as you are comparing apples to apples with seer, eer, and hspf

  5. #5
    Join Date
    Nov 2006
    Location
    Athens, Ohio
    Posts
    2,070
    Check out the Mitsubishi Hyper-heat model. Much more heat output at low temperatures. It has 80% of its rated capacity at -13*F. I have one in my building and our customers love them.

  6. #6
    Join Date
    May 2008
    Location
    SouthEast
    Posts
    270
    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

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    Last edited by jpsmith1cm; 11-02-2012 at 11:44 PM. Reason: non AOP member

  7. #7
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,918
    jbeckham

    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

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  8. #8
    Join Date
    Nov 2012
    Location
    Charlotte, Michigan 48813
    Posts
    129
    Well, I did it, with the 3/4 ton 11 HSPF Fujitsu.
    Cost about $2.50 a day to run it. Hard to say how much propane it saved, but I'm guessing $3-4 a day.

    Temperature imbalances were worse than I expected, the kitchen felt cold all winter.
    Part of that is probably my fault for getting rid of the supply registers in the basement, which made the kitchen and bathroom floors colder but wouldn't affect the carpeted rooms as much. I'll definitely heat the basement from now on.

    I'd been thinking of getting rid of the Fujitsu and installing a central HP as a dual fuel with my propane furnace to get better distribution of the HP's output. My recent thread on Vision Pro aux heat staging reminded my why I went with the ductless last year.
    Looks like ducted would be more comfortable and ductless is cheaper, mostly because I can run the ductless with the furnace.

    One thing I hadn't planned on is that as the weather got warmer and the furnace ran less, the heat became more uneven and uncomfortable.

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