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  1. #1
    Join Date
    Dec 2006
    Posts
    82

    mini-split in WI?

    Haven't posted here in a while... How's everybody doing?

    Here's my situation. The breezeway between the house and the garage was converted into a den back in the 60's. The 120 sq foot room has wood floors over a slab. There is almost no way to get ductwork to this room. Primary heat is therefore provided by two electric baseboard heaters together using about 2750 watts @ 240v to produce about 9000 btus of heat. These run constantly during the WI winter producing shockingly high electric bills during Dec - Feb while struggling to keep this room at 69 degrees F. Here in Milwaukee during those months, temps are generally in the 0 - 20 degree F range with averages in the teens. During the summer, the AC runs pretty well to cool the entire house. It starts up around noon and runs more or less constantly during hot days to keep the house at 74 degrees. When temps exceed 90 degrees (very rarely), the AC can't quite keep up and temps slowly increase to a high of about 78ish. I'm thinking the AC unit is sized almost perfectly for the house/den combination but could benefit from the YMGI during those few hot summer days where the temps soar above 90 degrees.

    Based on all of this, I'm thinking of having my HVAC guy install a mini-split for the Den. Specifically, I'm considering the YMGI WMMS-09K-V2A. This seer 22 mini-split produces a maximum 11,100 BTUs while using 1,100 watts at 120v. It is claimed that the working heat side ambient temps for this inverter powered gizmo are 5 degrees F to 86 degrees F. I've attached YMGI's spec sheet for the device.

    So, what do you guys think about this crazy scheme?
    Attached Images Attached Images

  2. #2
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,660
    So what's the big deal? It's pretty much what these things were designed for and used for most often.
    I like DIY'ers. They pay better to fix.

  3. #3
    Join Date
    Dec 2006
    Posts
    82
    I pretty much thought the same but I'm wondering about efficiency at the lowest temps since I'm on the northern edge of the climate reigon that this type of device is spec'ed for. I also wanted to verify that I will be saving money over the long haul. I'm pretty sure the unit is sized correctly but I'll defer to my HVAC guy for the final say there. Are there other options I haven't thought of? Does anyone have experience with the reliability of YMGI high efficiency devices (or SANYO compressors)?

  4. #4
    Join Date
    Oct 2009
    Location
    Florida
    Posts
    169
    For a room that small I would look first at sealing and insulating it to reduce your heat losses. 9k btus should be able to keep a 120 sqft room comfortable. Also, though I've never worked on YMGI equipment I do know the sanyo dc compressors are very good quality.

  5. #5
    Join Date
    Dec 2006
    Posts
    82
    yup. The room definitely needs a new picture window, new sliding doors and an additional layer of insulation in the attic. I know I have to do all of these but am trying to get the best bang for my buck. The plan was to do the attic insulation and the mini-split before the 2011 heating season fires up then analyze energy bills and decide whether or not to do the window/sliding doors (big bucks) based on that.

  6. #6
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,660
    I'm not sure a 120 sq. ft. room with a 9k btu mini split is going to affect your electric bill dramatically with or without new doors/windows honestly.
    I like DIY'ers. They pay better to fix.

  7. #7
    Join Date
    Dec 2006
    Posts
    82
    Bummer, I was thinking the mini split could save $30-$60/month over the baseboards simply by virtue of the fact that it uses 1.65KWH less to do the same thing. Maybe I should just concentrate on insulation in the walls/attic this year.

  8. #8
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,660
    What is your total electric bill for your entire house? You have to keep in mind that your heating and cooling is just a certain percentage of your electric bill. This room is a percentage of that percentage. Insulation and weatherizing yields a whole lot more bang for your buck than putting a shiny new box on your wall or in your attic.
    I like DIY'ers. They pay better to fix.

  9. #9
    Join Date
    Dec 2006
    Posts
    82
    Well, last January my electric bill was $389.20. The house is mostly LED lighting. Other electric items include high efficiency water heater/washer, server farm/computer room that draws $60/month (measured constantly with a kill-a-watt). The furnace is a 10yo Heil 80% single stage which uses an unknown amount of electricity to run the blower.

    At .13/KWH, the baseboards cost me .36/hour or about $3.60/day given the fact that they don't run during the night. That approaches $110ish per month during the coldest months. The house is pretty much open to the Den with a large double opening to the living room and a single opening to the kitchen.

    The wife told me that 120 sq ft was crazy for the Den so we just measured. She's right (she always right and if she isn't I just smile & wave...), it's 11' 8" x 18' 6" so about 216 square feet.

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