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Community and Q&A

Cooling upstairs bedroom in misguided greenhouse

bmlabernethy | Posted in Mechanicals on

I built a house from 2013-2019 on some misguided principles from the 1970s-1980s and a bunch of old fine home buildings. It is well insulated with passive solar principals, lots of thermal mass insulated toward the interior and triple glazed windows, and tight enough that you have to push the doors closed unless a window is open (never did a blower test).  I was introduced to GBA after framing the house, but GBA is why I focused on air-sealing and why I bought a Daikin minisplit with a single head located in the lower earth-bermed floor of the house. It does a great job of heating the whole house, it keeps the summer humidity down (I live in central Virginia), and the lower floor stays 68-70 degrees, too cool in my opinion. When I built the house I erroneously installed 2 continuously flowing Panasonic 120 cfm fans in chases to circulate air from the bottom of the down stairs to the top of upstairs. They kinda work… if I just crack the upstairs master bed room door and pull the cellulose shade down on the only bedroom window it is cooler than the rest of the upstairs by a couple of degrees. Otherwise it is the same temperature as the rest of the upstairs which is 5-10 degrees warmer depending on the day and the days activities (how often the upstairs exterior door gets opened).
The problem is my wife HATES the heat. I find it comfortable enough to sleep in the worst situations when the dogs have pushed the door open and it is 80 degreeas long as the ceiling fan is blowing, she sleeps down stairs. She can sleep comfortably at 72 degrees but that is warm for her. So she has been uncomfortable for the last 3 months. During the day it isn’t an issue she is “ok” being warm while awake and we spend a lot of time downstairs. 
I am looking into a small 6K mini split for the upstairs, but would prefer a cheaper solution, especially if it is only needed at night for 3 months. Any suggestions outside of sleeping downstairs all summer?

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  1. MartinHolladay | | #1

    Q, "I am looking into a small 6K minisplit for the upstairs, but would prefer a cheaper solution."

    A. Install a window-mounted air conditioner in your bedroom. After running the air conditioner for a couple of hours, invite your wife to return to the bedroom.

    1. bmlabernethy | | #4

      We have casement windows...

  2. moe_wilensky | | #2

    What is the source of the excess heat upstairs? Is it stratification (i.e., heat gains throughout the house collecting at the higher level) or the glazing installed on that floor?

    1. bmlabernethy | | #8

      I believe it is the glazing up stairs, not from direct solar gain it has a properly sized awning and trees block east and western gains, but the lower R value the windows provide. All the thermal mass (for what it's worth) is down stairs as well.

  3. walta100 | | #3

    Have you found a way to shade your windows on the exterior in the summer IE trees\ awnings?

    Moving the bed down stairs does not cost much. LOL

    I like the idea of experimenting with a window unit for sizing the new mini split as 6k sound to small to my ear.


    1. Expert Member
      DCcontrarian | | #5

      Yeah, the interior shade probably isn't doing much good. Once the sunlight is through the glass a shade just dissipates it into the room.

  4. Expert Member
    DCcontrarian | | #6

    A 6k minisplit is like $700. How much cheaper are you looking?

    1. bmlabernethy | | #9

      I disagree, the shade make a noticeable difference.

      1. Expert Member
        DCcontrarian | | #10

        Who you gonna believe, the science or your own lying eyes?

  5. Expert Member
    Akos | | #7

    The inverter window units are much better than the old window shakers. I've used one of the Midea U shape units in a bunkie, cut a hole in the wall and slide it in. A piece of 2" rigid can fill the U notch and seal the rest with expanding foam tape.

    There are some companies out there that makes a pre-packaged mini split where the indoor unit is permanently connected to the outdoor unit (ie Forest Air). These are meant to be installed through a gap in a double hung window though. You can probably figure a way to get it through a casement and seal the gap.

    I think a DIY (ones with quick connect lines) mini split is probably your best bet though.

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