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Mini split layout ideas for a 1928 Tudor/Colonial in New York

tbl01 | Posted in Mechanicals on

I started some research on trying to figure out the best layout, size etc, for a mini split system for my house. This was after getting some prices for central air and hi velocity systems, and the high tonnage they were specing, I decided to do so additional homework. This was primarily for cooling, but I do have an interest to use the heat on the front end and back end of the heating season which prevails in Westchester County, N.Y.

It is a 1928 Tudor/Colonial, based on my measurements its approx. 1300-1400 sq.ft. The house is 2×4 framing with stucco, with vinyl siding .

First floor 700 sq.ft Kitchen, living and dining, all connected with openings. Kitchen 30″ opening to living and dining. dining to living also has 60” opening. Living rm, connected to foyer/bathroom with door also stair to 2nd.Fl. Lots of windows. 3 per room( old double pane insulated 1980’s vintage) Kitchen, double pane older slider, and old large skylight, and new 2016 double pane High e kitchen window. R-11 walls .

2nd fl, 500-525- sq.ft, new remodel, R-15 walls, high-e windows, attention to air sealing, r-38 attic. 3 bedrooms, one bath, all connected by hallway, to short hallway down to first floor. Again lots of windows
2 bedrooms approx 150 sq. ft each, and one bedroom 85 sq.ft ,2 windows.

Based on calculator I used on line which was modified Manual J( which accounted for infiltration, insulation, doors, windows, exposure, I came up with about 28.8k sensible,and 2.4k latent for cooling.

After reading many articles and questions about the mini-splits, I am not sure how one could possibly do the heating and cooling with only a few splits given my parmeters.

For the first floor I was thinking, I have to do the kitchen, because if the amount of glass in the area , appliances and stove. It is always hot in the kitchen, 7k unit which would vent into both dining and living. One in the dining, which does not get used much, but if installed centered and opposite the opening,would vent directly into the living room.

I think the bedrooms need there own unit each, regardless, because of the door issue. 3 bedrooms, sometimes doors are open or closed, depends. Thinking could mount small room directly opposite door and could do hall/bathroom as well and other rooms would contribute to hallway and down stairs to living and foyer area is they larger then need to be.

I was looking at a 5 zone ([email protected]) system in particular a Panasonic 36k btu, or something similiar

Have attached sketch, and any ideas appreciated.

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  1. GBA Editor
    Martin Holladay | | #1

    You're on the right track. Upstairs, you could use two ducted minisplits -- one serving Bedroom #1 and the master bedroom (something in the ceiling of the closet between those two rooms), and one serving Bedroom #2 and the bathroom. These units would still be oversized for the load.

    Here at GBA, we're getting more and more questions like yours -- homeowners doing their own heat loss calculations and attempting to do their own HVAC system designs. The Achilles' heel of this approach is finding a contractor to install the equipment and stand behind the installation with support and warranty work.

    Ideally, you need to find an experienced contractor able to (a) size equipment, (b) install ductless and ducted minisplits, and (c) stand behind his or her work. If you can't find that contractor, these design exercises are somewhat futile.

  2. tbl01 | | #2

    Thank you for your reply Martin. Since my attic is very small, and since the celing is not a "conditioned " space, I felt the hit in efficiency with the ducts was not warranted. I am not sure exactly what you mean on the closet between the to rooms. Are you talking about leaving the closets doors open? The closet's are very small and I am not sure if they could be left open. But I need to investigate that area more closely.
    I do agree on the finding the right contractor who has the correct skill set to do the job. from sizing to install.
    I will keep you posted.

  3. GBA Editor
    Martin Holladay | | #3

    A ducted minisplit can be mounted to a ceiling (for example, a closet ceiling). Then a suspended ceiling or access panel is installed below the minisplit unit.

    If you use this approach -- installing a minisplit on the ceiling of a closet that is located between two bedrooms -- you can include two short supply ducts, one to each bedroom.

  4. tbl01 | | #4

    Got it. I just went up to the closets and took a look. I have a steep pitched roof which intrudes into one closet, but still might work in the both closets.

    Thank you. Oh more homework.; )

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