Replies

1. 
   brp_nh | Nov 12, 2022 08:37am | #1

   Yes: https://www.greenbuildingadvisor.com/article/siding-and-interior-finish-work-in-new-hampshire

   CZ 6, New Hampshire, 2 story 24x32' house, "Pretty Good House" concept, interior doors are usually open (no kids). The interior head (12k BTU Mitsubishi) is located in the open concept downstairs, outdoor unit is hung on north wall.

   It has worked out fairly well. In winter, the heat rises, but the upstairs is often a couple/few degrees cooler. When running AC, it does a great job dehumidifying the whole house, but upstairs can be a few degrees warmer.

   Do differently? Maybe bump up to the 15k size if still going with one minisplit. I'd mount the exterior unit on the ground and not the wall, for fairly minor noise/vibration issues. I could also see upgrading in the future to a 2 zone system with single 24k outdoor unit with 2 interior units (12k and 9k, or 15k and 6k), but it's not necessary right now or worth the cost since the 8+ year old install is still working great.

2. 
   boxfactory | Nov 12, 2022 11:36am | #2

   That’s great info. Beautiful house BTW. If after 8 years you can’t really think of much besides mounting the outdoor unit on the ground, then that says a lot. Hopefully I’ll be in your neck of the woods soon for some skiing.

   Thanks again,
   Ben

3. 
   kyle_r | Nov 12, 2022 01:09pm | #3

   I live in Michigan (Zone 5) and have a 15kBTU/hr Fujitsu floor mount on the open concept first floor and a 12kBTU/hr ducted Fujitsu upstairs for the bedrooms. Each floor is 1200 sqft. The first floor unit heats the entire house, with the second floor a few degrees cooler. I use the second floor ducted unit for A/C.

   If your house is fairly well air sealed, one unit can work for heat especially since most people are ok with cooler bedrooms. I think whether one unit is adequate will depend more on your needs for A/C.

4. 
   boxfactory | Nov 12, 2022 07:42pm | #4

   Very reassuring to hear your experience. We will probably go with less AC use anyway, as we hope to mount ceiling fans in the bedrooms.

   Thanks!
   Ben

5. Expert Member
   Akos | Nov 12, 2022 09:17pm | #5

   In a new build with good air sealing, you will need ducting for fresh air. To use that same ducting also for heat and cooling means bumping up the duct size by about 1", so essentially zero extra cost. This gets you even heat distribution through the whole house and cooling in all the rooms with the doors closed.

   A bonus is that most slim ducted units or multi position air handlers can take a proper air filter, so you get better filtering plus less maintaince down the road. Having done it a couple of times, cleaning wall mount coils and blower wheels is not fun.

   Comfort is one of the biggest improvements you can make when building from scratch, for a any new build, I would not go with a wall/floor/ceiling mount.

1. 
   kyle_r | Nov 13, 2022 09:18am | #7

   I agree with Akos 100%. While I made a ductless mini split work on my first floor in a retrofit, I would definitely log with a ducted unit in a new build or major rennovation.

6. 
   boxfactory | Nov 13, 2022 08:21am | #6

   Thank you! I’ll be sure to keep in mind future maintenance, and try and build with that in mind.

   Ben