Plumbing and installing a ductless minisplit on the 2nd floor of a new build is more challenging than a 1st floor install. How far can one run the refrigerant lines from the wall mounted unit to the exterior compressor unit? Are there any issues with running them up to the 2nd floor when the exterior compressor unit is all the way down on the main level?

I would prefer to install a ductless minisplit on the 2nd floor rather than a ducted unit. The 1st floor has 2 ductless mini's but the 2nd floor is posing more of a challenge.

The install manual for each model should be quite detailed about the distances and height limits for mounting the units apart from each other, but going between floors is not a problem.

ETA: Document the locations of the linesets very carefully, using photos and reference points.  Future subs are not accustomed to finding such things in the walls.

Posted By ICFHybrid on 18 Jan 2014 07:42 PM
The install manual for each model should be quite detailed about the distances and height limits for mounting the units apart from each other, but going between floors is not a problem.

ETA: Document the locations of the linesets very carefully, using photos and reference points.  Future subs are not accustomed to finding such things in the walls.

I plan on burying the lines within the exterior wall by taking out the ICF EPS foam and then foaming over them and stucco. My other question is how wide are the exterior lines? Can one place them beneath the 2.5" of EPS foam in the ICF, foam it over, then stucco?

The exposed retrofit lines I sometimes see (white vinyl) is not aesthetically appealing. It can get gaudy looking.

Each line is up to two inches (+/-) with insulation. They will go fine in the foam.

I really like the idea of having only 3-4 ductless minisplits cool/heat the entire home (2 on 1st floor and 1or2 on 2nd floor) instead of having ductwork on the 2nd floor. The house design is very open and after reading the GBA articles, I can live with a 4 degree temp difference in some rooms.

Although the duct work on the 2nd floor would be very minimal/short runs but ducts are never as efficient as ductless minis. The elimination of an air handler also saves me some money as does not having to install ducts in the ceiling. I'm reviewing the design but it's going to be tricky to get the 2nd floor to have minis installed because running that exterior line to the compressor will not be a straight and easy run.

Can the mini wall unit line run UP into the attic or must the line go out and down immediately?

IIRC, mine go up and down and all around.

If you have an open plan on the second floor, you might need some way to move the warm air out of there, or your second floor units will be working too hard during cooling periods.