Before I grout my CMU walls, I want to sleeve them for a mini split line set. I’m not sure what unit I’m going to buy yet. Is 2 and a half inch enough (or considered standard) ... or should I sleeve for 3 inch instead?

  • I thought it was 3 inch inside diameter. . Jul 24, 2021 at 20:56
  • The sleeve depends on the size of the unit most of the ones I have installed have been 2-1/2” these have been 9k btu through 18k btu. There are larger ones that may require larger line sets it would be a very large room to need a 24k inside head unit.
    – Ed Beal
    Jul 25, 2021 at 6:04

1 Answer 1


I double checked the instillation instructions on several models up to 24000BTU single zone units 2.5” was listed as the hole size.

I was not sure if that was a standard size but 24000btu is large for a single zone and the brands I checked 9k through 24k 3 different line sizes including the self sealing were all 2.5” so it sounds like a standard size.

  • Perfect. I will have a 23,000 BTU max for 1300 so ft and sleeve according.
    – Michael M
    Jul 25, 2021 at 14:22
  • Sounds like I need 1 hole per zone?
    – Michael M
    Jul 25, 2021 at 14:25
  • 1
    Yes each inside unit has a line set drain and electrical that go to the outside unit.
    – Ed Beal
    Jul 25, 2021 at 14:42

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