So You Want to Install a Ceiling Cassette
Can you do it? What should you consider?
Wow. Ceiling cassettes look so nice. Everyone should get one, right? Who needs those mini-splits on the wall when you can have one of these?
Well, turns out there are a few requirements. And they come with tradeoffs. This article talks about them.
What You’ll Need
A spacious attic, or ideally some empty space above the ceiling cassette
Joists that are greater than 14 inches apart
Ceiling material that is preferably easy to cut through
A healthy appetite for debris, b/c we’re cutting a huge hole in the ceiling
Willingness to pay more, because it’s more work than a simple wall unit
The Basics: How Do They Work?
You cut a hole in the ceiling & you hang the unit between the joists. Like this:
& then you put a cover on it.
Here’s how that looks from the attic:
You can see that the unit itself is actually suspended by suspension rods. This is how that looks like:
You’ll need those suspension rods to go on first, before lifting the unit up & suspending it:
So, it’s a two-person operation.
Now, the suspension rods can be bolted up to the rafters, or suspended on a beam like the photo above. Here’s one suspended from rafters:
But I’ve also seen in the past some more.. creative ways to do it:
In that case, this was underneath floorboards in an attic that eventually was converted from an unfinished space to a finished space. I think personally I wouldn’t recommend this unless you have an access panel of some kind that makes it easy to connect/replace refrigerant or condensate line connections, but from a technical standpoint, it is possible to install it like that. It just comes with tradeoffs.
How Big is this Thing?
This is the smallest model out there: the MLZ-KX06NL. It’ll fit if you have 14 inches between your joists.
Critically, the ceiling hole opening:
Mitsubishi has the smallest unit, Daikin’s one-way ceiling cassette hasn’t come out yet, and LG has a cassette as well. Both Mitsubishi & LG’s should have wifi out of the box right now, so that makes life easier.
Here’s the slightly bigger 9k BTU variation:
Ceiling Clearance
This thing is supposed to hang between your joists. So your joists need to be big enough to fit them.
<14 inches: probably too small
~14 to 16 inches: perfect, there’s a chance you can suspend cassette via. joists themselves without suspension rods
16 inches+ (or otherwise, much larger than the stated size of cassette width): suspension rods required
Ceiling Material
If it’s horsehair plaster, it becomes super annoying. It’s also super annoying if you have wire mesh like this:
It goes without saying that it creates more debris, and your crew will need PPE.
Spacing
Remember what I said about how it’s a 2-person job? Yeah, so it’s way easier if you have either someone in the attic, or enough space in a side panel where someone can get on a ladder next to a unit & screw the suspension while someone else is holding up the cassette itself:
Again, the previous photo of an LG ceiling cassette:
Final Steps
That’s how it looks without a cover. Once you’ve suspended the unit, and completed the work, you’ll put this cover on it:
Okay, that’s it. So, long story short, since we like to ensure there’s proper service clearance, we typically are willing to do ceiling cassettes right below unfinished attics with the right amount of space between the joists. (Preferably in the shoulder seasons - it’s super hot in attics during the summer!).
Techs out there - if you have thoughts, let me know what you think!