Fingers crossed!

You are correct the material is on inside filter and installed on top. Since it is attached to velcro dots the seal is not complete but does catch a lot of dust.

@Gerald Bought some of that blue filter material. It says to install "with blue facing outwards" but I'm thinking, shouldn't it be facing the unit as we are really wanting the air entering the minisplit on the top to be clean (rather than as would be typical for are leaving)?

1 hour ago, BB1 said:

@Gerald Bought some of that blue filter material. It says to install "with blue facing outwards" but I'm thinking, shouldn't it be facing the unit as we are really wanting the air entering the minisplit on the top to be clean (rather than as would be typical for are leaving)?

I installed with blue out. In my opinion it should not matter in this case. With frame filters the reason for directional flow is due to the structure of the frame. 

@GeraldAfter looking more, I think it should be blue side out like you have it. Took me a bit as the product info had me confused. The blue side seems a bit more course so makes sense it would be the first to filter incoming air. 

Edited January 22Jan 22 by BB1

After many bumps in the installation journey, the minisplit is in place and running. Have to work on the "pre-clean" filter setup, but thankful to be at this point. Really warmed up the shop area. Will be so nice to be able to work out there when the weather turns cold outside.

52 minutes ago, BB1 said:

Will be so nice to be able to work out there when the weather turns cold outside

And equally as nice when it turns hot and humid. Great that everything finally came together especially before this winter storm front arrives.

23 minutes ago, Grandpadave52 said:

And equally as nice when it turns hot and humid.

Yes, I've been driven out of the shop equally by heat. Sweating all over my tools is no good!

A long journey, but worth it! Congrats!

Worked on pre-filter setup. Almost done. Went with horizontal 4 inch filters on a ledge with an enclosed gap below to the top of the minisplit thanks to a door that goes from above the filters to just below the top of the minisplit door.

Still need to get a latch for the door so the foam will "seal" things up.

Hopefully will keep dust out without impacting the air flow. Unfortunately, there was an issue with the filters I was sent so company is sending new ones after reviewing the pictures I sent.

Relieved to at least be this far. Much thanks to my husband for brainstorming the design with me, doing the painting, and helping lift and install.

Excellent Barbara. Looks really good with ease of serviceability.

11 minutes ago, Grandpadave52 said:

Looks really good with ease of serviceability.

Way too much mental deliberations went into this, but looks like it should work. The cost of the minisplit is a big investment so trying to ensure the unit stays clean and that we can easily check the internal screens.

Design looks very serviceable. Gives me an idea to do box with filters at top and maybe front also. Thinking 12 x 24 filters as that is what the air cleaners use.

Edited February 10Feb 10 by Gerald

44 minutes ago, Gerald said:

Thinking 12 x 24 filters as that is what the air cleaners use.

Would be nice to have one 12x40 filter as that would have spanned the entire top, but couldn't find that particular size. We are still trying to figure out the "sealing" aspect across the front/sides of the door. The foam needs to be recut as I'm not satisfied with how I cut/trimmed to go with the MS door profile (would be easier if it was totally flat!). Figuring out a latch is also needed.

A suggestion. You could make a filter housing, using chicken wire for support then just replace the media. Just be a frame with wire and media.

A caution to consider: in-room cassette air handlers are usually not designed to overcome external filter pressure drop. Adding filters to the fan duty might significantly reduce air flow and performance; IOW, it produces less Btu cooling/heating, AND the air doesn't penetrate into the space. The filter usually used in such units is OK with normal residential air particles (mostly human skin flakes and hairs, fairly large diameter, 100 micron or so, easy to capture), but won't take out the fine dust (2~10 micron) you should worry about. While it would violate the code of ethics of DIY, getting a room filter unit with substantial filtration, and blowing that clean air into the AC cassette, is a better strategy.

5 hours ago, PeteM said:

A caution to consider: in-room cassette air handlers are usually not designed to overcome external filter pressure drop

Yes, definitely a consideration. We are watching the air flow, and used a 4 inch filter, plus the air gap, to try to address that. Will monitor as we start to use it.

Edited February 10Feb 10 by BB1