I’m thinking about a mini split AC for the barn workshop. The only potential problem is wood dust. When I’m woodworking, which is about to fire up again soon, wood dust gets generated. I have a large loud ceiling mounted air filtration unit, but it doesn’t get all the dust, and the window unit AC catches the rest. I can wash the AC filter, but the filter doesn’t stop all the very fine dust. It deposits on the fins. I have to clean the fins as well as I can.

I’m ready to move up to better cooling. The window unit is the third I’ve had in that window, and I'm tired of replacing them. Having a mini split would bring better cooling, but the dust problem remains.

So, finally, the question that matters. Can I get a mini split with air filtration to catch most of the dust, fines included? Are the filters easy to replace or clean, and are they HEPA quality? It’s not an AC problem, but more of a dust control problem.

Any real knowledge you can share will be appreciated.

Real knowledge is mini splits only have a screen for a filter. Wood dust gets all over the coils. The air inlet and filter is on top. I’ve considered building a box on top of mine that will house and additional filter system. Something easy that will fit standard 20x20 filters. I was thinking if it held at least two of them it would be a problem solver. Cheap and easy to construct, even more so with you woodworking knowledge.

The guy who sells hundreds of them a year here told me they are not designed to be in a dusty environment. I was thinking the same thing about my shop where I make knives and decided to stick with giant window units.

I think you could do something like this and it would work. And my 4 ton Lennox split made my shop great. I got dual heads in 1200 foot shop with 16’ walls and I can make it 68 degrees in there if I want to. I leave it on 80 though and it feels great with the bigass fan on.

Well, it’s cheaper if I put in a big new window unit. I suppose I could just get another one. Hopefully a better one than the present one. I get about 3 years out of them, and was hoping for better AC performance than from this one. I think it’s an LG. These big ones are heavy, and my weight lifter neighbor is down for the count till September (serious neck surgery). Oh well! Ain’t a big deal…

Don’t forget the mini-split is also a heat pump and a whole lot more efficient than a window unit. Also has a dehumidifier setting. It’s not just a window unit with a different shape.

Mine has screens. I just have to remember to vacuum them off daily when woodworking.

They make heat pump window units as well. I dealt with this on my sons show chicken house has well. Every person I asked in the hvac business said minisplits don’t do well in dusty environments. On the other hand it clogged up the window unit also.

I put a mini split in my new reloading area. It works great, but I can see where a dusty environment would be tough on them. That filtered shroud mentioned above may work.

I once had that issue. I got a screen door and put it about a foot from the AC unit. It didn’t catch it all but definitely helped.

I have been making my own filters for years for a few odd sized remote returns in the house, as well as the shop window unit, using quilt batting. The wrapper says Poly-fil Low Loft small. I just cut the stuff to fit. The product I've found at Walmart has varied in thickness. I've even doubled layered it before. Since they are pretty nasty when I change them, and my coils stay clean, I guess it works pretty well. On the shop unit I put it over the screen filter.

I have a mini split in my knife shop and it works great! I also have a big dust collector that vents the majority of my grinding dust outside into a water bucket

I have a real good AC guy. I’ll talk to him and see what he suggests about which unit to use and what he thinks about dust collection. I can get a new window unit for $400 or so, and having it need to be replaced isn’t so painful. An expensive mini split though needs to be kept functional so I wouldn't have to swap it out for serious bucks. Need to make a well thought out decision.

I would get a 220V window heat and AC. I think GE makes a 24,000 or so BTU one. About 600 bucks after tax.

It’d cost me to run the 220 to where I’d need it.

For the record, I am not an AC guy but have dealt with a few in my lifetime....

With that said, I would ask your AC guy if it is possible to build a return plenum with a better filter. The return and the plenum and filter would need to be sized so it doesn't restrict the air flow but I don't see why this wouldn't be a possible solution.

They do have ducted mini-splits that might help with location to avoid most of the dust you are creating.

The splits are more efficient than the window units but like you said, they cost more too. Only you can decide if it is worth the additional cost.