My shop upgrade is going to be installed later this week - a minisplit (insert celebration here 🥳). Looking forward to temperatures that allow me to work year around with no "so cold I cannot work safely" or "I'm sweating so much in my dust mask."

 

Obviously dust is a definite in a woodworking shop. I'm researching options to filter the intake air to avoid issues with dust in the unit. 

 

I saw this video on a filter system for above his minisplit. This is his follow-up a few years later. This guy with similar setup suggested lower MERV filter. 

 

Interested in experiences others have had with keeping a minisplit clean in the shop.

 

Thanks!

 

I have a Mini Split in my new shop (September) by Daiken which was highly recommended. I think the first video is way overkill. My installer said I could lay filter material on top of the unit. This   Is actually filter material which you can cut to size and comes with velcro dots to attach. It comes n several sizes and one filter is enough to make two for my unit. I placed it on top and in the front to cover system filters. Seems to work well. I have cleaned it twice.  

 

Well this software will not let me post Amazon link. I searched first for motorcycle filter material but came on this cutable air filter which fit the bill.

https://www.amazon.com/dp/B0F9487CGS/?coliid=I2Y4KGHI5AB7K3&colid=GPQ5RMQM7YI&ref_=list_c_wl_lv_ov_lig_dp_it&th=1

Try highlight copy and paste. this is the description. Air Vent Filter, 18"X90" Cut to Size MERV 8 Triple Air Filter Material, Blue & White Electrostatic Vent Filter Kit for Home Floor, Ceiling, Grilles, HVAC Vent, Compression Packing

Edited January 8Jan 8 by Gerald

Gerald - thank you so much for this! I think this is the product. Definitely looks to be much simpler. Have you noted any concerns with air flow limitations? When you say you have cleaned it twice -assume you mean the minisplit. Do these filters just get replaced?

[Been doing this since '72]  Air filtration is a balancing act between particle capture (volume and individual particle size) and air flow.  Filtration doesn't really PREVENT dust penetration, it just lowers the rate of penetration (ie, sooner or later the dust wins...but might be years).  MERV 8 would be a minimum for capture.  MERV 13 would be a probable maximum for ordinary units, but if the fan wasn't sized for the extra drag of M13, you could reduce the thermal output (and in extremes, harm the unit).  A key test is the supply air temperature (the air coming out the grille):  these units are generally designed for a "20 degree split":  measure entering air temperature, subtract leaving air temperature on a hot day, and conditions such as 80/60 or 75/55 indicate pretty close design air flow.  If you measure something like 80/50 (or in the 40's), you're probably restricting the  air flow too much.  Temperature "split" is also subject to outdoor conditions (with air cooled units, which is most of them):  the hotter the outside air, the lower the split value.  But in general splits of 18~22 are OK.

1 hour ago, PeteM said:

  A key test is the supply air temperature (the air coming out the grille): 

Thank you for that info. Is there any other way to measure this? Not totally understanding how to take these temps.

11 hours ago, BB1 said:

 My shop upgrade is going to be installed later this week - a minisplit (insert celebration here 🥳).

Congrats Barbara on the up-coming addition; green with envy.

Remember the second law of the land here; pictures or it never happened.😉

I donut need to remind you about the first law of the land here; donut forget the celebratory doughnuts.

48 minutes ago, BB1 said:

Thank you for that info. Is there any other way to measure this? Not totally understanding how to take these temps.

Almost any thermometer will do (if graduated for the span of 40~100 F ).  Just hold it in the rough middle of either the air intake or discharge, moving it around a little to get a good average.  The intake air should be the same as the room temperature.  You have to hold it in the air stream long enough for the temp reading to stabilize, which means you have to keep the compressor running while doing the measurement.  Using temperature is more reliable than trying to measure air flow directly.  Air measurement is +/-25% on a good day, even when you know how to do it.

1 hour ago, PeteM said:

Using temperature is more reliable than trying to measure air flow directly.  Air measurement is +/-25% on a good day, even when you know how to do it.

Thanks for that added info. Chuckled at the "even when you know how to do it" as I definitely do not. 🤷‍♀️ Hopefully the HVAC guy who is doing the install can assist a bit with guidance on a workable "keep it clean" setup. Don't want to overbuild but also don't want to end up blocking up the system with dust. 

 

Find it interesting that there are not add-on kits that are designed to deal with environmentally challenging situations like woodshops. Seems like it could be a great money maker for the company, and would ensure the solution wasn't causing more issues than the problem.

5 minutes ago, BB1 said:

 Hopefully the HVAC guy who is doing the install can assist a bit with guidance on a workable "keep it clean" setup. Don't want to overbuild but also don't want to end up blocking up the system with dust. 

 

Find it interesting that there are not add-on kits that are designed to deal with environmentally challenging situations like woodshops. Seems like it could be a great money maker for the company, and would ensure the solution wasn't causing more issues than the problem.

Actually, the setup that would work best with consumer-grade equipment is to install a room ceiling mounted dust collector and blow that air straight into the AC unit.  The AC units simply aren't really made for dusty environs.  Um, I wouldn't expect the typical AC tech to be all that good at woodshop stuff unless he happens to be a hobbyist himself.  "Add on kit" would be nice, but is such a fractional need/market that it's not attractive.  Welcome to the 1%. 

This might help:

https://www.amazon.com/Abestorm-Filtration-Collector-Woodworking-Adjustment/dp/B0DG2NG7BY/ref=sr_1_3_sspa?crid=5CVEKJ8WNY89&dib=eyJ2IjoiMSJ9.0tbgCRqCCV9UNKQcC5AY18wfaWz82nOMlIlKyi-coOfNWajuTtkYZklleNf6xKVEk6Ypiblxbxl2b64KlgWtvc55zIOhuqrcm5spBEwkv2eadA3Dk3xDjK7kv0NWPJ0sGomtqERTDXWGE6xRzFccENKuj4Fp8VYN-1ZlLYCB1mt1efP1GUpP2XH3JTXt7XeShy-_Oj4TnClMCn9VrELEbRej1cSoDjdIMuiAXOiO6aROtgEfZz2nGtsjxTl6_1kMFFi80XO3qwyc7TT3PuYYjLx9MPyIzmmesuAVAYcFrl8.RXbuUe2n1Un2VzmQyws_PSY7RHyzlx-Vbt8QioVWnHc&dib_tag=se&keywords=ceiling%2Bmounted%2Bdust%2Bcollector&qid=1767893871&sprefix=ceiling%2Bmounted%2Bdust%2Bcollector%2Caps%2C158&sr=8-3-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

1 hour ago, PeteM said:

This might help:

That looks interesting and cheaper than most of the traditional dust collectors (like Jet).

On 1/8/2026 at 1:46 AM, BB1 said:

Gerald - thank you so much for this! I think this is the product. Definitely looks to be much simpler. Have you noted any concerns with air flow limitations? When you say you have cleaned it twice -assume you mean the minisplit. Do these filters just get replaced?

Yes I mean the extra filter on the mini. I also clean the regular filter when I blow off the extra filter.

7 hours ago, Gerald said:

Yes I mean the extra filter on the mini. I also clean the regular filter when I blow off the extra filter.

How dirty did you find the inside vs outside filter? 

On 1/7/2026 at 10:51 PM, Gerald said:

My installer said I could lay filter material on top of the unit. This   Is actually filter material which you can cut to size and comes with velcro dots to attach. It comes n several sizes and one filter is enough to make two for my unit. I placed it on top and in the front to cover system filters.

Do you have a picture of your minisplit setup? I'm still trying to decide how to setup a pre-filter system.

try to get that tomorrow

On 1/10/2026 at 6:55 AM, BB1 said:

How dirty did you find the inside vs outside filter? 

After placing the extra material the inside on a quick glance looked clean

Hopefully the minisplit gets fully installed today. Saturday the motored vents into and out of the smaller room were installed and the pad was placed outside. 

1 hour ago, BB1 said:

Hopefully the minisplit gets fully installed today. Saturday the motored vents into and out of the smaller room were installed and the pad was placed outside. 

🤞🤞

Memory is just not what it used to be when I get in shop. The filters need a bit of dusting. 

 

best I can get of the top shows inside some. 
 

 

And this is the inside filter. Has not been cleaned in at least a month 

 

 

Gerald- Thank you for taking these pictures. If I'm seeing correctly, you have that blue mesh inside the unit over the minisplit filter plus some over the entire top (the exterior intake area)? 

 

My unit install is still a work in progress. 😕 I guess the supplier provided the wrong size copper line so now it's (hopefully) tomorrow for the install to be completed. They did get the outside unit set and other work. Really looking forward to this finally being done - especially as our weather is turning cold. 

No minisplit install today. Just received a call that he's waiting on the copper lines. Oh well, scheduled for tomorrow. Really looking forward to this being done as our temps have really dropped. Shop was about 40F this morning.