Mini split ductless maintenance & shop dust

[pete hagan]

I’ve been reading through the posts concerning mini split HVAC systems for use in a shop and wondering how much extra maintenance people have experienced using them in a shop setting? I have settled on using a mini split system in my 1200 square-foot metal building shop that is pretty well insulated. My concern is if the added dust from a wood shop environment creates additional opportunities for mold and mildew buildup in these mini split ductless systems. I can go with a ducted system fairly easily which would allow for more robust filtration however if the ductless units have not had that much of an issue with maintenance that is a much easier route to go. Please chime in and let me know your experience.

[Tom Bain]

I have not had any issues with my mini-splits. You do need to clean the filters on a regular basis, which are mesh-type filter than can easily be cleaned with water. I’ve had mine in the shop for ~6 years and did have the local HVAC company come out once to preventively give it a more thorough cleaning and tune-up. I’ve never had a ducted system in the shop, but in generally the mini-split has been less maintenance than more traditional heat-pumps in my experience.

[Jim Becker]

Zero issue with my mini-split. I just clean the interior unit with some frequency given the environment and how close it is to my CNC machine.

[Jack Frederick]

Yours is the right question to ask. When the unit is installed make sure that you have the installer show you how to remove and re-install the cover so you can do your own cleanings. Mini-splits have very fine fin spacing and over time you will have to clean the coil and the blower wheel, which loads up and affects air flow a bit. I do mine in the house every couple years...and am due Tom and Jim have both had good results because their units are properly installed. Where you typically have issues with mold, mildew etc is where the unit is not draining completely, especially so in a humid environment. When I lived back east and humidity was a factor in my life I used "dry mode" on my remote in shut-down. It would run to dry the coil and drain pan prior to shut-down. Here in CA foothills it is dryer than a popcorn f*** and not necessary. In humid areas I like that feature. Regardless of ducted or 'less, how is your dust collection? Whatever is airborne will go through both. At least with a ms you can see it. I represent Fujitsu in the six New England States from '97-'11 when I sold the business and have had Fujitsu's in my homes for 20 yrs now. I'm a fan. Oh, get your condensing unit off the ground. I wall mount mine with Air-tec wall brackets. It keeps thm cleaner. Don't oversize the system.

[Charles Lent]

I have seen where some have built filter boxes to allow for pleated furnace filters to be used on the air intake to their ductless units. If I go with a mini-split unit in the future, I'll likely do this. My 24,000 btu window style heat pump is mounted through the wall, is 16 years old, and is beginning to have problems. I've been buying 12 X 20" pleated furnace filters for it, since I discovered that they will just fit behind the plastic cover and completely cover the inside coil assembly. I've been blowing them out or replacing them about once a month when using the shop frequently. It's been my shop air filter as well as for heat/cool. The replacement for my unit will very likely be a ductless unit with an added filter box, and I'll close up the hole where the existing unit is now.

Charley