Air Conditioning a Workshop: A Follow Up

by Patrick Harper - Blood, Sweat, and Sawdust

Air Conditioning a Workshop

Nothing kills my spirit like a hot, humid workshop.  In the past, I avoided the workshop for the entire summer.  So when we decided to move, an air-conditioned workshop was at the top of my list.  I figured the cost would justify itself in a single summer.  Georgia summers are long and damp.

If you haven’t yet, check out the ductless mini-split air-conditioner installation.

The Benefits

My unit is a 12,000btu Mitsubishi Mr. Slim heat-pump.  It provides heating as well as cooling.  While it is pricier than a window unit, it is much more efficient.  In fact, I keep the shop at a cool 70 degrees, and there hasn’t been a noticeable increase in our power bill.

Another plus is noise.  The unit is very quiet.  It is an excellent choice for anyone who makes video.

The unit is also small.  The indoor unit occupies very little wall space.  You’ll forget it’s even there.


  • Dust.  Workshops are full of it.  Air-conditioners hate it.  Clean your filters often.  My manual states that the filters should be cleaned every couple of weeks.  I clean mine at least once a week.  Fortunately, this only takes a few minutes.
  • Fan Speed.  A few days after the heat hit, I noticed that the thermometer on one side of my shop was reading high.  Initially, I thought it was because I hadn’t yet blown insulation into the attic.  Worse, I feared that I purchased an undersized unit.  Upon further investigation, I determined that the cause was fan speed.  The auto-speed option set the fan speed to its lowest option.  Increasing the fan speed fixed the problem.  Apparently, I don’t have good air circulation in the workshop.
  • Moisture.  The Mr. Slim does a decent job of removing moisture out of the air.  Like most air-conditioners, it works better on warmer days.  It’s the cool, humid days that give most conditioners trouble.  This is because they simply aren’t running long enough to dehumidify.  Fortunately, the Mr. Slim has a dry operational mode.  This keeps the unit just below the dew point and allows the unit to remove moisture even on cooler days.  However, if your workshop is particularly damp, you may still want to consider a separate dehumidifier.

In conclusion, the Mr. Slim mini-split air-conditioner proves to be a great investment.  It allows me to spend several more months in the shop each year than I would otherwise.  Even better, it makes the shop more comfortable and I hardly even know it’s there.  If you have the means, I highly recommend one.