Non-residential minisplit sizing
What’s the process for getting a mini split accurately sized for cooling an industrial space? Is there something like a manual J? Can I trust a HVAC installer to do it right? Can/should I do it myself?
For background, I rent a large 900 sq. ft. rectangular room in a single story industrial building in zone 5 for my office/lab. The room has a tall sawtooth ceiling with no windows. The room’s walls are either adjacent to other rooms or a hallway opening on a loading dock. The loading dock doors usually stay closed on the hottest days, so the hallway usually isn’t quite as hot as it is outside. The walls are pretty leaky. I know the roof has some foam insulation, but I have no idea how much.
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In commercial & industrial spaces there is often higher plug loads, lighting, more occupants and other heat sources, as well as higher ventilation rates to account for, but the math is all the same. I surely doesn't hurt to do it yourself to at least get a baseline.
Trusting an HVAC installer requires some insight as to their methodology and experience in calculating loads. There are mechanical contractors who are true professionals and really great at it, then there are the rest. I suspect there are more true pros working in the commercial & industrial sector than in single family residential sector, but how good the average is in any particular region or location is hard to assess at a distance.