Type of shop, how you plan on using it, and the type of work you plan to perform should be considered as much as the type of HVAC system. Since you are talking heat, will your shop be closed up tight to limit heat loss? Air quality whether it be from dust, welding smoke, paint fumes, etc. can be a real problem for our health working in the shop. Type of Contaminants/Air Quality/Fresh Air are key considerations. A ductless mini split is a marginal performer in dealing with these issues in the shop. If your chosen solution addresses these issues by other means, then a ductless system might be the best solution for your shop and type of work. I personally like PugetDude’s shop HVAC solution, good air filtration and air distribution without the hassle of cleaning the mini split wall mounted evaporator periodically. Not necessarily a inexpensive approach but handles the filtering/cleaning problem with easily replaced standard (cheap) filters. Not sure what type of filter Puget Dude is using but these newer compact filters that are HEPA/Merv ** rated look like they will do a pretty decent job of clearing the air of fine particulates found in the shop. Augmenting the air filtering to handle large amounts of dust generated in a closed shop space is something to think about. As soon as the supply chain can cough up my back ordered equipment, I am installing a system similar to Puget Dude‘s (minus the diamond plate). I don’t really have a good approach to address make up fresh air. A fresh air heat exchanger is beyond my budget currently. I am in Phoenix, so my focus is on cooling but my shop closes up pretty tight to manage the hellacious summer heat. Air quality inside my shop is something I think about a lot. I should have done a better job of protecting my lungs in the shop as a younger fabricator. My current plan is to keep welding, grinding, painting, solvent cleaning, etc. to the cooler morning hours outside. It isn’t ideal but my lungs and budget appreciate it. I’m not much of a woodworker but this strategy works for me. Best of luck with your shop.
