I have a 20 x 24 2 car garage that I use as a dedicated wood shop. It is attached to the house and has 2 walls concrete block, garage door in the front and stud wall in the rear connecting to the house. I live in Tampa, so it's pretty hot all year long. My old central AC took a poop this summer and we had a to purchase a new unit. I can only assume that there was some type of leak in the ducting of the old unit, Previously, even in the summer my shop temp was manageable. It was hot, but I could still work in there. Now during the summer it was unbearable to be in there in the daytime. Another weird issue is the projects that I stain and finish won't fully dry now. They stay tacky for days and I have to bring them in the house to fully dry.
So, I am thinking about a few options and would love any and all advice. I plane to put insulation in the attic over the shop, as it is currently insulated. R30 between the rafters (any advice on this, or is it as simple as it seems?). I'm thinking that would help the temp. I just looked up this item this morning to control humidity http://wizzvent.com/ . I am wondering if anyone has used this or anything similar. Can I use just a simple dehumidifier and save some $$$! Phase 3 of the plan would be a portable ac from craiglists. I would love a minisplit, but it maybe out of my budget. I don't need 70', anything under 80' would be great.
Any and all suggestions would be much appreciated! Thanks in advance for your help.