"Hey Dan, I was informed that return and an air handlers unit will be installed in my garage in Florida. Does it need an enclosure? It's a three-ton unit. If yes, what are the dimensions of the enclosure?" It sounds like someone is installing an air handler in your garage which is completely fine. It may not need an enclosure. It's just going to depend on what your local codes say. If you need an enclosure, there's really not a way for me to tell you what the dimensions are. That would depend on the air handler and the details of the install, whatever your local codes for a garage in Florida say. I would ask that of your installer. You can also call your locals codes office and they should be able to tell you. More questions? Just leave them in the comments below.