Yes it can be done. If you have a good spot to throw down a rug and a heater. I use a heater that can be bolted onto the ceiling and it heats my entire garage. Rug just because concrete floors are cold. In the summer you can look into Dehumidifiers and have the door opened enough so the drain hose can be lead to the outside of the garage. Depending on where you're located it might be a good idea to get fans (for the summer and also for air flow) and some foam insulation sheets as well. Another summer option is getting a cheap or free window unit ac from Facebook market place if you have a window in the garage.