How to Heat a Garage Workspace in the Winter
One very effective way is to be sure that your heat is not escaping your garage at the actual garage door. A good way to check this is to stand inside your garage with the lights out and garage doors closed. Look all the way around all garage doors and any side doors. You would be looking for light. If you spot light, you may need to invest in a rubber garage door strip from your local improvement store. It is easily enough installed by attaching it to the bottom of your garage door. If you have an old one currently on your garage door, you will need to remove that prior to attaching the new one. Home improvement stores also carry a weather stripping kit. You can use this to help seal around the sides and tops of your doors. Be sure and check all around your entire garage for any small holes or area that heat is actually escaping and many times it just takes a little bit of caulking to do the trick.
There are many garage heaters available both online and at retail locations that will effectively heat your garage. They range in price from $50 on up to $400 plus. I purchased an inexpensive garage heater for my husband to use in our garage (under $100) and it actually hangs from the ceiling. He hung it up in an area that he most often uses. I can tell you that it works pretty good for the money and mostly warms up the space he is working in.
In our garage we were fortunate to have exposed duct work at the ceiling areas. My husband did insulate all of those but he also purchased a small heat vent and carefully cut the hole in the duct to fit the vent. He then is able to snag some of the heat from our living area into his garage area. This also gives him the flexibility of closing the vent for days at a time should he not be working in the garage area.