With the cold weather in full force, many garages tend to become refrigerators. Without proper preparation and hardware, the garage is no place to be in the cold. Fortunately, there are some simple steps to take that can help warm up the garage.
First, make sure any walk-through doors are well sealed. For walk-through doors, make sure the hinges are aligned, the door is sitting flush, and the latch is catching well. From there, check the bottom seal on the door itself and the seal around the door opening. If these are torn, falling off, or have been falttened over time you should consider replacing them. Replacement door seals are relatively cheap and easy to install.
Second, make sure the garage door itself is well sealed. Ensure the door is sitting flush and level against the driveway. Check the outside of the garage door with the door in the closed position. Make sure that the seals are flish around the entire perimeter of the door. Next, check the bottom seal. This typically slides into grooves on the bottom edge of the door. If there are significant gaps between the garage door and frame, the tracks may need to be adjusted to get a better seal. Enlist a garage repair professional to perform these adjustments.
Third, the garage door itself is commonly a thin material. Insulating this yourself is a hassle, is an eyesore, and can be a hazard to the safety and operation of your garage door. Consider upgrading to an insulated garage door. Not only will the installer make sure the tracks and seals are perfect, but the door itself will significantly improve temperature stability in your garage.
Likely your garage's outside walls are not insulated so once you've ensured a good seal in all of the doors and garage door, consider insulating the walls. If your walls are finished/drywalled, this will be more tedious and may call for blown insulation. If your walls are not finished, you may be able to easily apply insulation yourself. Don't forget if you have attic space above your garage to insulate that as well. Blown insulation in this attic space is the way to go.
If you want to take heating up your garage to the next level, consider an indoor portable heating unit or a "mini split" HVAC unit.