Most people do not bother to put any sort of heat in an attached garage.
This is because the car and some storage things are there and these are not affected by varying temperatures.
Plus, if the garage is attached to the house it seldom drops to below freezing due to the transference of residual heat from the house itself. In our case we had a large attic space above the garage and in order to use it we needed some sort of climate control. During the summer months we simply used fans and vents to eliminate the excess heat, but during the winter we needed a form of heat that was cost effective and didn’t require ductwork. The forced air system in the house was not large enough to connect to the additional space so we wanted something totally separate. We consulted with our HVAC dealer and he suggested that we look into some sort of radiant heating system. As it is an attic space he said that if we installed electric baseboard heating it would be best. We would just have to position the items in there so that they were not blocking the registers. He also said that if we preferred we could use infrared radiant tube heaters that would be installed along the ceiling if we didn’t want to worry about blocking the heat source. We were glad to hear that we had so many options available and decided to go with the baseboard registers. Now we have the ability to store more things safely and not worry about the temperature in the attic no matter what season it is.