Most people do not bother to put any sort of heat in an linked 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 linked to the home it seldom drops to below freezing due to the transference of residual heat from the home itself. In our case the two of us had a giant attic space above the garage and in order to use it the two of us needed some sort of climate control. During the Summer weeks the two of us simply used fans and vents to eliminate the excess heat, but while in the Winter time the two of us needed a form of heat that was cost effective and didn’t require ductwork. The forced air method in the home was not giant enough to affix to the additional space so the two of us wanted something totally separate. We consulted with our Heating as well as Air Conditioning company and she proposed that the two of us look into some sort of radiant furnace, then as it is an attic space she said that if the two of us 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, however she also said that if the two of us favorite the two of us could use infrared radiant tube gas gas furnaces that would be installed along the ceiling if the two of us didn’t want to worry about blocking the heat source, but we were blissful to hear that the two of us had so various opportunities available and decided to go with the baseboard registers, and now the two of us have the ability to store more things safely and not worry about the temperature in the attic no matter what season it is.