Please suggest occasional heating for garage used as work room
Workroom...shop...dust...occasional use...gas...electricity...seems like lots of variables. 

This guy seems to know what he’s talking about:

https://www.thewoodwhisperer.com/videos/shop-heating-options/

Remember, the difference between infrared heat and forced air is that infrared heats the objects in your shop BEFORE it heats the space (air) and forced air heats the space BEFORE the objects. This could be important depending on how long you’re going to be working in your shop.