Infrared heaters are effective and a preference for many because it burns propane. BTU's vary and so does the coverage area, but typically, these units warm a large space in a very short time. The infrared heater attached to a propane tank is an added bonus to provide immediate warmth to a personal space. Like a sun lamp, this option creates warmth instantly.
This is what I use and honestly it works great for me granted I think I should have went for the single instead of the double. It takes up very little space, heats up my insulated 2 car garage very quickly, Makes for a comfortable place to smoke my cigars in the winter. If you want to go fancy the the electrical baseboard heaters are the way to go but any electrical heating element will run that power bill sky high. Me I can't afford the cost equivalent of another stove, hot water heater, or dryer (the three biggest power consumers in the home) but if you have it to blow then go for it I say.
https://www.harborfreight.com/30000-btu-tank-top-propane-heater-63072.html