From my Raptor days to our Class A now I have 3 small quiet space heater that I run on low or use the thermostat. In a small space like a garage they do a great job. We still use them, usually just running 1 or 2 at a time. I place these where our dogs will not knock them over and our kids are old enough to know. The Holmes pictured below is my favorite of them, its very quiet when the fan blows but the indicator light reminds me it's on. Wish I'd bought a couple more of them.
If we have hook up's I set these and don't worry, the propane system kicks on enough to bring the temp up when it's very cold, these just augment that system.