I know there are a lot of DIY guys out there. I just built an 800sqft garage. It is insulated all around with R19 in the walls and R34 above. Insulated garage door and double paned windows. How well insulated...-1F last night and garage got down to 43....that is not bad. So here is the question.
I do not want to use anything that requires venting, but I want to have a heater in there. Kerosene is out as is a wood stove. I want to spend $100 or less. Recommendations please that will not cost too much to run?
Don:
Natural gas will be cheapest to run, but it requires venting and the units are not under $100.
Several years back I insulated my attached garage - about 30 feet by 40 feet in size - with R19 in the walls, R52 in the ceiling, and installed a steel, foam cored double garage door, having one good sized window with double pane and low-E glass, etc.
I heat this structure with two King Compact Room Heaters - PAW Series, Pic-A-Watt, specifically PAW24221. They are about 6 inches high by 12 inches wide by 4 inches deep. They fit inside a wall can that comes with the heater. These are both 240 Volt units that I run at 1500 watts each, for a total of 3000 watts when operating. I used an old electric water heater circuit rated for 30 amps? I don't remember - that we replaced with natural gas. I have a thermostat that I set for 50 degrees F - just to keep things from freezing. These are wall mounted units - mounted between the wall studs. They have blower motor fans and I have no trouble keeping my garage well above 50 degrees.
The nice thing about the Pic-A-Watt series is that you can select the current input from 500 Watts to 2250 watts just by changing the arrangement of the internal jumper wires. You can change these jumper wires after the fact so that you can increase or decrease the power of the unit at will. I have been running these units for four years now - with no issues.
These wall mounted units are much safer, more durable and more flexible that the Milk-House-Heaters. I went through several of the Milk-House-Heaters in the past. I found that they tended to rust, and the thermostats were not reliable.
Good luck with your install...