Garage heater, best decision I have made in a long time.
 

I put in an RV/Boat/Truck diesel air heater over this winter and it has turned out to work far better than I could have hoped. They run about $120 off ebay for an "8kw" one, though judging by fuel usage, I bet it's closer to 6kw. Uses maybe a gallon of heating oil for ~8h of run time and, while it can't keep the garage toasty, it brought it up from 30F to 55F using it and my 1500w IR heater together. And the best part is, since the intake and exhaust are external, no fumes or moisture buildup.

The garage is a 21x20ft, full cinder block, detached garage. No insulation, gaps around the doors, two single pane windows, and the ceiling is sagging beaver board with no sealing of the gaps between panels. So this place does not hold heat well at all, but this little heater makes it a way more comfortable place to work in the dead of winter. In a smaller space, or one with even some insulation, I am sure it would be nice and warm.

The hardest part of the install was getting two, 1.25" holes through the cinder block for intake and exhaust. I used a combo of a 1/2" masonry bit on a cheap old hammer drill and an on school 1.25" hammer drill to get it done.

Made a wall bracket and a control panel to hold everything (excuse the messy wiring, I still need to clean it up.) The only thing that didn't come in the kit was the 12V power supply to run it.

https://www.miataturbo.net/attachmen...1&d=1585398921

https://www.miataturbo.net/attachmen...1&d=1585398921

https://www.miataturbo.net/attachmen...1&d=1585398921

https://www.miataturbo.net/attachmen...1&d=1585398921

A heated (and air conditioned!) garage is the best thing ever. My friends hate it though because I no longer go to their houses to help them fix their stuff because I'd rather work in my climate controlled garage haha.

Truth! I run a window unit in the summer.