A DIY garage mini split can warm your shop, but fit, leaks, and power count....

https://brookssuniqueblog.theburnward.com/how-many-btus-for-a-1-car-garage-200-to-300-sq-ft-in-winter

A DIY garage mini split can warm your shop, but fit, leaks, and power count. Learn to size it, check a 15A breaker, seal gaps, and price the job