My friends that have a traditional furnace, are always complaining about the costs to heat. So, a friend has a infrared radiant tube style heater. His fuel costs are about 50% less than my friends. There is different configurations, so it is not a straight tube. You can do U-Tube as well. Just need to plumb the gas tubing on one end and have the vent on the other end. You save about 50% in fuel costs per year to heat. Here is a thread on where, I posted the other options.
https://lateral-g.net/forums/showthread.php4?t=39699
Do you plan to paint in the garage? If you do then you need an exhaust vent. As far as A/C units, there is a few options. Well, a friend has 40 x 28. He just has the window a/c style, but another option is the Split System.
http://www.residential.carrier.com/p...ll/index.shtml
Have you planned your lighting? I use T5-HO, but they work great. Each bulb lasts about 10,000 hours and use less electricity than T-8. You need to plan out your lighting, if you want to do infrared radiant heat. When I bought my T-5 HO in 2009, they weren't available but here is where I bought mine.
Jeff
http://www.vaultgarage.com/garage-lighting/