on my 1845c, I used lexan. Welded up a front door with a U channel and slide a piece of lexan in.
Then bolted 2 more peices directly to the ROPS on the side.
Worked great for many years and kept it toasty in the cab while plowing.
1845c has plenty of space on the rear deck above the engine.
I ran a coolant heater mounted up there with lines down to the engine.
Only downside was the heat didn't get down by my feet.
The Eterra Cab Heater for Skid Steer Loaders provides a simple solution to operating any equipment in the cold. Stay warm and toasty with an Eterra Cab Heater.