A wall furnace can be and eyesore in any room, especially as it gets older. The paint will start to chip, or just fade over time from being exposed to heat for long periods of time. You can make it look new again with the right paint, and the right process to paint it.
Step 1 - Sand the Surface
To get started, turn off the heat. Next, lay down the drop cloth to catch any debris. Grab your sandpaper and sand the entire surface well to move any loose paint and any debris stuck on your wall furnace. The sanding will also give your paint something to stick to. Wipe it down with a tack cloth when you are finished, and you'll be ready to paint.
Step 2 - Painting
Ventilate the room well by opening windows. Put on your ventilator mask and paint the wall furnace with a paintbrush paying attention to any nooks and crannies. Allow it to dry completely before turning the heat back on. When you do turn it back on, it will have a bad odor from the new paint. Keep your windows open for a while. It will dissipate after a couple of hours.