RVs commonly fly at altitudes where heat is necessary, and of course, flying in the cold clear weather of winter is always exhilarating. It's a lot nicer if your lips aren't frozen together. Cabin heat is a must to get full pleasure and utility out of your airplane. Build your own custom system that works for you.
Keeping warm is only part of the comfort zone. Proper ventilation is a must for flying in the warmer months. The same canopies that give RV's excellent visibility also let in a lot of sun and temperatures in the cabin can quickly climb to uncomfortable levels. Cockpit ventilation is a must. The systems here have proven to be light, affordable and effective.
Note: The RV-7/8/9 ventilation system for both the fuselage and wing are provided as part of the fuselage kit.