ᐅ It's getting hot in here - With Dometic's RV Furnaces How to Find the Best RV Furnace. Dometic understands RVs come in many different sizes. We offer heating capacities ranging between 12,000 and 40,000 BTUs to match individual vehicle sizes and needs. You will need to compare the heating requirements of your RV with the capacity of our heating systems. The Perfect RV Furnaces for your Requirements ᐅ Furnaces - Optimal Heat Source for your RV | Dometic RV Furnaces. If you are planning to travel when the weather’s cold, a heat source is a must. Dometic provides a selection of furnaces to keep you warm – even if it’s well below zero outside. Engineered for easy maintenance and excellent air delivery, our lightweight products are compact and reliable. Multiple duct options are available.