How does this calculation work?
We calculate the heat loss of your RV or camper van and translate it to fuel consumption:
Transmission loss
The surface area is estimated from the interior volume (6 x volume^(2/3) x 0.8 form factor). Transmission loss in watts is: surface area x temperature difference / R-value.
Ventilation loss
Warm air escapes through vents, gaps, and windows. This loss is calculated as: air changes per hour x volume x 0.34 Wh/(m3 per degree Kelvin) x temperature difference. In an RV, this typically accounts for 30-50% of total heat loss.
Safety margin
A 25% safety margin is applied to the calculated power requirement. This accounts for cold wind, humidity, unforeseen circumstances, and the fact that the heater does not always run at full capacity.
Fuel consumption
Diesel provides approximately 10 kWh per liter, propane approximately 12.87 kWh per kg. We use 85% efficiency for combustion heaters and 95% for electric heating.
FAQ
How much heating power do I need for my RV?
Most RVs and camper vans (6-10 m3) need 1000 to 2500 watts of heating power, depending on insulation and outside temperature. A well-insulated van in mild cold (32°F / 0°C) often needs only 1000-1500 watts. In severe frost (5°F / -15°C) or with poor insulation, this can rise to 3000 watts or more.
Which is better: a diesel heater or a gas heater?
A diesel heater (such as the popular Chinese parking heater) uses the same fuel as your engine and is cheap to buy. A gas heater (propane/butane) is quieter and has no exhaust fumes under the van. Diesel is slightly cheaper per kWh of heat. Gas requires a certified installation per local regulations.
Can I heat my RV electrically?
Electric heating from your battery is only feasible at low power levels (less than 500 watts, e.g. a heated blanket) or when on shore power. A full 2000-watt electric heater draws more than 160A from a 12V system, which is not practical. Consider diesel or gas as your main heating source.
How important is insulation for heating?
Insulation is the most important factor for your heating needs. A well-insulated van (R-value 2.5 or higher) needs up to 5x less heating power than an uninsulated van. Invest in insulation first before buying a bigger heater.
Why does ventilation count in the calculation?
In an RV, you lose 30-50% of your heat through ventilation and air leaks (gaps, windows, vents). This is necessary for fresh air and to prevent condensation, but it does increase your heating needs. The calculation accounts for this through the air changes per hour setting.