Heater Sizing Calculator

kW heat output needed for your van's volume and ΔT.

About the Heater sizing calculator

Use this heater sizing calculator for van heating, gas & ventilation. kW heat output needed for your van's volume and ΔT.

Enter your heater sizing details

Your heater sizing results

Interior volume
18.98 m³
Heat loss at ΔT
0.17 kW
ΔT = 22 °C
Recommended heater
0.2 kW
With 20% headroom

Why heater sizing matters for van heating, gas & ventilation

Plan with confidence

Getting your heater sizing numbers right early avoids costly rework, undersized components and surprises on the road.

Related heating, gas & air tools

Pair this with the rest of our heating, gas & air calculators to plan your full van conversion.

Heater sizing calculator FAQ

What does the Heater Sizing Calculator do?
kW heat output needed for your van's volume and ΔT. It is designed for van heating, gas and ventilation so you can plan with confidence.
Is the heater sizing calculator free to use?
Yes. All VanTools calculators, including the Heater Sizing Calculator, are free to use with no sign-up required.
How accurate are the heater sizing results?
Results are estimates based on the values you enter and standard van heating, gas and ventilation assumptions. Always sanity-check against manufacturer data and your real-world conditions.
Can I share or save my heater sizing calculation?
Yes. Use the Share button to copy a link that includes your inputs, or use Export to download a PDF or image of your results.