Home / Van Insulation Material Calculator
Van Insulation Material Calculator
Work out how much insulation to buy and the overall thermal resistance (R-value) it will give your finished van.
Material needed for wall, ceiling and floor
Enter the surface area of each section you're insulating in square meters; the tool adds them together, then adds a waste allowance for offcuts and mistakes before dividing by how much area one package of your chosen material covers, rounding up to a whole number of packages.
Estimating your overall R-value
Each insulation material has a typical thermal resistance per centimeter of thickness (its R-value per cm, in m²·K/W). Multiplying that by the thickness you plan to install gives an estimate of the overall R-value your insulation layer will achieve — a rough guide for comparing materials and thicknesses, not a certified thermal report.
Frequently asked questions
How is the R-value per cm figure used?
Multiplying a material's R-value per cm of thickness by how many centimeters you install gives the overall thermal resistance for that layer — thicker insulation of the same material always gives a higher R-value, up to the point where wall cavity depth runs out.
Why does the calculator add extra material for waste?
Cutting insulation around wheel wells, ribs, window openings and curved panels always produces offcuts and mistakes — the built-in waste allowance means you're less likely to run short mid-install and have to wait on a second order.
Is a higher R-value always better for a van?
Higher R-value improves temperature stability and reduces energy needed for heating and cooling, but thickness eats into your interior space and adds weight — most van builds settle for the best R-value that still fits comfortably inside the wall cavities.
Can I mix different insulation materials in one build?
Yes, and many builders do — for example rigid foam board in flat wall cavities and a flexible batt or spray product around ribs and irregular shapes. Run each material through this calculator separately and add the results together.