Van life · insulation
Van insulation R-value and thickness.
Pick a material and either a target R-value (to get the thickness) or a thickness (to get the R-value). Ranges, not single numbers, because the published values are ranges.
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Enter your numbers.
How thick should van insulation be?
Thickness = target R-value divided by R-value per inch. To reach R-10 you need about 1.7 inches of polyiso (about R-6 per inch), 2.0 inches of XPS (R-5 per inch) or 2.5 to 4.0 inches of fiberglass (R-2.5 to R-4 per inch).
Worked example. Target R-10 with XPS and a 1.5 inch cavity: 10 / 5 = 2.00 inches, which does not fit a 1.5 inch space, so the tool answers "No". Going the other way, 1.5 inches of XPS is R-7.5.
What the numbers are. The per-inch values come from Table 1 of the U.S. Department of Energy's Building America Solution Center: fiberglass batt or board 2.5 to 4, mineral wool rigid board 3 to 4, EPS 3.8 to 4.4, XPS 5, polyiso approximately 6 and high-density polyurethane spray foam approximately 6. Where the source gives a range, the tool gives a range.
Van caveat. This is the R-value of the insulation layer alone. Steel ribs, door frames and gaps carry heat around the insulation, so the whole wall performs worse than the layer on paper. Fit insulation snugly, seal air leaks, and treat the result as a planning number.
Frequently asked questions
How much insulation does a camper van need?
There is no published standard for vans. Pick a target R-value for your climate and enter it here; the tool gives the thickness for each material. Thicker is better until you run out of interior space.
What is the R-value per inch of XPS, polyiso and fiberglass?
The DOE Building America Solution Center lists XPS at 5, polyiso at approximately 6 and fiberglass batt or board at 2.5 to 4 R per inch.
Does this account for the metal ribs of the van?
No. It gives the R-value of the insulation layer only. Metal framing and gaps lower the performance of the real wall.
Is imperial R-value the same as the RSI used in Canada?
No. This tool uses imperial R-value (ft2 h F/Btu). Insulation labels in Canada often show both, so check which one you are reading before you compare.
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Planning estimate, not professional advice
Results are planning estimates from the numbers you enter. They are not professional, engineering, electrical or safety advice and are not a substitute for the manufacturer's instructions or local code. Check fire and vapour guidance for the material you choose, and follow the manufacturer's instructions for foam products in enclosed spaces.