Klimat-, kostnads- och teknisk jämförelse av isoleringsmaterial för ytterväggar (PIR, EPS, hampafiber och fårull) : En fallstuide av ett lagerhus

Sammanfattning

The construction sector accounts for a significant share of society's energy use and climate impact, where the choice of insulation material in external walls plays a central role. The purpose of this thesis is to compare the insulation materials PIR, EPS, hemp fibre and sheep wool with regard to climate impact, costs and technical properties, as well as to analyse how well theoretical calculations correspond to actual thermal performance in a building with varying temperature zones.Thermographic imaging was conducted on an existing PIR-insulated warehouse, where measured surface temperatures formed the basis for calculating U-values and thermal efficiency. The results show that measurement points at the centre of the wall were relatively close to the theoretical U-value, while points near slab–wall junctions and corners deviated considerably due to thermal bridges and joints. Some measurement uncertainty exists and the figures should be interpreted as indicators of patterns rather than absolute values.Climate impact was analysed using LCA (modules A1–A5, C1–C4 and D) based on EPDs. At a comparable R-value (approx. 9.1 m²K/W), the climate impact of the insulation materials amounts to about 36, 30, 8 and 3 kg CO₂e/m² for PIR, EPS, sheep wool and hemp fibre respectively. For complete wall assemblies (U = 0.108 W/m²K), the corresponding values are about 52, 45, 36 and 30 kg CO₂e/m². The cost analysis from Bidcon shows that EPS is the least expensive (about 700 SEK/m²), followed by PIR (about 1300 SEK/m²), hemp fibre (about 2000 SEK/m²) and sheep wool (about 2300 SEK/m²). The higher cost of bio-based materials is attributable to stud frame construction, additional layers and increased labour.Technically, PIR has the lowest thermal conductivity (λ = 0.022 W/mK) and yields the thinnest wall assembly (201 mm), compared to EPS at 336 mm, sheep wool at 474 mm and hemp fibre at 524 mm. PIR and sheep wool were found to be more fire-resistant (classification D-s2, d0) than EPS and hemp fibre (classification E).Bio-based materials require more careful moisture management than fossil-based alternatives. Service life is 50 years for sheep wool and 60 years for hemp fibre, while PIR and EPS are expected to last as long as the building component they form part of.In conclusion, PIR is the most cost-effective and space-efficient option but carries the highest climate impact, while hemp fibre stands out environmentally despite its higher cost and wall thickness. The thermographic survey confirms that thermal bridges at junctions and corners are critical to real-world performance, and that theoretical U-values should be supplemented with field measurements for a more accurate assessment.