Our U-value estimator is designed to give you a helpful indication of how different build-ups may perform, supporting early planning and helping you explore breathable, low-carbon options with confidence. Because every building is unique — especially in retrofit — these figures are only a guide, not a final specification. For an accurate, project-specific calculation, we always recommend getting in touch with our team, who can provide full guidance on moisture risk, build-up suitability and regulatory compliance. And if the best route forward isn’t with Sisalwool, we’ll still point you in the right direction — because healthier, better-performing buildings matter more than sales.

These figures are a conservative representation and better values can be achieved depending on the specific build up.