Address the insulation material as homogeneous, Even though in genuine apps, rigid resources have joints and even cracks. Therefore, the U-benefit is usually better than what it would be In case the insulation behaved to be a homogeneous substance. Reference 2 supplies advice on calculating U-values. It could be noticed https://glazinginstallation48147.bloggazza.com/33622826/not-known-details-about-draft-proofing