Question

look at the table of U-values on this page. Then explain why houses with small Windows are likely to lose less heat than those with larger Windows. Does this apply if the windows are double glazed and the wall cavities are insulated?​

Answer 1

Answer:

Explanation:

2.2.6 Calculating U-values of multiple layers of materials

Any thorough analysis of the thickness of insulation required to meet a specified U-value will require some detailed calculations. The earlier discussion of the basics of U-values only considered the thermal resistance of a single slab of a building material.

In any practical building element there will be extra thermal resistances, particularly those of the thin layers of air adhering to the outermost and innermost layers of the material, and the air in any substantial gap between the layers. Table 5 gives standard thermal values used for these. Note that the outside surface resistance is much lower than the value used for the inside surface. This is because the air is less likely to be still on the outside and will thus provide a relatively poorer insulation performance.