Energy savings from sealed double and heat reflecting glazing units

Results are presented on the comparative energy consumption of houses with single, double and heat reflecting glazing. The experiments were carried out in the BRE 'matched house pairs with simulated occupany' described. Under the given environmental conditions the main results show a saving in space heating consumption of 9% (±2%) for double glazing and 10% (±2%) for heat reflecting glazing compared with single glazing. Theoretical energy balance calculations using the thermal properties of the houses and the measured mean seasonal weather data and internal temperatures give approximately the same savings as measured. Using this energy balance to extrapolate to larger glazing areas shows that the energy requirements increase for single glazing but decrease for double and heat reflecting glazing. The predicted savings substantially support the Building Regulations Approved Document L2/3. Reducing curtain closing times increases the energy requirements significantly for single glazing but has only a small e...