What it costs: curtain wall glazing | Features

Specification options: glazing for curtain walls (nominal cleaning and energy costs included)
	Capital cost (£/m2)	Life-cycle cost (£/m2 over 60 years)	Expected service life (years)
Single glazed; 10mm toughened glass to BS EN 12150; 5.6 W/m2K	35-45	262	60+
Double glazed; clear glass; 6-16-6; 2.7 W/m2K	50-60	228	20-50
Double glazed; Low-E glass; 6-16-6; 1.7 W/m2K	56-66	217	20-50
Double glazed; Low-E glass; argon filled; 6-16-6; 1.5 W/m2K	60-70	216	20-50
Double glazed; Low-E glass; argon filled; 6-16-6; 1.5 W/m2K, self-cleaning	95-105	219	20-50
Table notes A discount rate of 3% is used to calculate net present values. Energy and cleaning costs are nominal and illustrative only. Costs are vary enormously. Key factors include fuel type and tariff paid; location, geometry, size, height, complexity and orientation of building; area of glazing, thermal insulation properties of non-glazing fabric, heating and cooling system; occupancy patterns and thermal requirements. Cleaning costs will be influenced by external environment, for example, level of pollutants, access provision and level of cleaning required. Capital costs are for the glazing only. Insulated glass units to BS EN 1279. U-values relate to centre pane. Life cycle costs are indicative and are based on the average of capital costs and service lives. A cost analysis based on project specific information is essential for a realistic best value appraisal.