A clear view | Archive Titles

TABLE 1: The Window Information System calculation tool
Window surface area	1000 m²	Cost of natural gas for heating	0.027 £/kWh
Costs of electricity for cooling	0.10 £/kWh	Average outside temperature	9°C
Solar irradiation	753 W/m²	Average inside temperature	20°C
Average sunshine hours/day (all of above figures cam be changed by user)	3	Average hours of thermal loss/day	14
Comparison of window systems and energy costs	Glazing Single 3 mm glazing	Internal shading + glazing Verasol 812 + 3 mm glazing
Solar factor (g-value)	87	28
U-value	5·9	2·2
Air conditioning
Solar energy entering m² of window	655 W/m²	211 W/m²
Solar energy entering through windows	55·1 kW	210·8 kW
Annual savings on electricity			243 238 kWh
Annual CO₂ emission	225 964 kg	72 724 kg
Annual reduction of CO₂ emission			153 240 kg
Annual costs for cooling (1 kW = £0.10)	£35 867	£11 543
Annual savings on air conditioning			£24 324
Heating
Energy loss through windows	64·9 kW	24·2 kW
Required quantity of natural gas/year	414 549 kWh	154 578 kWh
Annual savings on natural gas			259 971 kWh
Annual CO₂ emission	77 935 kg	29 061 kg
Annual reduction of CO₂ emission			48 875 kg
Annual costs for heating (1 kWh = £0.027)	£11 193	£4174
Annual savings on heating			£7019
Total annual reduction of CO₂ emission			202 114 kg
Total annual savings on a/c and heating			£31 343