a. Calculate the heat loss from a building 12.000 m x 6.732 m x 2.500 m high. There are 6 windows each measuring 1.2 m x 1.2 m, hardwood front door measuring 0.762 x 1.981 and a back door fully glazed 0.762 x 1.981. There is a 21 °C temperature difference between the internal environment and the external air. The U values are:

• Walls 0.95 W/m2°C • Windows 5.30 W/m2°C • Floors 0.45 W/m2°C • Roof 0.20 W/m2°C • Front Door 1.88 W/m2°C • Back Door 5.30 W/m2°C

Ventilation Heat Loss = 0.361 x No of air changes (say 2) x Volume x Temp Difference.

M1
b. Calculate the energy saving if the U value of the wall is improved, with the inclusion of insulation, to give a new U value of 0.3 W/m2°C