Question

Little Pig's House:

• The walls are made of 10-cm thick bricks, insulated with 5 cm of fibreglass. They cover a total area of 45 m2.
• The floor is thick and well insulated.
• The 15-m2 roof is made out of ceramic tiles that are 2.5 cm thick and insulated with 5-cm thick fibreglass.
• The door is 3.5-cm thick solid wood with an area of 2.0 m2.
• There are double-paned windows with a combined area of 4.0 m2. Each window is identical, having two 3-mm thick glass panes with a 2-mm air gap between the panes.
• An electric heater heats the house’s interior. The pigs themselves contribute in heating via metabolic power (each pig contributes ?meta=100 W).

Assuming that each pig contributes 100 W of metabolic power, calculate the power required from the heater to maintain the inside temperature at 20 ∘C, when the outside temperature is 8.5 ∘C. Give your answer in W.

Answer 1