A house wall consists of 15 cm of brick (thermal conductivity 0.84 W m⁻¹ K⁻¹) over an…
PHYSICS · Subjective · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics
Problem
A house wall consists of 15 cm of brick (thermal conductivity 0.84 W m⁻¹ K⁻¹) over an area of 30 m². The interior wall surface is held at 20 °C while the exterior surface is at –5 °C. If an additional layer of fiberglass insulation (thermal conductivity 0.040 W m⁻¹ K⁻¹) is added to the outside, what thickness of fiberglass is required to reduce the steady-state heat loss through the wall to one-third of its present value? Express your answer in centimetres.