Physics · May / June 2023 · Paper 11 · Question 18

A house is to be thermally insulated to reduce thermal energy loss and reduce fuel costs. [diagram of a house showing: loft insulation: installation cost, $300, energy cost saving, $300 per year; cavity wall insulation: installation cost, $700, energy cost saving, $200 per year; draught proofing: installation cost, $100, energy cost saving, $30 per year; double glazing: installation cost, $7000, energy cost saving, $400 per year] Which type of thermal insulation pays back the cost of installation in the shortest time?

1. Acavity wall insulation
2. Bdouble glazing
3. Cdraught proofing
4. Dloft insulation

As printed in the paper