increase amount of heating increase surface area of walls increase number of windows increase thickness of insulation
I gave my students this multiple choice question: A building is found to be losing heat to the outside during the winter months. Which would be the best solution to correct this design problem?

Only one answer is correct among these 4 choices:
- increase amount of heating
- increase surface area of walls
- increase number of windows
- increase thickness of insulation

Could you tell me which one is correct?

increase thickness of insulation