Financial Calculations

Heat Loss Through Walls


The table below shows a breakdown of the heat lost through the various surfaces of the 1970's Wimpey house this study is based on. It shows

  • Heat loss without insulation. (As it was when the house was first built).
  • Heat loss with insulation installed.
  • The heat loss expressed as a percentage of the total.
  • The annual cost of the heat loss.
 
With respect to the walls the addition of cavity wall insulation was calculated to

  • Reduce the heat loss by 61%



Heat Loss without insulation.

(W/K)


Heat Loss with Insulation.

(W/K)


Improvement

(%)

Roof 297 (45%)
10 (5%)
97
Walls 177 (27%)
69 (34%)
61
Doors and Windows 133 (20%)
86 (42%)
35
Floor 52 (8%)
40 (20%)
23
Total 659
205