The need for a tool for the use of energy assessors demonstrates the lack of technical expertise among the assessors. There is much evidence available already which would enable assessors to measure the heat loss in specific walls but to use it assessors require a knowledge of how to calculate heat loss. In my limited experience thus is lacking and the reliance is on the calculation in the EPC package which is notoriously inaccurate.

What is really needed is an online tool which enables home owners to measure the heat loss of their homes by inputting simple measurements of the different elements. The first result of such a tool would be to enable home owners to check the results of surveys carried out and the claims of installers more interested in profit than accurate results.