Apparently 70% of people would find a energy efficient home attractive when deciding to buy. The Energy Performance Certificate (EPC, in the HIPS packs) is the most relevant document to this section and will give you a rating between A and G.
The EPC looks at the Energy efficiency rating and the Environmental Carbon Dioxide Impact rating for the average property in the UK falling in the D-G range.
This rating is generally based on the building itself and its services rather then the appliances which form what is called an asset rating. Therefore, any improvements that are made to your home need to create long term benefits to improve your rating.