Building regulations - new domestic buildings: identification and assessment of energy standard improvements

8. Cost Impact Assessment

The results in Table 19 below illustrate the net cost / benefits of moving either to Good Practice or Best Practice standard in comparison to the BAU scenario of compliance with current regulations. The results are illustrated for analysis using HEM, SAP and PHPP energy modelling methodologies for the central build rate scenario.

* Benefits are illustrated as positive, with costs illustrated as negative.

The net present costs of moving to good or best practice standards are £213 or £1,460 million respectively once capital, maintenance and replacement costs are considered.

The once benefits from reduced energy costs, carbon emissions and better air quality are included the results show that neither the good or best practice standards deliver a net benefit in comparison to the current regulations when modelled with HEM or SAP. Using the PHPP energy model, the good practice standard achieves a £1million net benefit but there is no net benefit for the best practice standard.

The total carbon benefits of the good and best practice options average 0.69-1.39 tonnes CO₂e per home over 60 years from a move to best practice from current regulations and 0.20 to 0.43 tonnes CO₂e over 60 years from a move to good practice. These relatively modest savings are a result of the counterfactual of current regulations assuming the same mix of low carbon heating systems as the New Build Heat Standard options (i.e. ASHP, DE and DHN). As a result, the carbon and air quality benefits of the considered options are exclusively those linked to energy efficiency measures or additional renewable energy generation. Because the energy being saved is already low carbon the value of these savings is proportionately smaller than might be the case where the policy options entail a switch in technology to heat pumps or other low carbon sources.