Computer Thermal Modelling using TRNSYS [9] and ECOTECT [10] software programmes provided an estimate of the thermal demands in the dwelling types modelled, as well as the potential carbon savings achievable through changing the heating, cooling and DHW demands from being primarily met by natural gas to primarily met by Solar Thermal. An existing dwelling was chosen to be representative for each of the housing types highlighted in Error! Reference source not found. and was then physically surveyed in detail [3]. Each dwelling was then modelled in ECOTECT before exporting the physical details into the TRNSYS simulation software to undertaken the energy demand assessments.

Only 12 out of the 13 housing types have been modelled to date — the most recent house type has not yet been modelled. The ECOTECT model for the largest dwelling, house 3, is shown in figure 2 as an example of the modelling undertaken. This image shows how the Solar Thermal collectors have been arranged for this property for the purposes of assessing the potential solar yield.

Table 2. Predicted annual energy demands for electricity, space heating, space cooling and domestic hot water

It can be seen that the dwellings thermal demand generally reduces per m2 as their construction date gets closer to the present day. It can also be seen that the internal gains from electricity use also become more important in the overall energy balance as the houses become newer. There are anomalies as would be expected from Case Studies — in particular House 1 which is explained by it being a very energy efficient refurbishment. Interestingly, this house compares very favourably with House 11 built to 2000 regulations, showing the potential for bringing old housing stock back into use.