Scottish Government

CHAPTER TWO RESEARCH METHODOLOGY

2.1 The methodology adopted for this study broadly follows that of similar studies of this nature in that a series of baseline dwelling types were defined, for which cost plans and energy calculations were prepared as a basis for comparing alternative improvement scenarios.

2.2 The key steps in our methodology are summarised in the following flow chart.

Step 1: Definition and sign-off of approach

2.3 This stage included agreeing the detailed elements of the methodology with the project steering group, including:

• The analysis parameters, including discount rates for the lifecycle costing analysis, residual value calculation basis, costs to be included/excluded from the lifecycle cost models;
• Review of existing Communities Scotland cost data;
• Basis of defining the baseline projects, including assumptions on dwelling design, specification, configuration etc;
• Locational issues to be factored into the models;
• How the findings were to be presented and analysed.

This stage is discussed further in chapter 3 of this report.

Step 2: Establish baseline costs

2.4 This step comprised the establishment of baseline capital and lifecycle cost models for the baseline dwellings. The methodology and assumptions are explored further in chapters 4 and 5 of this report.

Step 3: Identify potential options for achieving EcoHomes standards and CO ₂ reductions

2.5 Standard Assessment Procedure ( SAP)-based energy models were prepared for each dwelling type and used to assess a wide range of potential CO ₂ improvements including both individual items and grouped improvement scenarios. Similarly, EcoHomes analysis sheets were developed and used in the identification of potential improvements.

2.6 The basis of the SAP calculations is described in chapter 3 of this report and the methodology and outcome of the EcoHomes and CO ₂ improvement scenarios are discussed in detail in chapters 6 and 7 respectively.

Step 4: Apply EcoHomes standards and CO ₂ reduction options to baseline capital and lifecycle costs

2.7 The capital and lifecycle cost implications of the above improvement scenarios were assessed in detail. The cost build-ups are provided in the appendices to this report and the cost findings are discussed in chapters 6 and 7.

Step 5: Prepare outputs matrix

2.8 The output from Steps 3 and 4 have been drawn together into a series of analysis matrices which are provided in chapters 6 and 7 of this report.

Step 6: Scenarios for alternative locations

2.9 As required by the brief, our modelling has been carried out for both urban and rural locations in order to identify any technical or cost related differences in the EcoHomes and CO ₂ improvement solutions for each. Our findings are included in chapters 6 and 7 of this report.

Step 7: Sensitivity analysis and validation exercise

2.10 A sensitivity analysis has been carried out to assess the effect of issues such as increases in fuel prices in excess of RPI. We have also validated our technical and cost findings against other similar housing based studies.

Step 8: Report and recommendations

2.11 This report and its appendices set out our detailed research methodology, workings and findings. In chapter 8 we draw out our key conclusions and provide a series of recommendations for consideration by the Scottish Government and other relevant organisations.