Potential Rating (Scotland)
Posted by Andrew Bairstow on 07-Jan-21 11:31 AM
The procedure for producing the potential rating for a buildings EPC can be flexible and fit in with your workflow. The process of identifying suitable recommendations for the building and the Potential rating are directly related and so it makes sense to test the effect of recommendations by running calculations with the relevant data changes. Note that many NCM recommendations are imprecise and thus DesignBuilder cannot advise how these should be implemented. Note that up to three user recommendations (with shortest payback) are included in the recommendations report and thus these could be used for precise changes used for generating the potential rating.

You must start the process with a model which has been QA tested. If errors are identified in the subsequent process then it will be necessary to repeat much of the process.

Note the calculation has two Building model cases:
  1. Actual
  2. Potential (not available in DSM)

It is not essential that the Potential setting is used to generate the Potential Rating it is just a mechanism to facilitate separating the calculation for Actual and Potential buildings and for locking the Actual Rating whilst you generate the Potential rating. Once the Potential rating has been established then the EPC must be generated:

  1. In the model containing the existing building specification
  2. With Building Model case = Actual
  3. With the potential rating assigned in the dialogue

Example Workflow
  1. QA check the EPC model
  2. Save the QA'd model as ProjectName_ACT.
  3. Copy this model to ProjectName_POT.
  4. Open ProjectName_POT and run the ACTUAL calculation

5. Switch the model case in the calculate window to POTENTIAL and run the model again, the EPC now shows two flags showing both Actual and Potential ratings the same.

6. Use summary outputs to help establish weaknesses in the building specification and identify possible ways of improving these
7. Test your ideas noting that three user recommendations can be added
8. Establish the most appropriate recommendations and save ProjectName_POT with them implemented in the model. Record the resulting Potential Rating.

9.   QA check the Potential model.
10. Open ProjectName_ACT, enter the recommendations and the Potential Rating then run the calculation.
11. For DSM calculations tick the box 'Update Improvements in EPCGen input': this will amend the EPC input file rather than rerunning the calculation.