NHER News – rdSAP Update for Green Deal

October 26, 2011

RDSAP will be changed on 1 April 2012 throughout the UK to RDSAP 2009 v9.91. This week all EPC accreditation schemes received draft details of the planned changes; and they are so substantial that they look likely to require all DEAs to pass a ‘top up’ exam. The changes are part of a DECC/DCLG drive to gear the industry up for the Green Deal, with the EPC being the lynchpin that tells householders what measures are relevant to their home, what the likely costs are and if the measures are likely to be eligible for Green Deal funding. Regardless of the success or otherwise of the Green Deal, the changes will make RDSAP a much more useful tool containing options currently only available as part of a full SAP assessment. The changes will also make it possible to use RDSAP to reassess a dwelling previously assessed with full SAP when the dwelling was first built.

So what was the thinking behind the changes to RDSAP?

First and foremost was the need to eliminate those aspects of RDSAP that have been widely criticised and to make it a tool suitable for use in any serious attempt at improving the energy efficiency of existing homes. The view was that DEAs are now sufficiently confident, proficient and experienced to handle the increased complexity that this will require.

The starting point for improving RDSAP was that all energy efficiency / renewables measures installed into a home under the Green Deal have to be able to be entered into RDSAP software when the dwelling is reassessed for an EPC. This requirement led to over 20 areas of change to the RDSAP data entry process; for example, if the gable wall of a house has been externally clad to a U-value of 0.20 W/m2K, then RDSAP has to allow the entry of a U-value of 0.20 W/m2K for that specific wall area. This requirement led to changes being made to enable the DEA to define an alternative wall for each building part (Main, extension 1, extension 2 etc) and to be able to enter a specific wall U-value; this was then extended to allow entry of an age band or a thickness/material. Similarly, if a dwelling has a boiler fitted with a Flue Gas Heat Recovery System then the DEA needs to be able to enter such a system into the software. Although the changes to RDSAP are major, they have been designed to keep the process of assessing most homes as similar as possible to the present approach.  Much of the additional data entry will only be required when documentary evidence is available that provides supplementary information to be entered into RDSAP. And so DEAs will NOT need to calculate U-values or, in most cases, carry out additional measurements.

The second driver for change was the need for RDSAP to be able to assess and where appropriate recommend every measure that is eligible for full or part funding under the Green Deal. Therefore, added to the current list of RDSAP Recommendations will be Flat roof insulation, Room In the Roof Insulation, Floor Insulation, Insulated Doors, Waste Water Heat Recovery and Flue Gas Heat Recovery. There will be also be a section on the EPC for ‘Alternative’ Recommendations in addition to the main RDSAP recommendations: Heat pumps, micro CHP, Biomass boilers and External Insulation with cavity insulation. The look of the EPC will also be very different, containing more detailed information and less descriptive text.

The final key driver for change was the need for the estimates of financial savings to be more accurate, because of the Green Deal’s ‘promise’ that the savings under standard occupancy conditions will be more than the cost of servicing the loan taken out for the installation of improvement measures. For example, RDSAP savings will now be based upon regional weather patterns.

But what will  all this mean for DEAs in practice?

The first obvious impact will be the need to prepare for and sit the top up exam.

On the job, there will be some additional data entry to software and extra data collection. In cases there will be the need for more expert judgment; this will require clear new conventions to be agreed by all accreditation schemes. The main additions to the survey process are:

  • Entering wall thicknesses and entering separately any walls that are dry-lined
  • Establishing if there is the possibility that wall cavities are < 50mm or if the dwelling is located in a high exposure area (as these need specialist installation techniques), or if there are obvious obstructions on site that might make cavity fill or cladding more difficult
  • Entering additional data provided in documentary evidence, e.g.details of solar thermal, PV, part  walls that have been insulated
  • Checking that element areas of roof rooms are not obviously wrong; and if they are then entering better estimates
  • Assessing the approximate % of openings that are draught proofed and counting the number of doors
  • If using extended glazing, then entering the orientation of each opening
  • Recognising the presence of additional measures, e.g. flue gas heat recovery systems, waste water heat recovery systems

These changes place the EPC and with it the DEAs at the heart of government policy regarding tackling climate change and, in the long term, this has to be good for the industry. In the short term, it will require that DEAs put some time into increasing their skills and getting used to the changes. Hopefully, the way in which RDSAP 9.91 is structured and implemented will minimize the extra time needed on site. However, inevitably, there will be situations where more time is required to carry out the survey, especially when encountering new technologies and refining new processes.