Hopefully, all domestic energy assessors will by now be aware that the government are embarking upona programme of change for domestic energy assessments in England (the other administrations are alsodeveloping their own similar plans).
These changes are intended to:
1. Improve the accuracy and reliability of EPC assessments and associated recommendations;
2. Improve the quality of collected evidence and, in turn, of the assessments being completed;
3. Account for developments in best practice and the technologies available;
4. Promote further improvements to the energy efficiency of homes in the future;
5. Reduce the carbon footprint of homes in the future; and
6. Allow the use of EPCs for a wider range of purposes including ensuring that they better supportgovernment initiatives and objectives.
To achieve this, there are a number of initiatives underway, and changes planned that will affect allenergy assessors, particularly those working in the domestic sector. The ultimate objective is theintroduction of the new Future Homes Standard and accompanying Home Energy Model (HEM) due nextyear. This project is developing well and at pace with the first public consultation now completed. Inthe meantime, the long delayed introduction of RdSAP 10 is now expected this summer (date still to beconfirmed).We are aware that some accreditation schemes and training organisations have already been providingupdates for the introduction of RdSAP 10. However, we have made a conscious decision not to embarkon this prior to this update as many details were yet to be confirmed. It has been our intent to avoidcontradictory advice by waiting until we are at a point where we can release confirmed details forassessors to implement.
Take action now!
Whilst some aspects of RdSAP 10 are still in development (including the actual assessment software),we are now at a point where many of the details have been confirmed. We also believe that we are nowat a point where all Domestic Energy Assessors (DEAs) need to take action to ensure that they are readyfor the changes ahead.
What is changing in RdSAP 10?
RdSAP 10 includes numerous changes, many of which will occur behind the scenes in the calculationengine. However, there are some major changes that will require the collection of additional evidencebeyond that which is routinely collected at the moment. These are complemented by a number of othersignificant changes that will impact the way an assessment is calculated, and the ratings produced.The current engine of RdSAP 10 awaiting implementation is RdSAP 10.2.
Major changes requiring the collection of new data:
• Window measurements required for all windows.
• Location of each window allocated to main walls or each extension, or alternative walls.
• Window shutters added as a new feature.
• Room in roof (RR) revised to take into the account all elements including continuous main wall.This includes new measuring requirements.
• PV Diverter for water heating added.
• PV Batteries added.
• An accredited air pressure test (Air Tightness Testing) result can be used if available.
•Small scale hydro added as in SAP10.2.
Significant changes compared to RdSAP2012 specification include:
• Thermal properties of insulation revised.
• Roof insulation details have more options.
• Floor insulation revised; heated basement details added.
• Table of Window U-Values expanded.
• U-values of brick wall revised to account for wall thickness.
• U-values of stone walls revised.
• Curtain wall added as a new wall type.
• Hot water tank size included.
• Hot water tank insulation included.
• Additional alternative/sheltered wall added.
• Mechanical ventilation is treated as in full SAP allowing PCDB entry, still allowing default values.
• PV calculated as in SAP10.2.
• Ventilation algorithm allows more options.
• New age-band M added, and all tables of U-values updated.
• Data for Isle of Man added for completeness of information.
• Table 32 with the RdSAP10-specific fuel prices replaces fuel prices in Table 12 of SAP10.2.
• RdSAP10-specific metrics added to replace SAP metrics in SAP10.2.
• Flue gas heat recovery - calculation according to SAP 10.2.
• Waste water heat recovery - calculation according to SAP 10.2.
• Heat pumps - Calculation according to SAP 10.2.
Additionally, there are a number of changes to the recommendations produced and the factors thattrigger them. These include:
• Improved U-values revised for all building elements.
• Measure to insulate party wall removed.
• Order of measures for Northern Ireland removed.
• Air and ground source heat pumps are no longer alternative measures.
• PV battery and PV diverters added.
What are the RdSAP 10 Data requirements?
A full list of all the data inputs required to complete an assessment using RdSAP 10 is provided in Table31 of the RdSAP 10 Specification. This table also provides some clarification as to the meaning of some terms.
Much of the data collection remains the same as the current assessment process. However, there aresome very significant changes and assessors are advised that they should expect site surveys to takesignificantly longer they the current assessment methodology.Significant changes include:
• Windows: Full details of all windows (including roof windows) must be recorded. For each, thisincludes the dimension of the opening (measured to 0.01m or better), type of frame, type ofglazing, glazing gap, window age, the window orientation, whether or not is has fixed shutters,type of shutter, whether the window is draught proofed and the building part that it is within. Ifspecific specifications are available (e.g. u-values, g-values etc) these must also be evidencedon a window by window basis. This may be achieved using either a window schedule or byrecording the relevant information on a detailed floor plan. NB: Windows within a non-separatedconservatory must be measured but those in a separated conservatory may be ignored.
• Roof Rooms: Roof rooms are now treated differently depending upon the type and constructionelements present. Construction elements include any common wall within the roof room, gablewalls, party walls, sheltered walls, common walls, sloping ceilings and flat ceilings. For thepurposes of site data collection, the following details will need to be recorded for eachconstruction element separately:
▪ The construction type / method;
▪ Any insulation present that can be evidenced;
▪ The length and height of the element (measured to 0.01m or better) to enable the areato be calculated.
Additionally, the floor area of the room will also still need to be recorded.
• Environmental Technologies: Where environmental technologies are present (e.g. PVdiverters, PV batteries, hydro generators etc.) there presence should be recorded and evidencedincluding serial and product numbers where possible. Specifications for the systems shouldalso be collected where possible.
• Air Tightness: Where testing has been undertaken, details and a copy of the accredited resultshould be obtained.
• Building Orientation: The building orientation, context and location is now of great significanceand will need to be evidenced as part of every assessment. We expect that a suitable aerialphotograph (e.g. from Google Earth) be supplied for each assessment which clearly identifiesthe building being assessed and its orientation. Non-domestic assessors will already be familiarwith this requirement.
• Smart Meters: Recording the presence of smart meters and the fuels they serve.
Why do I need to take action now?
It is not expected that there will be an overlap of methodologies. A date will be set from which alllodgements will need to use the RdSAP 10 methodology and lodgements using the current system are not expected to then be possible. Whilst there will be advance warning of this date, we have observedthat the notice period is likely to be less than the typical period between site survey and lodgementcurrently used by a significant number of assessors lodging with us. Furthermore, should any lodgedassessments fail audit and require replacement, this may have to be completed using the newmethodology and so will require the additional data inputs to be available.
To be clear, failure to ensure that all the evidence and data required for an RdSAP 10 assessment iscollected now may result in it becoming necessary for you to revisit the site again in the near future.
All assessors are also reminded that it is best practice to ensure that all assessments are lodged assoon as possible following a site visit, typically within 48 hours for a domestic EPC using the RdSAP methodology.
Mike Gordon
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