Guidance Standard Tool

Assured Performance Process (APP)

What is the Assured Performance Process (APP)?

There is often a huge difference between how buildings are supposed to perform, and how they actually do.  The assured performance process provides independent and expert input to the development process to minimise this energy, overheating, and indoor air quality performance gap.  As well as helping to reduce carbon emissions and climate change, this improves the health of people using buildings.

The Assured Performance Process TM (APP) maps to the RIBA Plan of Work and has five stages of expert, impartial review and assessment. APP assessors are accredited by The National Energy Foundation for their expertise and they offer two services:

  • APP implementation across all five key stages – supporting the client throughout the development process. This is a bespoke service.
  • One off reviews tailored to the stage of the development

Who is behind APP?

The Good Homes Alliance has secured a two year license for the Assured Performance Process (APP) from the original developer and owner, the National Energy Foundation (NEF).

NEF is a charity which has been meeting its mission of “improving the use of energy in buildings” for more than 20 years.  NEF has established other nationally recognised quality systems.

Contact Julian Brooks at to find out more.

Research findings

EPCs as efficiency targets

Many organisations and local authorities are searching for a way to measure their progress towards a net zero built environment.  In the domestic sector, every home has an Energy Performance Certificate (EPC) which gives an Energy Efficiency Rating between 1 and 100.  It might therefore seem like a good idea to use the EPC rating as a metric to drive lower emissions in both existing and new housing.

However, the EPC mechanism and its supporting calculation isn’t designed to do this and, furthermore, has failed to keep pace with a rapidly decarbonising grid.  As of 2020, electricity emissions are 30% less than those associated with gas.  But the EPC calculation still assumes that electricity produces more than twice the level of emissions. EPCs are also designed to be compliance tools which means that the supporting calculation has some necessary assumptions and limitations. The result is that using the EPC rating alone to try and drive energy efficiency is unlikely to have any effect.

To illustrate why, and to suggest an alternative, the Passivhaus Trust has produced a short paper which sets out how EPCs work, their limitations and what alternatives might produce better results.

Author: Passivhaus Trust

Publication date: April 2020



Closing the Gap Between Designed and As Built Performance

In recent years, the housebuilding industry and government have grown increasingly concerned over the potential gap between design and as-built energy performance. It could undermine a building’s vital role in delivering the national carbon reduction plan, present a reputational risk to the housebuilding industry and damage consumer confidence if energy bills are higher than anticipated.

In response, the Zero Carbon Hub was commissioned to review evidence for the significance of this gap, explore potential reasons for it and set out proposals to address these reasons.

The project has engaged more than 160 industry experts from across 90 companies, seeking to understand the nature of the Performance Gap and provide solutions.

End of Term report (July 2014)




Evidence Review report (March 2014)



Interim Progress report (July 2013)



Author: Zero Carbon Hub

Publication date: July 2013-July 2014

Case Study Report Research findings

GHA Monitoring Programme

Phase 1

This report provides an overview of the findings, observations and recommendations resulting from Phase 1 of the Good Homes Alliance (GHA) monitoring programme. Phase 1 is based on post-construction testing of a series of new-build residential projects, across a range of construction types.

This project was funded by DCLG, EST and NHBC Foundation.


Phase 2

This document focuses on the key results of the Phase 2 Post-Occupation Evaluation and compares the findings of the in-use performance data from the houses in terms of energy and water consumption and Indoor Air Quality (IAQ), the performance of installed building services, and occupant behaviour/ perceptions.

This project was funded by DCLG, EST and NHBC Foundation.


Case studies

The following projects were used as case studies for the research:

Old Apple Store, Stawell




One Brighton