PAS 2035 explained

Flummoxed by PAS 2035 and how it affects your business? Read our handy guide to bring you up to speed.

What is PAS 2035?

Simply put, PAS 2035 is a framework to follow for the energy retrofit of domestic buildings.

It details best practice guidance for domestic retrofit projects and delivers a ‘whole- house’ or ‘whole building’ approach which considers:

  • Occupants and end users
  • Each home individually (including construction)
  • Complete oversight of assessment, design, delivery, and use.

This resolves the problems of retrofit measures being considered in isolation, as identified in the government’s ‘Each Home Counts’ review, which may accidently damage building energy efficiency overall.

How will PAS 2035 change your ways of working

Don’t be wrong-footed. Learn the steps in the process of retrofitting a dwelling with energy efficiency (this is set out in the PAS 2035 document standard), which are summarised below.

Step 1. Preliminaries

The first step for all new projects is to set out the client preliminaries – what the client wishes to achieve from the project and the overarching brief for the retrofit project. This can include items such as improving the EPC rating, improving resident comfort, and reducing fuel bills.

Step 2. Risk assessment

The risk assessment stage is to collate triage data which considers the risk of the retrofit project. This determines factors such as the difficulty of the retrofit, the number of properties in the retrofit and the ages and construction type of the dwelling as far as risk is concerned. This provides a project risk path (A, B or C) for the rest of the retrofit co-ordination and design.

Step 3. Whole dwelling assessment

This is the first involvement of the Retrofit Assessor, who will be responsible for collating data on the performance of the dwelling and what the proposed performance of the dwelling could be.

This includes items such as understanding the properties heritage construction dimensions, current services, defects, existing constraints, U values, moisture and suitability for improvement, occupant appraisal and use of the dwelling, ventilation review, air permeability assessment, fuel consumption and if a traditional dwelling a heritage significance statement. The information is assessed to provide an output for improvement under a retrofit design.

Following on from the assessment, the retrofit coordinator works with the retrofit assessor to provide a medium term retrofit plan.

Step 4. Retrofit design

The retrofit design stage takes the assessment and builds this up to a workable construction stage design. This takes an in depth look at the dwelling performance and what Is required to adequately retrofit to avoid any issues and provide a ‘no regrets’ strategy. During this stage, the Retrofit Assessor is retained in case further information is required and the Retrofit Coordinator has full oversight to ensure the design covers the salient points that are raised during the risk assessment stage.

Step 5. Installation

Following on from the retrofit design which includes procurement exercises and ensuring a warmup process for the installer, the Retrofit Coordinator oversees the installation of the retrofit in accordance with PAS 2030. PAS 2030 is the framework and procedure for installation of retrofit measures as opposed to the oversight of installation which is PAS 2035.

Step 6. Testing and commissioning

The testing and commissioning period is the responsibility of the Retrofit Installer, however, the Retrofit Coordinator oversees the testing of all installed measures by the Retrofit Installer and ensures that adequate certification and commissioning data is provided as part of this process.

Step 7. Handover

The handover process is much the same as the process for general contract administrator and employer’s agent roles. The Retrofit Coordinator ensures that full health and safety files and O&M instructions are handed over to the client and end user for an understanding of use of the dwelling. During this period new energy performance certificates and any data is also recorded with TrustMark (or similar) for future information on retrofit.

Step 8. Retrofit advice

The retrofit advice stage is not just specific to this stage as retrofit advice is provided throughout the project. However, the retrofit advice stage is for the end user to fully understand the installation that is taking place. It is an opportunity for the Retrofit Advisor to provide clear, concise and laymen’s term knowledge to the end user – ensuring there are no issues being created with a lack of communication or information from the installer – enabling the occupant to get the most out of the building.

Step 9. Monitoring and evaluation

The monitoring and evaluation stage collates data from the end user. Firstly, it ensures the retrofit project has been a success and is working within the parameters of both the assessment and the design as expected, and secondly it ensures that the advice provided is being followed by the occupant.

There are several monitoring and evaluation techniques that range from simple survey data, in-depth intrusive data gathering to inspections opening up and monitoring of controls.

Step 10. Claims of compliance

Claims of compliance is a specific step at the end of the monitoring and evaluation stage where all the data for the retrofit installation design assessment and use is gathered and passed along to the quality assurance body.

There are three main routes of claims of compliance:

  • Independent third-party certification from a UCAS accredited body
  • Other party validation (where a third-party body is appointed)
  • Self-assessment (where the Retrofit Coordinator uploads evidence of compliance in accordance with PAS 2035).

Step 11. Qualifications

Qualifications is covered throughout the document, however, has a specific section at the end of PAS 2035. It covers any conflict of interest and assurance that each retrofit role is fulfilled by an adequately qualified person.

Who’s who in the world of retrofit

The main professional roles for PAS 2035 are:

The Retrofit Advisor 

The Retrofit Advisor provides advice to both the client and end user in terms of what may work in terms of retrofit and how to use the retrofit once the work is undertaken. This advice should be straight forward and easy to understand, also non-technical were possible to ensure the greatest understanding across clients and end users.

The Retrofit Assessor 

The Retrofit Assessor provides an in-depth assessment of the current arrangement and build of the property and how it may be improved using collated data from several different outlets including surveys and visits.

The Retrofit Coordinator

This is an end-to-end role with full responsibility for demonstrating compliance with PAS 2035. Considered the primary role as they have full oversight of both the installation and handover phases, working alongside the installer.

The Retrofit Designer

The Retrofit Designer develops the assessment and the median term retrofit strategy to provide a fully compliant retrofit design. This is also overseen by the Retrofit Coordinator to ensure that the requirements of the risk assessment and the retrofit assessment are both met.

The Retrofit Installer

The Retrofit Installer is a contractor who installs the retrofit measures specified in accordance with PAS 2030.

The Retrofit Evaluator

The Retrofit Evaluator carries out monitoring and evaluations post fit-out of the retrofit. This can include data gathering or can be in-depth analysis of data using a number of control monitors and intrusive survey works.

Is it mandatory?

PAS 2035 is not mandatory for all retrofits, but since 20 June 2021, PAS 2035 compliance has been a requirement for any publicly funded retrofit projects.

Although it is not strictly needed for non-funded projects, it is recommended that the framework is used for any residential retrofit projects as it provides a clear path to compliance and best practice for the assessment, design, installation and monitoring of energy efficient measures.

Next steps

Now you’re up to speed, get in touch to find out how we can help your business. We have a dedicated team who can help put PAS 2035 into practice.

Your contacts are:

London office
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