Raising the Standards of Retrofit

What is PAS 2035?

PAS 2035:2019 offers an end-to-end framework for the application of energy retrofit measures to existing buildings in the UK and provides best practices for their implementation.

There are 27 million domestic buildings in the UK and the majority of them require significant energy efficiency improvements. Previous attempts to deliver retrofit measures were seen as a failure, as no universal standards or approach had been agreed upon, and several high-profile failures compounded the issue.

The result was the UK government’s 2015 commission of the Each Home Counts (ECH) review. This comprehensive review of the energy efficiency sector outlined 27 recommendations, including the establishment of a universally-recognised quality mark in the form of TrustMark.

Most significantly, the ECH review called for the establishment of an industry-wide Code of Practice, which resulted in the publication of the PAS 2035 document.

  • What does the PAS 2035 specification cover?

    PAS 2035 is a specification for what is called ‘whole-house’ or ‘whole building’ retrofit.  This is an approach to the installation of energy efficiency measures (EEMs) which takes into account the requirement of the entire building, both from a technical standpoint and considering factors like occupancy comfort.

    PAS 2035 is concerned with assessing domestic dwellings for energy retrofit. This involves identifying areas where improvements can be made and specifying and designing the relevant improvement measures. It is also concerned with the monitoring of domestic retrofit projects.

    PAS 2035 is to be used in conjunction with PAS 2030: 2019, which sets out the standards required for installing EEMs.

  • Is PAS 2035 mandatory?

    From 30th June 2021, compliance with PAS 2035 and PAS 2030 is mandatory for all companies installing Energy Efficiency Measures (EEMs), including domestic retrofit. An exemption lasting until the end of October 2021 was made for firms participating in Green Homes Grant and Local Authority Delivery Phase 1 schemes.

  • What is a PAS 2035 retrofit?

    Retrofit is the installation of additional measures to a building that weren’t included in its initial design. Much of the UK’s housing stock does not adequately offer the levels of energy efficiency and sustainability that is required if the UK is to meet its target of Net Zero emissions by 2050. Because of this, a massive programme of domestic retrofit is a major priority of the UK government.

    In the past there has been no overarching set of standards for delivering domestic retrofit. As a result, PAS 2035 was sponsored by the Department for Business, Energy and Industrial Strategy (BEIS), and designed by the British Standards Institution (BSI).

  • What is the difference between PAS 2030 and PAS 2035?

    PAS 2035 is an overarching framework for preparing plans for domestic retrofit projects in the UK. Any retrofit designs that emerge from its specifications must be installed in accordance with the requirements outlined in PAS 2030.

    PAS 2030 is a certification which businesses can achieve to demonstrate the compliance of their installations. Unlike PAS 2030, PAS 2035 is not a certification; it is a standard that sets out the specifications which compliant retrofitting must meet. Both PAS documents are to be taken as a whole and closely relate to each other.

  • What is PAS 2030: 2019?

    PAS 2030: 2019 (which replaced PAS 2030: 2017) concerns the commissioning, installation, and handover of domestic retrofit projects.

    PAS 2030: 2019 has been redeveloped to work alongside PAS 2035. Both documents should be seen as working together to create a single cohesive approach to domestic retrofit. Taken together, PAS 2030 and PAS 2035 lay down the steps all domestic retrofit projects should follow to gain compliance and ensure consumer satisfaction in accordance with the recommendations of the Each Home Counts Review.

  • What is PAS 2030 certification?

    By gaining PAS 2030: 2019 certification, retrofit installers can demonstrate that they have installed energy efficiency measures which meet the required specifications, and have delivered on customer requirements and expectations in accordance with TrustMark standards.

    PAS 2030 accreditation can help homeowners gain funding for domestic retrofit, which in turn makes your business a more attractive proposition for customers. Being PAS 2030 certified can also help you win tenders, and work on energy efficiency schemes offered by Local Authorities who often require PAS 2030 compliance.

  • The PAS 2030 certification process

    In order to become PAS 2030 certified, your business will need to demonstrate that you use a PAS-compliant Quality Management System (QMS) to ensure you have the correct processes in place to deliver consistent customer satisfaction and retrofit implementation.

    Your installers will need to have relevant qualifications and competencies; each team will require a qualified retrofit professional, and one member will need to hold an NVQ.  PAS 2030 certification requires you have up-to-date Health & Safety certification and you will also need to comply with PAS 2035 when assessing and designing retrofit plans.

    A technical assessment of one of your energy efficiency installations will need to be carried out and any compliance issues addressed before you receive certification.  An approved certification body will need to carry out the PAS 2030 assessment and certification.  For more information, visit the TrustMark website.

  • How do I get PAS 2030: 2019 accreditation?

    Built environment businesses can get PAS 2030 certified. If you are a sole trader or organisation that offers services such as plumbing, installation of boilers and heating systems, lighting units, insulation or glazing, you can apply to an approved body for certification.

  • What are the roles of PAS 2035?

    A number of professional roles are outlined in PAS 2035, including that of Retrofit Advisor, Retrofit Assessor, Retrofit Coordinator, Retrofit Designer and Retrofit Evaluator. It is not necessary that all of these roles are carried out by separate individuals, as long as whoever carries out each role has received the levels of training and certification required by PAS 2035, and that there are no unresolved conflicts of interest.

  • What is a Retrofit Coordinator?

    One of the key roles emerging from PAS 2035 is the role of the Retrofit Coordinator. Retrofit Coordinators ensure that all elements of domestic retrofit are properly managed and coordinated, and that a cohesive retrofit plan is designed and implemented. For more information on the role of the Retrofit Coordinator and how to gain the necessary training and certification, see our page on Retrofit Coordinator Training.

  • What is a Retrofit Assessor?

    The Retrofit Assessor’s role is to gather information about the building that is the subject of retrofit work. Domestic retrofit assessments are very wide-ranging and include factors such as the building’s construction, structure, and architectural features. The assessment will also consider the building’s current condition, including any structural defects, and issues such as leaks, condensation and mould build-up. Current installations such as heating and hot water, lighting, and ventilation will be documented. Any protected status, conservation restraints, or planning permission requirements will be investigated before work can begin.

    The Retrofit Assessor must also take into account information regarding the number of  building occupants and special considerations including the presence of vulnerable people, or people with disabilities.

  • What is the assessor’s role within the structure of the PAS 2035?

    PAS 2035 specifies the domestic retrofit process that must be complied with to meet its requirements. The retrofit process begins with the assessments performed by the retrofit assessor. This is the foundation of all subsequent retrofit design plans.

    In accordance with PAS 2035, the Retrofit Assessor provides their evaluation in an assessment report which may be scrutinised by the TrustMark quality assurance scheme. The work of the Retrofit Assessor is the basis on which the retrofit designer carries out their work and close cooperation is required between each role.

  • The Green Deal and PAS 2035

    In 2012, the UK government created the Green Deal, a government funded scheme which offered homeowners, landlords, and tenants a way to pay for energy efficiency measures in their homes by raising the upfront capital needed to carry them out. The loans would be repaid via the savings made in reduced utility bills as a result of the energy efficiency improvements.

    The government stopped offering financial backing for these green loans in 2015, but the loans became available again in 2017, this time backed by private investors. For installers to benefit from this funding they need to be PAS 2030 certified. In order to qualify for PAS 2030 certification, installers must show that they take a whole-house approach to delivering domestic retrofit.

  • How do I become an ECO scheme installer?

    The Energy Company Obligation (ECO) is a government energy efficiency scheme which began in 2013. Its purpose is to reduce carbon emissions and tackle the scourge of fuel poverty.

    Companies that wish to participate in the ECO scheme must be TrustMark registered via an approved body. They must also have been awarded a PAS 2030 certification by a relevant certification body, and be PAS 2035 compliant.

    The ECO scheme covers a wide range of measures, including: insulation and glazing, the installation of boilers and heating systems, and micro-generation systems such as solar panels.

    ECO measures must comply with the ECO3 Order, a set of government legislation which is administered by Ofgem.

    To find our more about PAS 2035 and PAS 2030, and what they mean for your business, contact The Retrofit Academy CIC today.


PAS 2035 Explained

We’ve created a handy document that highlights the key principles of PAS 2035 and explains what it means for you.

PAS 2035 FAQs

We get asked many questions about implementing PAS 2035.  We want to offer clarity around this complicated subject, so to help you put PAS into Practice, we’ve pulled the answers together into one easy-to-read document.

PAS 2035 Process Map

This step-by-step process map builds upon our ‘PAS 2035 Explained’ guide, which sets out what the new standards are attempting to do and how the new roles interrelate.

Ventilation Guide

We’ve created a handy guide to explain the critical role of ventilation in retrofit, which outlines the ventilation requirements of the PAS 2035 standard.

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