PAS 2035: Retrofitting dwellings for improved energy efficiency

What is PAS 2035?

PAS 2035: The New Publicly Available Specification that lays out all retrofit energy efficient enhancements to the UK’s existing housing stock.

PAS 2035 is the over-arching document in the retrofit standards framework. Within this framework, TrustMark holders will be required to comply with this standard when carrying out any domestic retrofit work. All the other standards referred to in this PAS are also part of the retrofit standards framework.

Statutory national targets suggest that to combat the threat of climate change, a substantial reduction of greenhouse gas emissions needs to be made. To ensure this happens, significant improvements must be made to the energy efficiency of the UK’s building stock, specifically the vast majority of its 27 million domestic buildings.

PAS 2035 supports work towards achieving this and the Near Zero Energy Buildings (NZEBs) target in-line with new EU objectives.

To achieve these targets, this PAS works towards the objective by championing technically sound and responsible domestic retrofit work. This includes the improved functionality and durability of buildings, as well as improved energy efficiency, reduced environmental impacts of buildings, and by minimising the performance gap that occurs due to the shortfall of perceived reductions in fuel use, fuel cost and carbon dioxide emissions.

PAS 2035 comprises the following main elements

The Retrofit Assessor

Undertakes an assessment based on the following criteria; an Occupancy Assessment, an Energy Assessment and a Condition assessment of the property. These elements will form sufficient data to allow the Retrofit Coordinator to outline a Medium-Term Improvement Plan for the domestic property in question.

The Retrofit Coordinator

The Retrofit Coordinator forms the fulcrum of the Retrofit process. By gathering the data collected by the Retrofit Assessor, the Coordinator will build and draw-up the Medium-Term improvement plan which will span a period of 25 years. Before any retrofit installation work can commence, the Coordinator must be confident that all condition related reports are appropriate to the building in question and, crucially, of good accuracy. It is also the Retrofit Coordinator’s responsibility to arrange the design of the measures outlined in the Assessor’s report and to commission the installer to carry out the work. Throughout this process the Coordinator will act in the best interests of the domestic property’s owners.

Retrofit Designers & Advisors

Retrofit Designers will undertake the design improvement element of the process, especially those that concern junctions that comprise multiple improvement functions. Retrofit Advisors will deliver face-to-face advice to homeowners, throughout the retrofit process, this will include potential alterations to improve energy consumption and any other factors that may be necessary.

Training Courses

Stroma Certification is delivering a range of training courses and schemes in-line with the release of the new standard framework.

PAS2035 Retrofit Assessor Online Training

Face to face real-time remote training with tutor. Interact with the trainer and other course candidates, ask questions and get immediate answers. Undertake an online virtual survey with the course trainer. View Course.

Retrofit Assessor Training

Stroma Certification’s Retrofit Assessor Training is designed to upskill qualified DEA/GDAs to undertake retrofit assessments in accordance with the new standard framework; the specification for the energy retrofit of domestic buildings. Every dwelling that is to be subjected to energy retrofit work must first be assessed by a Retrofit Assessor. Their main role is to provide information to the retrofit coordinator about the dwelling. This information will subsequently be used by the Retrofit Designer to determine the best package of measures for the building.

A Retrofit Assessor is a person who has been trained and is competent in accordance with PAS 2035.

A final multi-choice exam will be completed on day 2 of the training, re-sits can be taken on the same day.

View Course.

Certification Schemes

Retrofit Assessor Certification Scheme

Upon completion of the Retrofit Assessor training, candidates will be eligible to join Stroma’s TrustMark approved Retrofit Assessor Certification Scheme and become certified to carry out and lodge Retrofit Assessment Reports.

Stroma Certification’s Retrofit Assessor Scheme will operate in-line with PAS 2035. The scheme will ultimately deliver training and CPD geared towards a fully-fledged Retrofit Assessor Role, in which a Domestic Energy Assessor (DEA) will be authorized to carry out a retrofit assessment.

A retrofit assessment will enable a non-intrusive on-site assessment to take place which will allow a retrofit coordinator to carry out a Medium Term Improvement Plan, based on evidence gathered from the assessment, within the requirements of the nwe standard framework.

Stroma Certification will allow Retrofit Coordinators who are working towards their Diploma to join the scheme. It has been agreed that the following criteria is applied by Stroma Certification:

  • 9 of the 12 modules have been completed and passed (75% completion)
  • Passing the modules is confirmed with the relevant training provider - evidence of completed modules is required
  • Completing and being awarded the Diploma is strictly time-bound to 3 months from the point of registration

Retrofit Coordinator Scheme

Stroma Certification is working closely with the Retrofit Academy to deliver a Retrofit Coordinator Scheme. We are offering a training course, delivered by the Retrofit Academy, which will upskill existing DEAs to manage domestic retrofit work, this Level 5 qualification will work alongside the Stroma Retrofit Coordinator Certification. Together they form the basis of the crucial role of Retrofit Coordinator, which is a mandatory requirement on all domestic retrofit projects, under the new PAS 2035 framework.

This new scheme will enable already qualified DEAs to undertake Retrofit Coordinator work, which is expected to be in high demand, as the standard becomes more prevalent. As well as this, the government’s plans to make the UK carbon neutral by 2050 will ensure that all PAS 2035 accredited professionals become at the forefront of the energy industry’s push to make existing homes more sustainable.


Our in-house software development team is monitoring the software requirements for retrofit assessments. The PAS 2035 software offer from Stroma will utilise our existing award-winning platforms, RSAP+ and FSAP to support compliant collection of EPC and OA data. RSAP+ is an essential tool for energy assessors, ensuring that assessors can calculate and lodge across all devises, as part of the software’s bespoke package, this tool will be increasingly useful when applied to domestic retrofit work because of its cross-platform functionality. In addition, our FSAP software is the most advanced in the industry, enabling energy assessors to complete SAP assessments on a range of properties.

Professional Indemnity Insurance from Thomas Carroll

Whether you’re a Retrofit Coordinator or Assessor, Thomas Carroll offers Professional Indemnity Insurance for your role in PAS 2035.

For advice or a quote for a tailored annual insurance policy, please get in contact with Stephanie Williams at Thomas Carroll Brokers at

Public Liability Insurance cover is also available – discuss your insurance requirements today.