If you have looked into home energy improvements or retrofit work in the UK, you will almost certainly have encountered the term PAS 2035. But what exactly is it, why was it introduced, and how does it affect homeowners and landlords? In this guide, we explain everything you need to know about this important standard and its role in the UK retrofit landscape.
What is PAS 2035?
PAS 2035 is a publicly available specification (PAS) published by the British Standards Institution (BSI). It sets out the framework for retrofitting homes to improve their energy efficiency, and it applies to all government-funded domestic retrofit projects in England, Scotland, and Wales. The standard was introduced to ensure that energy efficiency measures are designed and installed in a coordinated, whole-building approach rather than as isolated individual measures.
Before PAS 2035, it was common for individual measures — such as wall insulation or a new boiler — to be installed without considering how they interacted with the rest of the building. This sometimes led to unintended consequences such as poor ventilation, condensation, or damp. PAS 2035 addresses this by requiring a holistic assessment of each property before any work begins.
The Key Roles in PAS 2035
PAS 2035 defines several professional roles that must be involved in a compliant retrofit project. The Retrofit Assessor conducts a detailed survey of the property, collecting data on the building fabric, heating system, ventilation, and occupant behaviour. The Retrofit Coordinator then uses this data to develop a medium-term improvement plan, specifying which measures should be installed and in what order. The Retrofit Designer creates the detailed technical designs, and the Retrofit Installer carries out the physical work to PAS 2030 standards.
This structured approach ensures that every decision is informed by a thorough understanding of the property and that measures are properly coordinated. For example, if a property is having external wall insulation installed, the Retrofit Coordinator will also assess ventilation requirements to ensure the airtightness improvements do not lead to moisture problems.
Why Does PAS 2035 Matter for Homeowners?
For homeowners accessing government-funded improvements through schemes such as HUG2, GBIS, or SHDF, PAS 2035 compliance is mandatory. This means that the company delivering the work must follow the PAS 2035 process. As a homeowner, this gives you confidence that the improvements to your home have been properly designed and will deliver the expected energy savings without causing unintended problems.
PAS 2035 also requires proper documentation and quality assurance throughout the project. Each property has a data management system that records all assessments, designs, and installation details. This creates a permanent record of the work carried out, which is valuable for future maintenance, further improvements, or when selling the property.
PAS 2030 vs PAS 2035
PAS 2030 and PAS 2035 are companion standards that work together. PAS 2035 covers the overall retrofit process — assessment, design, and coordination. PAS 2030 covers the installation of individual energy efficiency measures, setting the quality standards that installers must meet when fitting insulation, heating systems, and other measures. Think of PAS 2035 as the strategic plan and PAS 2030 as the quality standard for execution.
How Bright Nest Energy Applies PAS 2035
At Bright Nest Energy, PAS 2035 compliance is embedded in everything we do. Our qualified Retrofit Assessors and Coordinators follow the full PAS 2035 process on every funded project, ensuring your home improvements are properly designed, coordinated, and delivered. Our Technical Director, Aneesh Abraham MCIOB, oversees compliance across all projects to ensure the highest standards are maintained.
Need PAS 2035 Compliant Retrofit Work?
Bright Nest Energy delivers fully compliant retrofit projects under all major funding schemes.
Speak to Our Team