What is a PAS 2035 Retrofit Assessment and Why is it Required?
If you are looking into the Warm Homes Plan, you will quickly come across the term PAS 2035. It is a mandatory part of the process and applies to all funded retrofits, regardless of which funding route is used. Understanding what it involves will help you know what to expect.
What is PAS 2035?
PAS 2035 is a publicly available specification published by the British Standards Institution. It sets out the framework for assessing and designing energy efficiency improvements in domestic buildings. It was introduced following a review of earlier retrofit schemes, some of which had caused problems by installing improvements without properly understanding the properties they were being fitted to.
The standard applies to all publicly funded domestic retrofit work in England, including Warm Homes Plan projects. It is designed to ensure that improvements are appropriate, safe, and effective.
What does a retrofit assessment involve?
A PAS 2035 Retrofit Assessment is carried out by an accredited Retrofit Assessor. The assessor visits the property and surveys it in detail, looking at:
- The construction type and age of the building
- Existing insulation levels in the walls, roof, and floor
- The heating system, including boiler type, age, and controls
- Ventilation: how air moves through the building
- Moisture and damp: whether there are existing issues that could be made worse by certain improvements
- Windows, doors, and draughtproofing
The assessor uses this information to produce an Improvement Measures Report. This document sets out which energy efficiency measures are appropriate for the property, and critically, the order in which they should be carried out.
Why does the sequencing of improvements matter?
This is one of the key reasons PAS 2035 exists. Energy efficiency improvements interact with each other and with the building itself. Doing them in the wrong order, or installing them without understanding the property, can cause serious problems.
For example: adding insulation to a poorly ventilated property can trap moisture and cause condensation, mould, and damp. In some cases, improvements installed without proper assessment have caused structural damage and health problems for occupants. The PAS 2035 standard is designed to prevent this by requiring a proper survey before any work begins.
The Improvement Measures Report will set out a sequenced plan. In some cases, ventilation improvements need to be made before insulation is added. In others, certain measures may be ruled out altogether because of the property's construction or condition.
Who carries out a retrofit assessment?
Retrofit Assessors must be accredited under a recognised scheme. Accreditation bodies include ECMK, Stroma, and others. The assessor must hold a current qualification and be registered with an approved body.
The Retrofit Assessor is separate from the Retrofit Coordinator, who oversees the design and management of the improvement works once the assessment is complete. Both roles are required under PAS 2035 for funded retrofit projects.
Do you have to pay for the assessment?
For Warm Homes Plan funded projects, the cost of the retrofit assessment is typically covered as part of the scheme. You should not generally be asked to pay for it upfront. However, the specifics depend on how your local borough council administers its allocation.
How long does it take?
The site visit itself typically takes one to two hours for a standard domestic property. The assessor will then produce the Improvement Measures Report, which can take a few days. Once the report is complete, the Retrofit Coordinator uses it to design the improvement package and arrange the works.