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Retrofit Assessment
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Are you looking for a Retrofit Assessment?
A Retrofit Assessment is a bespoke survey report carried out by PAS 2035 Retrofit Assessors. A site inspection of homes aims to collect lots of data about the property to inform condition, energy performance and occupancy of the home. They pass data on tor Retrofit Coordinators and Designers to help inform their plans.
Do you require a Retrofit Assessment?
PAS2035:2023 Compliant Inspections
PAS 2035 is essentially a risk management tool; it is designed to reduce the risk of technical failures on the project. Another way of looking at it is quality management. It is about delivering a quality retrofit that meets the customer’s expectations.
The appropriate amount of work involved at each stage of the project, as well as the required level of knowledge and experience of the project team, is determined by the assessed level of project risk. So this initial risk assessment is a key step.
The dwelling assessment is the responsibility of the Retrofit Assessor and is usually referred to as the retrofit assessment. The PAS 2035 dwelling assessment is specific to the customer and includes an occupancy assessment. The scope of the retrofit assessment is ‘whole-house’ and requires an evaluation of factors as such as the dwellings discussed in great detail in the below sections.
Context and Site Setting
In a retrofit assessment, site context refers to the environmental and geographical factors that influence how a property performs and how suitable different retrofit measures will be. It includes exposure to wind and driving rain, flood risk, local microclimate, shading, and the relationship between the property and surrounding buildings. It also considers planning constraints, heritage designations, access limitations, and the typical construction character of the area. Understanding the site context ensures that recommendations are safe, compatible with the building fabric, and aligned with PAS 2035 requirements.
Before attending site, the assessor completes structured desktop research to build a clear picture of the property and its surroundings. This typically involves reviewing aerial imagery and mapping, checking planning and building‑control records, analysing environmental datasets (flooding, radon, soil conditions), and examining local housing archetypes and historic land use. The aim is to identify risks, constraints, and opportunities early, allowing the on‑site survey to be more focused and ensuring that any proposed retrofit measures are evidence‑based and appropriate for the dwelling
On-site Inspection of Condition
The on‑site inspection is a structured, fabric‑first assessment of the property’s physical condition. Its purpose is to understand how the building is performing in reality, identify defects that influence heat loss or moisture movement, and determine how suitable different retrofit measures will be. The assessor examines the construction type, age, and overall integrity of the building fabric, including walls, roofs, floors, windows, doors, and junctions. Particular attention is given to signs of damp, ventilation issues, thermal bridging, insulation quality, and any structural or safety concerns that may affect retrofit design.
During the visit, the assessor also reviews heating and hot‑water systems, ventilation arrangements, airtightness characteristics, and the presence of previous alterations or extensions. Photographs, measurements, and diagnostic observations are recorded to build an evidence‑based picture of the dwelling’s condition. This ensures that any proposed retrofit measures are compatible with the existing fabric, minimise risk, and support long‑term building performance in line with PAS 2035 principles.
Ventilation Assessment
A ventilation assessment examines how air moves through the property and whether the existing arrangements provide safe, effective moisture management. The assessor reviews both purpose‑provided ventilation (extract fans, trickle vents, passive vents, MVHR systems) and adventitious ventilation such as gaps, chimneys, and uncontrolled air leakage. The aim is to understand how well the dwelling removes moisture, pollutants, and stale air, and whether current ventilation levels are adequate for the occupancy and building type.
During the inspection, the assessor checks the condition and performance of extract fans, identifies areas of poor air circulation, and looks for evidence of condensation, mould, or high humidity that may indicate ventilation imbalance. Airflow pathways, room‑by‑room ventilation provision, and the interaction between airtightness and moisture loads are all considered. This ensures that any proposed retrofit measures—particularly those that improve airtightness or insulation—are supported by a safe, compliant ventilation strategy in line with PAS 2035 and Building Regulations.
Occupancy Assessment
The occupancy assessment examines how the people living in the property use energy, ventilation, heating, and hot water on a day‑to‑day basis. Its purpose is to understand the household’s routines, comfort expectations, moisture‑generating activities, and any behaviours that influence indoor environmental conditions. This helps identify whether issues such as condensation, mould, or high energy use are driven by the building fabric, the way the home is used, or a combination of both.
During the assessment, the assessor gathers information on heating patterns, thermostat settings, ventilation habits, appliance use, hot‑water demand, and the number of occupants. They also consider any vulnerabilities, accessibility needs, or comfort concerns that may affect the suitability of certain retrofit measures. This ensures that recommendations are not only technically appropriate but also practical, safe, and aligned with how the household actually lives in the home.
Energy Performance Report
The energy performance report provides a clear, evidence‑based overview of how the property currently uses and loses energy. It brings together data from the on‑site survey, occupancy assessment, and desktop research to identify the key factors influencing heating demand, heat loss, ventilation balance, and overall efficiency. The report outlines the building’s construction, insulation levels, glazing type, heating and hot‑water systems, and any areas where energy performance is being compromised by defects, poor ventilation, or outdated services.
Using this information, the assessor produces a structured analysis of the dwelling’s thermal performance, including estimated heat‑loss pathways, system efficiency, and opportunities for improvement. The report highlights priority measures, potential risks, and the expected impact of different retrofit options, ensuring that recommendations are technically sound, fabric‑led, and aligned with PAS 2035. This forms the foundation for a safe, practical, and cost‑effective whole‑house retrofit plan