PAS to Passivhaus: Comparing Retrofit Standards
Introduction
As the UK moves toward its 2050 net zero target, retrofitting existing homes is a national priority. However, energy-efficient building - especially retrofit - carries risks. Poorly executed upgrades can lead to mould, condensation, and structural damage, affecting occupant health, comfort, and long-term durability.
Published: January 2026
Contents
Welcome to the Quick Guide: PAS to Passivhaus - Comparing Retrofit Standards
To address these risks, PAS 2035 provides a structured, risk-managed approach. It includes ventilation checks, moisture control, and post-installation evaluation, supported by whole-dwelling assessments that consider building condition, occupant behaviour, and measure interaction.
PAS 2035 operates within a wider compliance ecosystem, interacting with Building Regulations, British Standards, and other technical guidance. Within this landscape, Passivhaus and its retrofit counterpart EnerPHit offer a gold standard for performance and comfort. Alongside these, standards such as RdSAP (used for EPC assessments) and the AECB’s Carbonlite New Build and Retrofit Standards offer alternative frameworks for improving building performance, each with varying levels of rigour and flexibility.
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For more support on this topic view the RISE PAS to Passivhaus: Comparing Retrofit Standards Table