At PB Sustainability Ltd, we provide fully compliant Psi-value calculations to help improve your SAP rating, reduce heat loss, and support compliance with the latest UK Building Regulations.

Psi-Value (or Ψ-Value) represents the difference in thermal performance between a junction and the surrounding building element. It can be either positive or negative, depending on the detailing. Junctions can account for over 20% of total heat loss through a building’s fabric, making accurate calculations essential for thermal efficiency and compliance.

With the introduction of SAP10 and the removal of Accredited Construction Details (ACDs), relying on default values can lead to significant thermal bridging penalties — which negatively impact your Design Fabric Energy Efficiency (DFEE) score and may increase construction costs.

Our tailored Psi-value assessments model the actual heat loss at key junctions in your design. This helps reduce excessive thermal bridging, improve overall energy performance, and ensure your project meets current expectations for sustainability and compliance.

Why Choose PB Sustainability?

• Bespoke advice based on your specific design and build method
• Full calculations, reporting, and expert support in one clear quotation
• Trusted by energy consultants, architects, and housing providers across the UK
• Delivered by qualified professionals with a proven record of delivering cost-effective solutions
• Reports suitable for SAP submissions and Code for Sustainable Homes compliance
   

Need thermal bridging calculations for your project?
Speak to our energy specialists today and get practical, accurate support from start to finish.