Enhancing Energy Efficiency with Bespoke Thermal Bridging Calculations

Understanding Thermal Bridging (PSI-Values)

Thermal bridging has become increasingly significant in the construction industry. As the demand for energy-efficient homes grows, thermal bridging is recognized for its impact, potentially accounting for up to 30% of a building’s total heat loss. This shift is driven by evolving legislation and a focus on architectural detailing and construction practices.

Benefits of Thermal Bridging Calculations

• Minimise heat losses
• Reduce unwanted heat gains
• Lower energy consumption
• Create a more sustainable and comfortable living environment
• Improve your SAP Rating
• Prevent cold spots and reduce condensation risks

What is a PSI-Value?

A Psi value (Ψ) measures heat transfer through specific parts of a structure prone to thermal bridging. It indicates the additional heat lost in these areas compared to the main insulation. Lower Psi values are preferred as they signify better energy efficiency and warmth.

PSI-Value in SAP

The Standard Assessment Procedure (SAP) is the official method for evaluating the energy performance of dwellings, as per Approved Document Part L of the Building Regulations.

All new dwellings must include SAP calculations to comply with these regulations. The SAP assessment showcases the project’s thermal performance and energy efficiency.

Previously, default Psi-Value figures from Accredited Construction Details (ACDs) could be used. However, with the removal of ACDs, independent assessments are now common to provide accurate Psi values for SAP Assessments. Without these independent figures, higher default values are often applied, making it harder to pass the SAP Assessment and encouraging independent junction calculations.

Independent calculations allow for adjustments to improve thermal performance as needed.