PSI Value Calculations

PSI Value Calculations quantify heat loss at junctions within a building’s thermal envelope, ensuring your design meets the fabric‑efficiency requirements of UK Building Regulations. By modelling thermal bridges accurately, rather than relying on default values, you can demonstrate improved performance and reduce predicted energy demand.

Minimising Thermal Bridging for Better Compliance and Performance

At Stanley Sustainability, we offer bespoke PSI-value calculations to help your development reduce thermal bridging and meet compliance with Part L of the Building Regulations. By modelling junctions with precision, we help you achieve lower heat loss, improved SAP results, and enhanced energy efficiency — without relying solely on default values.

Our service is ideal for architects, developers, and energy assessors seeking to optimise building fabric performance and unlock better compliance outcomes.

What We Deliver

🧮 Custom Junction Modelling – Detailed thermal analysis using 2D/3D software for key junctions

📉 Improved SAP Inputs – Lower PSI-values that reduce DER and improve overall energy ratings

📄 Compliance Documentation – Fully referenced reports for Building Control and SAP assessors

🏗️ Design Integration Support – Advice on junction detailing to minimise thermal bridging in practice

Why It Matters

Default PSI-values can limit your ability to meet Part L targets — especially in high-performance or low-carbon designs. Bespoke calculations allow you to:

✅ Improve SAP scores and reduce carbon emissions

✅ Avoid costly upgrades to insulation or renewables

✅ Demonstrate robust thermal performance to regulators

✅ Enhance building comfort and reduce heat loss

Why Stanley Sustainability?

We combine technical rigour with practical insight. Our bespoke PSI-value service helps you:

🔧 Fine-tune junctions for maximum efficiency

💰 Lower build costs by avoiding over-specification

📊 Strengthen your compliance strategy with accurate, project-specific data

Let’s bridge the gap between design and performance — with precision.