Thermal Performance Calculations for Building Fabric and Junctions
From walls, floors, roofs and glazing to thermal bridges and junction details, we help project teams demonstrate fabric performance clearly for SAP, SBEM, Part L and Building Control requirements.
Measuring Heat Loss Through Building Elements
A U-Value measures how easily heat passes through a building element, such as a wall, floor, roof, window or door. The lower the U-Value, the better that element is at reducing heat loss.
Accurate U-Values are essential for energy compliance because they influence SAP, SBEM, EPC ratings and overall building performance. They also help Building Control understand whether the proposed fabric specification meets the required thermal standard.
Understanding Heat Loss at Junctions and Thermal Bridges
Psi-Values measure heat loss through junctions where building elements meet, such as wall-to-floor, wall-to-roof, lintels, corners, sills and jambs.
These areas are known as thermal bridges because heat can escape more easily through them than through the surrounding insulated fabric. Calculating Psi-Values helps provide a more accurate picture of the building’s real thermal performance.
U-Values are a key part of demonstrating how well the building fabric performs.
U-Value & Psi-Value Calculation Pricing
| Calculation Type | Price (No VAT) |
|---|---|
| U-Value Calculations per calculation | Circa £50 |
| Psi-Value Calculations per junction | Circa £100 |
Accurate Fabric Performance Supports Better Compliance
U-Values and Psi-Values can have a significant impact on whether a project passes SAP, SBEM or Part L compliance checks. If values are guessed, missing or too optimistic, the final assessment may not reflect the actual building specification.
We use the information provided in drawings, specifications and product data to prepare clear calculations that can support compliance submissions and reduce uncertainty.
SAP and SBEM Support
Thermal values are used within residential and commercial energy assessments.
Building Control Evidence
Clear calculations can support review, approval and project records.
Better Specification Decisions
Understand how insulation, build-ups and products affect fabric performance.
Reduced Guesswork
Replace assumptions with calculated values based on actual construction details.
Clear Thermal Calculation Support for Your Project
- Review of drawings, specifications and construction build-ups.
- U-Value calculations for walls, floors, roofs, glazing and doors.
- Psi-Value calculations for junctions and thermal bridges where required.
- Use of manufacturer data, certificates or product information where available.
- Advice on missing information or unsuitable assumptions.
- Support for SAP, SBEM, EPC and Part L compliance.
