The Future Homes Standard Is Now:
The Present
Welcome to DSMHEM LTD. Please click below to see our full range of services -
U-Value & Kappa Value Calculations
We provide accurate thermal transmittance (U-value) calculations for floors, walls and roofs in accordance with BS EN ISO 6946 and BS EN ISO 13370.
These feed directly into your SAP, SBEM, and Part L assessments and help you optimise your building’s insulation specification
Energy Statements
Local planning policies often set sustainability targets above Building Regulations requirements. These must be addressed through an Energy Statement.
The National Planning Policy Framework (NPPF) requires local authorities to promote sustainable development, whilst still allowing them to impose additional targets.
PSI Ψ Value Calculations
We calculate accurate linear thermal transmittance (Ψ-values) for junctions and thermal bridges in accordance with BS EN ISO 10211. Using bespoke PSI values instead of defaults improves your SAP and SBEM results, reduces heat loss, and can reveal valuable specification savings.
SBEM Commercial EPC
SBEM, or the Simplified Building Energy Model, is the standard methodology for evaluating the energy performance of non-domestic buildings across the UK. The calculation covers heating, cooling, ventilation, and lighting demands, providing a comprehensive picture of the building’s annual energy consumption and CO₂ emissions
SAP 10.3
Energy Performance Certificates
SAP 10.3 is the latest interim calculation methodology, set to be released alongside the Future Homes Standard in 2026. It acts as a stepping stone to the full Home Energy Model (HEM), featuring updated carbon factors, a new notional dwelling specification and an improved BREL report to help demonstrate Part L compliance.
Part O - Simplified Assessment
The Simplified Method offers a straightforward, prescriptive route to
Part O compliance. It limits solar gain through glazing and ensures good cross-ventilation, controlling factors like glazing area ratio, openable window area and orientation — rather than modelling temperatures directly — to keep overheating risk acceptably low
Overglazed Extension Asessments
Planning a heavily glazed extension? Where glazing exceeds 25% of the floor area, a compliance calculation is mandatory. We carry out the necessary assessments — whether an Area Weighted U-Value or a full SAP calculation — and supply a report suitable for Building Control submission.
Home Energy Model (HEM)
Energy Performance Certificates
Unlike SAP 10.3,(HEM) requires significantly more detailed data and uses a new centralised platform called ECaaS. The assessment workflow changes dramatically — from a fast 20-minute desktop task to an in-depth technical process taking over an hour. HEM is scheduled to replace SAP 10.3 by June 2028
TM59 Dynamic Thermal Modelling
Dynamic Thermal Modelling utilises validated building simulation software to calculate internal temperatures on an hour-by-hour basis for each dwelling over a typical summer period. The assessment is carried out in accordance with CIBSE Technical Memorandum 59 (TM59). Pass criteria are: bedrooms must remain below 26°C for more than 1% of occupied hours, and living rooms must remain below 28°C.
Water Consumption Calculatuons
Design calculations carried out in accordance to Approved Document G 2015 of the Building Regulations.
As Built calculations carried out using manufacturer or WRAS and or UWLA data and grey or rain water technologies.
Unprecedented Velocity.
Impeccable Reliability.
We pride ourselves on both accuracy and punctuality, working with you and for you,
not against.
Most compliance consultants simply deliver the certificate and move on. At DSMHEM, we do more.
We can handle every required design calculation, and compliance document through one dedicated contact and a single coordinated team.
From planning to handover, everything is managed smoothly whilst we actively find cost-saving opportunities that don’t compromise your EPC rating or regulatory sign-off.
We Take Pride in Our Numbers
15+
Hundreds
Thousands
Years of Experience
Of Happy Customers
Of Surveys Completed
Trusted By:
Are You Ready to Accelerate Your Projects?
Architects design to a brief, balancing aesthetics, function, programme, and cost while whilst navigating the many constraints of building regulations. They generally use standardised material specifications that achieve compliance without re-examining every detail.
Most assessors and firms simply certify compliance to a threshold. Their job is to tell you whether you’ve passed. They are paid a fixed fee to produce a certificate — not to explore whether a better insulation spec, optimised thermal bridging, or revised air permeability target could maintain your EPC rating at a lower build cost.
Consequently, almost every development we review contains hidden opportunities in U-values, thermal bridging, air tightness, and system choices. Moving away from the default notional dwelling approach frequently reveals unnecessary costs that deliver little or no extra performance.