76% of UK investors expect sustainability to shape decisions: why accurate DSM EPCs now matter for property value

Under the Minimum Energy Efficiency Standards, commercial landlords already need at least an E rating to let, and Government has proposed tightening that over time towards B by 2030. A weak rating can limit letting options, prompt capital expenditure and feature in valuation and due diligence discussions.

Investors increasingly treat the EPC as a proxy for risk: future compliance cost, obsolescence and how easy the building will be to let or sell. A rating that understates a building's true performance can therefore cost the owner money, even if the building itself is well designed and efficient.

Many commercial EPCs are produced with simplified modelling (SBEM). That is appropriate for many buildings, but it relies on standardised assumptions. Complex or high-performing buildings, such as those with atriums, glazed cores, natural ventilation, mixed-mode systems or advanced controls, are often represented poorly by simplified methods.

Dynamic simulation modelling (DSM) using approved software such as DesignBuilder models the building hour by hour, including solar gain, thermal mass, daylight and real system behaviour. Where a building's design genuinely performs better than generic assumptions suggest, accurate DSM can produce a materially better and more defensible rating. Our guides on DesignBuilder Level 5 EPCs and modelling atriums and glazed cores explain how.

The edie report's emphasis on governance applies directly here. A better rating only has value if it stands up to scrutiny from investors, lenders, auditors and future assessors. Good-quality DSM means the model reflects the real building: measured air permeability test results, accurate fabric data, correct zoning, verified plant efficiencies and documented controls.

Shortcuts or optimistic inputs are a liability. A rating that cannot be evidenced can be challenged in due diligence or audit and undermines the trust investors are looking for. The aim is an accurate rating, not an inflated one.

Every building is different, so outcomes cannot be guaranteed, but a credible, improved EPC rating can help an asset in several ways: reducing MEES risk and the need for premature capital works; supporting lettings to occupiers with their own net zero targets; giving buyers and lenders clearer evidence in due diligence; and providing a reliable baseline for planning improvements such as solar PV or heat pumps.

Accurate DSM also helps owners test improvement options before spending money, showing which measures would genuinely move the rating and which would not.

Review the EPCs across your portfolio, particularly for complex or recently refurbished buildings, and check how they were modelled. Where a building's design or systems are unlikely to be well represented by simplified methods, consider whether a Level 5 DSM assessment is appropriate. Gather evidence early: drawings, specifications, commissioning records and air test certificates.

We provide commercial EPCs, including Level 5 DSM assessments. Contact us to discuss whether your building's current rating reflects its real performance. This article summarises the edie report as published; the research figures are those reported by edie.