For businesses leasing office spaces, retail units, or industrial properties, the Energy Performance Certificate (EPC) is often a key factor in deciding premises. But unlike residential properties, Non-Domestic EPCs come with a range of assumptions and limitations that can mislead tenants about actual energy costs and comfort.
In this article, we’ll break down:
How Non-Domestic EPC scores are calculated
Why commercial EPC ratings may not reflect real-world energy use
What tenants and landlords need to watch out for in 2025
The Difference Between Domestic & Non-Domestic EPCs
| Feature | Domestic EPC | Non-Domestic EPC |
|---|---|---|
| Methodology | Standard Assessment Procedure (SAP) | Simplified Building Energy Model (SBEM) |
| Focus | Fabric, heating, lighting, insulation | Occupancy patterns, lighting, HVAC systems |
| Energy Use Assumptions | Based on standardised family use | Hypothetical “typical occupancy” scenario |
➡️ Learn more about our commercial EPC assessments.
Why Non-Domestic EPC Ratings Can Mislead Tenants
1. EPCs Are Based on Hypothetical, Not Actual Usage
SBEM calculations for commercial EPCs assume a standardised pattern of occupancy and usage.
For instance:
An office space designed for 100 staff will be rated as if fully occupied daily.
A shop unit may be modelled as constantly open and lit, regardless of actual trading hours.
🔴 Impact: A business operating at reduced hours or low staff occupancy may find that the EPC overstates likely energy consumption.
2. Tenant Fit-Outs Are Ignored in EPC Calculations
EPCs are based on the ‘base build’ condition of the property.
Any tenant-specific fit-outs, such as:
High-efficiency LED lighting
Advanced HVAC systems
Additional insulation during interior remodelling
are not reflected in the EPC score unless formally updated post-occupation.
➡️ Ensure your fit-out improvements are captured in a post-occupancy EPC assessment.
3. Lighting & HVAC Defaults Penalise EPC Scores
If an assessor cannot verify:
Lighting efficiencies
HVAC performance certificates
Zone heating controls
the EPC software defaults to assumed low-efficiency values, resulting in artificially poor ratings.
🔴 Impact: Tenants may reject perfectly efficient properties based on misleading EPC scores.
4. EPCs Don’t Factor in Operational Behaviour
Energy-intensive practices (e.g., heavy machinery, server rooms) are not accounted for in EPCs. Conversely, a tenant with eco-conscious practices may operate at much lower actual energy use than the EPC suggests.
The Business Implications of Misleading Commercial EPCs
| Issue | Tenant Impact | Landlord Impact |
|---|---|---|
| Overstated Energy Costs | Tenants may avoid renting | Properties stay vacant longer |
| Undervalued Green Upgrades | Eco-conscious tenants overlook the property | Landlords miss premium rental opportunities |
| MEES Compliance Disputes | Tenants assume property is non-compliant | Landlords need to provide post-fit-out EPC reassessments |
➡️ Ensure your commercial property’s EPC reflects real efficiency with EPCrate.
How Tenants Can See Beyond the EPC Score
a) Request Full EPC Data Sheets
Beyond the headline rating, the EPC report contains detailed assumptions about lighting, HVAC, insulation, and occupancy that explain the score.
b) Ask About Recent Energy Upgrades & Fit-Outs
If the landlord has invested in efficiency improvements post-assessment, ensure this is documented and reflected in a fresh EPC.
c) Consider an Occupancy Assessment
For large commercial tenants, commissioning an Occupancy Assessment can reveal actual energy use patterns and provide more realistic efficiency expectations.
How EPCrate Helps Landlords & Tenants Navigate Non-Domestic EPC Accuracy
At EPCrate, we specialise in:
Detailed non-domestic EPC assessments that minimise default assumptions
Post-fit-out EPC updates to ensure tenant improvements are recognised
Guidance for landlords on MEES compliance and tenant communication
➡️ View EPCrate’s commercial EPC pricing
➡️ Contact us to discuss your non-domestic EPC needs
Conclusion: Don’t Let a Flawed EPC Misrepresent Your Commercial Property
Non-Domestic EPCs are useful compliance tools, but for tenants, they should be seen as indicative, not absolute, measures of operational energy use. For landlords, ensuring the EPC accurately reflects property improvements is key to attracting tenants and meeting legal obligations.
EPCrate ensures your commercial EPC is a reliable reflection of real-world efficiency.
