Energy Performance Certificates: What Do They Check?
By law, most commercial buildings in the UK are required to have a valid energy performance certificate (EPC) when they are sold or let. The certificate outlines the building’s expected energy performance based on its structure and installed systems.
At Business Utility Hub, we speak to organisations every day that are trying to make sense of EPC ratings, and how they relate to their gas and electricity costs. This guide explains what EPC assessments are designed to measure, what assessors look at and how EPC information links to wider business energy decisions.
What an energy performance certificate assessment measures
An EPC assessment is carried out by an accredited assessor, and measures a property’s energy performance, rather than how a particular business uses the space. These assessments are carried out by an accredited non-domestic energy assessor. The assessor’s role is limited to inspecting the property, collecting technical information, applying the approved methodology and producing the EPC report.
EPCs focus on the fixed characteristics of a building, not behaviour, occupancy levels or working patterns. This includes the structure, installed systems and permanent features that influence how much energy the property is expected to need under typical conditions.
Because the same assumptions are applied across all properties, EPCs provide a baseline view of expected energy usage under standard conditions, using fixed assumptions about heating, lighting and occupancy.
Who commissions an EPC?
An EPC is a legal requirement when a commercial property is sold or let. In these situations, responsibility for commissioning the EPC sits with the property owner or landlord, and the certificate must be available before the property is marketed.
Where occupiers have carried out material upgrades and have the appropriate rights and consent, they may also commission a new EPC to reflect the improved condition of the premises. While this does not transfer legal responsibility for compliance, it allows the updated performance of the building to be recorded.
EPC information is then used by occupiers to assess running costs, plan improvements and review energy arrangements.
The building elements an EPC assessor checks
During an EPC assessment, the assessor reviews a range of fixed elements that affect how the building uses energy.
Building fabric and cavity wall insulation
Assessors look at how well the building retains heat. This includes:
- Wall construction and cavity wall insulation.
- Roof and loft insulation.
- Glazing type, such as double glazing.
- Evidence of existing insulation upgrades.
Buildings that lose heat more quickly typically require more energy to maintain internal temperatures.
Heating systems and controls
The heating system plays a central role in a property’s energy performance. Assessors review:
- The type and age of the boiler or heating system.
- Whether it is a more efficient boiler or an older model.
- Heating controls, including zoning and timers.
- How heat is distributed throughout the building.
Older or poorly controlled heating systems often have a noticeable impact on energy consumption.
Lighting and fixed electrical systems
Lighting is assessed based on:
- The type of lighting installed.
- Whether energy-efficient lighting or energy-saving light bulbs are used.
- How lighting is controlled.
Lighting efficiency can affect electricity usage and overall energy performance, particularly in larger commercial spaces.
Ventilation and cooling systems
Where installed, assessors review:
- Ventilation systems.
- Air handling units.
- Cooling systems used to manage internal temperatures.
These systems often account for a substantial share of overall energy use, particularly in larger or more intensively serviced premises.
Renewable energy technologies
If the property includes renewable energy technologies, such as solar panels or other renewable energy sources, these are taken into account during the assessment. Renewable energy solutions can improve a property’s energy performance by reducing reliance on grid energy.
How energy usage and performance are calculated
EPC assessments use standard assumptions to estimate how much energy the property is expected to use. This includes typical patterns for heating, lighting and hot water, applied consistently across all properties.
Because of this approach:
- EPCs do not reflect actual energy bills.
- They do not account for business-specific behaviour.
- They are not a measure of how efficiently a business manages energy day-to-day.
Instead, EPCs provide a comparative view of a building’s energy performance, helping businesses understand how their premises are likely to behave relative to other sites.
How the EPC rating and final score are produced
The information gathered during the EPC assessment is processed through approved software to produce:
- An EPC rating, shown on an A to G scale, where A represents the highest level of energy efficiency and G the lowest.
- An energy efficiency rating score.
- A potential rating if recommended improvements are made.
The final EPC rating reflects the building’s current condition. The EPC report also outlines energy efficiency improvements that could raise the rating, although there is no obligation to carry these out immediately.
How EPCs influence energy pricing and contract decisions
A valid EPC lasts for 10 years, unless significant changes are made to the building that would materially affect its energy performance. Where energy efficiency improvements have been made, renewing an EPC can reframe how a building’s future energy demand is viewed. Changes to fixed elements such as heating systems, lighting or insulation alter the baseline assumptions used to estimate how much energy the site is likely to require under standard conditions.
When suppliers price business gas and electricity contracts, they base rates on expected usage over the life of the agreement. If a renewal relies on historic consumption that no longer reflects the condition of the building, pricing can still be set as though higher demand is likely.
Reassessing an EPC after material upgrades, and looking at it alongside more recent usage data, can bring pricing closer to how the building now performs. This has the potential to impact costs when contract terms are being discussed, or where improvements are expected to reduce energy use over the long term rather than through short-term changes.
How Business Utility Hub can help
EPC information often sits behind decisions about energy costs, contract timing and long-term planning. At Business Utility Hub, we use that information to help businesses secure more competitive gas and electricity contracts. By factoring building performance into energy comparisons, we can check whether existing or proposed deals reflect how a premises operates today, rather than how it performed in the past.
Where EPC ratings or recent upgrades suggest a building should be using less energy, that can influence how contracts are approached at renewal. Our role is to spot those opportunities quickly, compare available options across the market and help businesses move onto a deal that better fits their current position.
If you are approaching your renewal, or already out of contract, the best and quickest way to see the kinds of business energy savings you could access for your business is to call us on 0800 781 2700. We will assess your current contract and find the best deal for your business in a matter of minutes.
Compare and switch your business energy today
To review your current energy costs, call 0800 781 2700 or email savings@businessutilityhub.co.uk.
Our team can provide a no-obligation review of your electricity and gas contracts.
