Frequently Asked Questions
Not sure what an EPC is or why
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Please find below some of our most commonly asked questions. If there is a question not covered, please fill in our Contact NRG Form and we'll get back to you as soon as we can.
What is an Energy Performance Certificate (EPC)?
An Energy Performance Certificate (EPC) gives a home or non-domestic building an A to G rating and includes recommendations. It assesses the building and its fixed services using standard assumptions.
Domestic EPC ratings focus on modelled energy costs; commercial EPC ratings use modelled carbon emissions. Neither is a record of your actual bills, and a better rating does not guarantee a particular saving.
How long is an EPC valid for?
An EPC is normally valid for up to ten years. Check the latest certificate on the EPC register and confirm it covers the correct property or unit.
When is an EPC needed?
An EPC is generally required when a building is constructed, sold or let, subject to exemptions and the rules that apply to the building and transaction. Arrange it early when marketing a property.
Is a commercial property exempt from having an EPC?
Some buildings may be exempt, depending on their use and circumstances. Examples include:
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Places of Worship
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Temporary buildings with a planned use of two years or less.
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Stand-alone non-domestic buildings with a total useful floor area of less than 50 m². A small unit attached to another building is not covered by this exemption.
Are EPC assessors qualified and how do I check?
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EPCs must be produced by an accredited energy assessor. Use the government assessor search to check accreditation details: Get a New Energy Certificate
How do I find my EPC on the EPC register?
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You will be emailed with an attached PDF document which is also found on the EPC register at Find an Energy Certificate
I have had my report; why does it say, 'Insulation Assumed'?
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The assessor will gather the required data which will include evidence to support his /her conclusions If the stakeholder has any other supporting evidence, we ask this be made readily available prior to the site visit or while in the property. As this is a nonintrusive survey the assessor is limited to observations.
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If no evidence is available, the assessor may have to default the insulation based on age of the property and building regulations at the time of construction.
How do I search for an EPC certificate?
Use the government Find an energy certificate service linked above. Search by postcode, street and town, or certificate number. Check the address, certificate date and expiry before ordering another assessment. NRG is an independent assessor, not the government EPC register.
What does the EPC say about the property?
EPC’s gives simulated information about the energy performance of a property; this will include recommendation as to how to improve the energy efficiency of all properties surveyed.
How long does it take to perform an EPC assessment?
Domestic EPC’s take from 30 minutes to one hours depending on size. Commercial EPC’s can take from 1 hour to 2 days depending on the size. The assessor will not cause any inconvenience and the site survey is nonintrusive.
What is an energy assessor looking for?
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Construction of the building fabric, walls, roof floors and any relevant insulation.
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Glazing type and percentage.
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Number of open fireplaces.
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Recording the make, model and evidenced efficiency of the heating equipment using the applicable assessment methodology.
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Looking for renewable or low carbon technology e.g. solar panels, air source heat pumps.
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Total amount of low energy light bulbs.
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Ascertaining the type of heating system in situ Elec, Gas Boiler to radiators, air source heat pump etc.
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Domestic Hot water type, e.g. from Combination (combi) Boiler, cylinder and insulation measures etc.
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Calculating the exposed heat loss walls.
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Checking for excessive window area, larger than typical.
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Conservatory’s types, if its heated and or separated.
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Extensions, age and building control sign off.
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Total amount of habitable rooms.
How long till I receive the report?
Residential Reports are usually emailed within 24 hours after the site survey, but only when payment is received. Larger Commercial buildings will take longer to send.
What are the current Minimum Energy Efficiency Standards (MEES)?
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Current requirements: qualifying privately rented properties in England and Wales must meet EPC E unless a valid exemption is registered. This covers new and continuing tenancies, with continuing tenancy requirements applying to domestic properties since 1 April 2020 and non-domestic properties since 1 April 2023. An F or G rating does not itself prohibit a sale.
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Commercial plans: the government intends to introduce EPC B from 2031 for privately rented non-domestic buildings over 1,000 m², where cost effective. Buildings below 1,000 m² are intended to remain subject to EPC E. The previously proposed EPC C milestone for 2027 will not proceed. These changes require legislation; details of the floor area threshold remain to be confirmed.
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Residential plans: the government has announced an EPC C equivalent standard from 1 October 2030 for qualifying privately rented homes, using reformed EPC measures, with a planned £10,000 cost cap. These changes require legislation and do not replace the current EPC E requirement or the current £3,500 including VAT improvement cost cap. Exemptions have specific conditions and evidence requirements.
MEES advice reviewed 18 October 2026. Check the official guidance below for the rules and exemptions that apply to your property, or contact NRG to discuss your EPC and suitable improvements.
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