When you’re buying your first home or moving up the property ladder, the Energy Performance Certificate (EPC) might feel like just another piece of paperwork. However, the EPC rating - shown as a letter from A to G - gives a clear indication of how energy efficient a property is.
That simple letter grade could make a difference of hundreds, or even thousands, of pounds a year to your energy bills.
Every home for sale or rent in the UK must have an Energy Performance Certificate. Think of it as a report card for your property’s energy use.
The rating runs from A (excellent) to G (poor) and reflects how much energy the home typically uses for heating, hot water and lighting.
The EPC isn’t based on your actual energy bills. Instead, it looks at the building itself. An accredited energy assessor visits the property and checks things like insulation, windows, heating systems and hot water storage.
After the assessment, you receive an EPC certificate with a breakdown of the property’s energy performance, including basic details such as the address, property type and floor area. Many homes keep a copy in the meter cupboard.
The certificate also includes a list of recommended improvements, showing what changes could increase the rating and how much you might save each year.
An EPC is valid for ten years and is required for all homes sold or rented, including new builds.
The difference between ratings can be significant. Data from Carpenter Surveyors suggests that a three-bedroom semi-detached house with an A rating typically costs around £438 a year to heat and power. The same property with a D rating costs roughly £2,536 annually.
That’s a difference of more than £2,000 a year.
Even moving up one band can make a noticeable impact. Improving a property’s rating by a single band can save around £500 to £700 annually. For example, moving a three-bedroom semi-detached home from a D to a C rating could reduce annual bills from around £2,536 to £1,831.
The average UK home currently sits at a D rating. Most existing properties fall into bands C or D, while new builds often achieve B or even A ratings. If you’re viewing a home rated E, F or G, it’s worth budgeting for higher bills unless improvements are planned.
Several factors influence where a property sits on the A–G scale:
Insulation
Insulation has the biggest impact. Loft insulation, cavity wall insulation and floor insulation all help keep heat inside. Without adequate insulation, much of the heat you pay for simply escapes.
Heating systems
Modern condensing boilers are far more efficient than older models. Heat pumps score even better, although they’re still less common. The type of fuel matters too, as the EPC system currently treats electricity as more expensive than gas.
Windows
Double glazing improves efficiency, while triple glazing improves it further. Single-glazed windows, common in older properties, allow heat to escape quickly.
Hot water systems
An insulated hot water tank or a modern combi boiler will improve your rating compared to an old, uninsulated cylinder.
Age and construction
Newer homes built to current standards generally score higher. Older properties, particularly those built before 1950, often need upgrades to reach band C or above.
For buy-to-let properties, current regulations require a minimum EPC rating of E. Homes below this level cannot be legally rented unless an exemption applies.
The government previously planned to raise this requirement to band C by 2025 for new tenancies and 2028 for existing tenancies, but these proposals were scrapped in 2023. A consultation on reintroducing higher standards closed in May 2025, with outcomes still pending.
Even if you’re buying a home to live in, future changes matter. A poor EPC rating could limit your options if you decide to rent the property out later or affect its long-term value.
Not all improvements are expensive. Some low-cost changes can have an immediate impact:
Larger improvements cost more but bring bigger savings:
For the highest EPC ratings, renewable energy options such as solar panels or heat pumps can make a significant difference. After major upgrades, it’s worth obtaining a new EPC so the improved rating is reflected accurately.
The energy price cap, set by Ofgem every three months, limits the maximum price suppliers can charge per unit of gas and electricity.
For October to December 2025, the cap is £1,755 per year for a typical household paying by direct debit. However, this figure assumes average energy use. Your actual bill depends on how much energy your home consumes, which links directly back to its EPC rating.
The cap doesn’t guarantee your bill will be £1,755. Poor insulation and inefficient heating mean higher usage and higher costs, even under the cap.
Improving an EPC rating can also support property value. Buyers increasingly consider running costs when choosing a home. Two similar properties priced the same won’t feel equal if one costs £2,000 more a year to heat.
Always ask to see the EPC before making an offer. It should be no more than ten years old and available from the estate agent.
Check both the current rating and the potential rating. The potential rating shows what the property could achieve with recommended improvements. If there’s a large gap, factor the cost of those upgrades into your budget or offer price.
Look closely at the recommendations section. Some upgrades may be essential, while others may not suit your plans. Also check when the EPC was created. If improvements have been made since, the actual efficiency may be better than shown.
This article is for general information only and does not constitute financial or mortgage advice. Energy costs and regulations can change. Always check current guidance and speak to a qualified mortgage adviser about your individual circumstances.
