Last updated: 14 Aug 2026
The energy efficiency of new build homes
New build homes are designed to use less energy, cost less to run and produce lower carbon emissions than older properties. Built to modern building standards, including Part L, Part S and the forthcoming Future Homes Standard, they offer better insulation, cleaner heating technologies and lower running costs from day one.
HBF’s latest research - Watt a Save: The New Build Advantage - has been produced with Octopus Energy. It examines the impact of energy efficiency designed in to today’s new build homes, including energy bill savings, reduced carbon emissions, improved satisfaction and long-term value.
Key findings
- Virtually all new build homes achieve an A or B EPC rating (87%), compared with just 5% of older homes.
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On average, new build homes use 30% less energy than older homes.
- The average new build home (EPC A or B) is powered by around 30% less energy than the average older property (EPC D), and around 40% less than existing F- or G-rated homes.
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On average, new build homes cost around £420 less a year to run than older homes.
- On average, new build homes are around 20% cheaper to run than older homes, and around 30% cheaper to run than EPC F- and G-rated homes.
- The average new build home (EPC A or B) costs around £1,574 a year to power, compared with £1,995 for the average older home (EPC D), a saving of over £420.
- New build homes can cost around £620 a year less to run compared with older F- or G-rated properties, where the average running costs are £2,192.
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On average, older homes produce 50% more carbon emissions than new build homes every year.
- The average older home (EPC D) emits around 50% more carbon than the average new build (EPC A or B).
- Existing properties with an F or G EPC produce around 74% more carbon than the average new build.
- Energy-efficient and low-carbon features can add around 6% to a home's market value, while customer satisfaction with technologies such as heat pumps and solar PV remains high.
- Some new builds are 'zero bill' homes, combining solar panels, battery storage and heat pumps to deliver net-zero operational carbon and fixed £0 energy bills for a set period.
Understanding the findings
The UK's housing stock is among the oldest and least energy efficient in Europe. By contrast, today’s new build homes are designed to meet increasingly rigorous building standards making them significantly more energy efficient, cheaper to run and kinder to the environment.
Our research highlights the energy-saving features already found in new build homes and the real-world benefits they deliver to homeowners.
Reviewing the energy performance of new build homes
Based on Government's Energy Performance Certificates (EPC) registrations data of new and existing properties in the year to December 2025, 87% of new builds have an A or B EPC rating.
Just 5% of existing older properties achieve the same level of energy performance as the average new build homes. In fact, the average older property has a D EPC rating, with 41% receiving this energy performance score or less.
Calculations are based on Government's EPC registrations data of new and existing properties in the year to December 2025.
Reducing household energy use with new build homes
On average, households living in new build homes (average A or B EPC rating) use significantly less energy than those in the average older property, with a D EPC rating.
In fact, our research shows that new build homes are powered by around 30% less energy than the average older home and around 40% less than existing F- or G-rated homes.
A property with an A or B rating uses 90 kWh/m2 of gas, and 39 kWh/m2 of electricity a year, on average - a cumulative total of 129 kWh/m2. By comparison, EPC D-rated homes use 145 kWh/m2 of gas and 43 kWh/m2 of electricity a year, and EPC F- and G-rated homes use 170 kWh/m2 of gas and 47kWh/m2 of electricity a year.
This means an average 90m² new build home consumes around 11,599 kWh of gas and electricity per year, compared with 16,896 kWh for the average older home, and 19,540 kWh for F- or G-rated properties.
‘Zero bill’ new build homes now delivered by some developers are designed to generate more energy than they consume, highlighting the potential for homes to not only reduce costs but also contribute to net-zero energy goals.
The potential energy bill savings of new build homes
Our research shows that new build homes are significantly cheaper to run than older properties because they are built to higher energy efficiency standards, using modern building materials and technologies.
On average, based on a typical 90m2 home, a new build homeowner could save around £420 a year on energy bills compared with someone living in an older EPC D-rated property.
Average annual energy costs for a new build home are £1,574, compared with £1,995 for the average older home (EPC D), making new builds around 20% cheaper to run.
The savings are even greater when new build homes are compared with the least energy efficient older properties.
Energy bills for older homes with an F or G EPC rating are around £2,192 a year on average which is about 40% more than the average new build home. Therefore, choosing a new build could save homeowners around £620 a year on energy bills compared with older F- or G-rated properties.
2025 Average Energy Costs (£ per m² per year)
The average carbon savings of new build homes
On average, older properties produce around 50% more household carbon emission than new build homes. Existing properties with an F or G EPC produce around 74% more carbon than the average new build.
On average, new build homes (EPC A or B) produce approximately 2,179kg of carbon per year, compared with around 3,266kg for the average older home (EPC D) and up to 3,787kg for the least efficient, F- or G-rated properties.
This means new build homes reduce household emissions by around a third on average (33%), and produce around 43% less carbon than older F- or G-rated homes.
‘Zero bill’ new build homes designed to ensure that day-to-day energy needs are powered by clean energy generated by the home. As a result, routine energy use can be delivered with little or no operational carbon emissions.
2025 Average CO₂ Emissions
Methodology
This research calculates the energy cost and carbon emission differences between new build homes and older housing stock. It compares real-world data and standardised energy metrics to evaluate the real-world benefits of new standards and green technologies designed into today’s new build homes.
The report’s energy and carbon findings are based on a typical 90m2 property.
The broader findings are based on analysis of the Government’s EPC data for the year to December 2025, alongside actual anonymised smart meter usage data from Octopus Energy covering the period from 1 January to 31 December 2025.
Previous Watt a Save reports
Published in February 2026 in partnership with Octopus Energy, HBF's latest research has revealed that modern, energy-efficient new build homes offer significant cost savings and major reductions in household carbon emissions compared to older properties.
On average, households living in new build homes benefit from significantly lower energy costs, saving around £420 a year compared to those living in older properties. New-build homeowners spend on average around £1,574 per year on energy, while homeowners in older homes pay closer to £1995, making new build homes 21% cheaper to run.
View the reportHBF's July 2023 Watt a Save report found new build homebuyers were saving over £400 million a year in energy bills, as well as collectively reducing carbon emissions by over 500,000 tonnes.
Download reportOur February 2023 Watt a Save Report found new build properties are significantly more environmentally friendly than older equivalent properties, emitting just 1.4 tonnes of carbon a year, compared to the 3.6 tonnes that existing properties emit.
Download the reportOur first Watt a Save report found new build home buyers were saving an average of more than £2,000 on household bills per property each year, equivalent to £173 a month. For buyers of houses, as opposed to flats the savings were even greater at £220 per month.
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