Watt a Save - Energy efficient new homes

The energy efficiency of new build homes





The home building industry is adapting at pace to support the country’s net zero targets and deliver increasing energy and thermal efficient homes.

In 2022, The Home Builders Federation released its first 'Watt a Save' report comparing the energy performance of new build homes with older properties. HBF continues to examine the potential cost savings and energy efficiency of new build homes in line with quarterly government EPC data and changes to national energy costs.



The latest energy efficiency figures

Last updated: November 2024

Calculations are based on the Ofgem price cap from October 2024, using data from EPC registrations of new and existing properties in the year to 30 September 2024.

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New build homes emit 65% less carbon a year

The average new build home emits 1.22 tonnes of carbon per year, just 35% of that of the average older property, which emits an average of 3.51 tonnes per year.

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86% of new builds have an A or B EPC rating

New build homes are increasingly more energy efficient. Less than 5% of existing older properties achieve an A or B Energy Performance Certificate rating (EPC).

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Making energy bills up to 65% cheaper

The average new build energy bill could be more than £130 a month cheaper, based on all property types. The savings rise to £165 a month when comparing houses specifically - totalling over £1,980 a year.


Energy usage per property type

Average reduction in energy usage

When comparing all property types, new build properties use an average of 60% less energy than older counterparts, cutting the average energy bill by more than £130 a month. The average new build house uses 65% less energy than older houses.

Calculations are based on Government's EPC registrations data of new and existing properties in the year to September 2024 and Ofgem's October 2024 energy price cap.


Average energy use per m2

Critics of new build homes often suggest new properties are more energy efficient as they are smaller. EPC data evidences that this isn't the case: new builds are not only bigger on average, but also use less energy per m2.

According Live tables on Energy Performance of Buildings Certificates for September 2024, the average new build home = 88.5 m2 compared with the average existing = 86m2


Average carbon savings

On average, new build properties emit 65% less carbon than older counterparts, cutting annual emissions by 2.29 tonnes per property.

The average new build house emits 67% less carbon than older houses. Buyers of new build properties in 2023 reduced carbon emissions by 500,000 tonnes.


Energy bill savings by property type

Average energy bill savings

On average, new build homeowners could save more than £130 a month on their energy bills, amounting to £1,574 a year, compared with purchasers of older properties. This saving rises to £165 per month when comparing the energy performance of houses specifically, rather than flats or bungalows, totalling over £1,980 a year.

Prices are based on Ofgem’s price cap for October 2024, using Government's EPC registrations data of new and existing properties in the year to 30 September 2024.


EPC ratings data

EPCs of new build and existing homes in the year to September 2024

86% of new build homes achieved the highest levels of energy performance (A or B EPC) compared with less than 5% of older homes.

Calculations are based on Government's EPC registrations data of new and existing properties in the year to 30 September 2024.

Watt a Save reports

HBF issued Watt a Save reports from October 2022 to July 2023.

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