2026 Energy and Mortgage Market Context

• Energy Costs: The rise in the OFGEM price cap to £1,758 and NimbleFins' higher average estimate of £1,843 highlights the increasing financial incentive for homeowners to adopt self-sufficient energy technology.

• Project Scaling: The shift from a 2025 target to 2026 operations marks a transition from a pilot phase to a more established market offering for "Zero Bills" homes.

• Mortgage Integration: The partnership with Perenna remains a key factor in 2026, as lenders increasingly use energy efficiency to offer more competitive long-term fixed rates to borrowers.

The initiative, with lender Perenna, also unlocks cheaper mortgage rates for borrowers as they will be using more sustainable energy.

The Zero Bills mortgage rewards home buyers who move into properties with green energy technology such as heat pumps and solar panels.

The average gas and electricity bill per UK household is around £1,800 a year in early 2026 according to NimbleFins research. With the OFGEM Energy Price Cap for the first quarter of 2026 set at £1,758, a typical household could be in line for a financial boost of over £17,500 to £18,430 over a 10-year period by eliminating these costs through a 'Zero Bills' home.

Perenna has integrated the Zero Bills initiative into its affordability calculations and because green energy is cheaper, the homes are more affordable and therefore can have cheaper mortgage rates.

Not only offer Zero Bills customers lower rates than its standard mortgage customers, it will also reduce the deposit needed.

Octopus says this drives down the barriers to buying greener homes.

Two thirds of adults under 30 say sustainability is an important factor when looking for a home, according to Make UK Modular.

Octopus Energy initially aimed to accredit 50,000 homes globally by the end of 2025. Having surpassed its early certification milestones through contracts with major developers and housing providers, the company continues to expand the 'Zero Bills' initiative as a standard for sustainable new-build housing in 2026.

Accredited plots span a range of tenure types, including private and shared ownership, as well as affordable and social rent, Octopus said.

Michael Cottrell, Zero Bills homes director at Octopus Energy, said: "We’ll keep innovating and partnering with like-minded companies to further speed up the move towards affordable, cleaner living.”

Perenna is a challenger on the mortgage market, offering borrowers to lock in their rates for the entire term if they want to, so their monthly payments never change. They also have no maximum age limits to help older buyers.

Rachael Hunnisett, associate director at the Green Finance Institute, said it was a "pioneering step forward for the mortgage industry".

She added: "Collaboration and innovation – ensuring that changing customer needs are at the heart of product design – is the key to transitioning the UK housing stock towards net zero.”

Read more:

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• What’s the difference between an air source heat pump and a ground source heat pump?

• How Much Electricity Does My Appliance Use? From Fans to Slow Cookers

• Average Cost of Electricity per kWh in the UK