Santander offers up to £30,000 extra borrowing for buyers of zero-energy bill homes
Santander has become the first major UK bank to offer significantly higher mortgage lending to buyers purchasing homes that generate their own power and incur no energy bills.
Under a new partnership with Octopus Energy, the bank will lend up to £30,000 more to customers buying properties built to the energy firm's 'zero bills standard'. These homes are equipped with solar panels, heat pumps and battery storage systems that eliminate electricity and gas costs for at least five to 10 years.
The enhanced borrowing reflects updated affordability calculations that account for households having more disposable income when they pay nothing for energy. Santander says a family buying a five-bedroom home could potentially access the full £30,000 additional lending compared with standard affordability assessments.
How the scheme works
More than 6,000 homes have been approved for Octopus's zero bills programme since it launched in 2022, through partnerships with developers including Vistry, Thakeham, Wates and GS8. The scheme, which also operates in Germany, France and New Zealand, has seen rapidly growing interest, with heat pump sales up 103 per cent between February and March 2026 as geopolitical tensions pushed conventional energy prices higher.
Scotland's first zero bills development opened in January 2026 at Tranent Grove in North Dundee, with 57 properties carrying a 10-year energy bill guarantee. Octopus aims to deliver another 94,000 such homes by 2030.
The properties generate electricity through rooftop solar panels, with excess power stored in batteries for use at night. Heat pumps provide heating and hot water. There is no standing charge on the tariff, though a fair use allowance applies and electric vehicle charging must be paid for separately.
Mortgage rates and eligibility
Santander will apply the same interest rates to these mortgages as its standard products. The bank's lowest fixed rates for home movers currently start at 4.55 per cent for borrowers with deposits of at least 40 per cent. It has also introduced new 10-year fixed deals from 5.19 per cent.
The bank has not specified exactly how much extra customers can borrow relative to their income. Under loan-to-income rules updated in August 2025, Santander typically lends up to 4.45 times annual income for those earning under £45,000, up to 5 times for incomes between £45,000 and £100,000, and up to 5.5 times for those earning above £100,000.
Ben Merritt, head of mortgages at Santander UK, said the bank was helping customers make the most of lower household outgoings.
By taking into account the 10-year zero bills guarantee from Octopus, this provides greater flexibility in the amount some customers are able to borrow, helping more people access homes that are designed to be energy efficient and more affordable to run.
Wider green mortgage market
Santander joins a growing number of lenders offering green mortgage products. More than 60 UK banks and building societies now provide green mortgages, up sharply from just four in 2019, though such products still represent only around one in nine deals on the market.
Most green mortgage schemes require properties to have an Energy Performance Certificate rating of A or B to qualify for benefits such as lower interest rates or cashback, though some lenders will accept C-rated homes if owners commit to making energy improvements. More than 350,000 heat pumps have now been installed across the UK, with over half of those fitted since December 2022.
The government published its Warm Homes Plan in January 2026, earmarking £15 billion to upgrade 5 million homes by 2030 and reduce fuel poverty. From 28 April 2026, the Boiler Upgrade Scheme offers grants of £7,500 for air-to-water and ground source heat pumps, and £2,500 for air-to-air heat pumps.
Banks face regulatory targets requiring a certain proportion of their lending to go towards energy-efficient properties, creating incentives to develop green mortgage products.
New build premium concerns
Mortgage broker Aaron Strutt of Trinity Financial welcomed the additional borrowing capacity but cautioned buyers against overpaying.
The fact that buyers may be able to borrow up to £30,000 more will be helpful for some so they can purchase the property in the first place.
However, he warned that new builds typically command a premium over second-hand properties. Research consistently shows new build homes sell for 15 to 30 per cent above comparable existing properties in the same location, with this premium typically eroding within three to five years of completion. A University of Cambridge study found new build prices can drop 5 to 10 per cent in the first one to two years as properties transition to the resale market.
Parts of the new build property market are really struggling now, so an incentive like this will be welcomed by property developers and those keen to buy new build homes,Strutt added.
Buyers considering the Santander-Octopus scheme should compare the rates and borrowing amounts available with offers from other lenders to ensure they secure the best overall deal.