The Ecology Building Society has lifted the entry criteria for its range of green mortgages for self and custom-build homes to “accelerate the construction of energy-efficient homes to help meet the UK’s net-zero ambitions”.

The lender increases the minimum energy rating level, or Standard Assessment Procedure rating, to 88, from 85, for self-build applicants to hit when their home is completed.

It says the move supports “construction of the most energy-efficient buildings, which is critical if we are to meet our Paris commitments and tackle the climate and ecological crisis”.

The lender’s self-build mortgage starts at an initial rate of 4.15% while construction is underway. On completion, borrowers are eligible for a discount of up to 1.25% based on the Energy Performance Certificate.

It says, if the finished home is A-rated, an EPC a discount of 0.75% applies, giving a variable rate of 3.40% for the remaining term of the mortgage.

This mortgage carries a £799 application fee. Applicants can borrow up to 80% of the property’s value on a repayment basis.

The mutual adds, for homes built to “the exacting” Passivhaus standard, a greater discount of 1.25% applies on completion, resulting in a variable rate of 2.90% per cent for the rest of the mortgage.

The government has committed the UK to cut the country’s greenhouse gas emissions to net zero by 2050.

Homes made up 22% of the UK’s greenhouse gas emissions in 2018, if electricity consumption is included, according to a Department for Business, Energy & Industrial Strategy report, called Improving home energy performance through lenders, published last November.

The Ecology Building Society mortgage manager Daniel Capstick says: “Now more than ever it’s important that lenders play an active role in a sustainable recovery, helping to build back better.

“We’ve been leading the way on green mortgages for 40 years and we hope that the changes to our lending criteria will result in our borrowers building more energy-efficient homes, which is critical in the fight against climate change.”

The lender adds it also considers mortgages for renovation projects “that standard lenders may not accept including where the property is deemed not to be habitable or fallen into disrepair”.