Ecology Building Society has boosted discounts on green mortgages for self- and custom-build homes by up to 1.50%.

The mutual’s self-build mortgage starts with an initial rate of 4.65% (which lifts to 4.99% from 1 August). On completion of the works, borrowers are eligible for its C-Change Sustainable Homes product discounts that range from 0.50% to 1.50% based on the standard assessment procedure rating in the energy performance certificate, or if the property is accredited to the Association of Environmental Conscious Building standard, or the Passivhaus low energy standard.

Previously, discounts had ranged from 0.50% to 1.25%.

It adds that the move also includes the addition of dedicated discounts for homes built to a SAP rating from 100 to 109 and SAP ratings of more than 110, of 1.00% and 1.25%, respectively, which the building society calls A+ and A++.

It says this rating “reflects the environmental performance of homes built to a standard that generates more energy than they consume”.

The lender points out that building regulations require that a SAP calculation and a predicted ‘on construction’ energy performance certificate be submitted for new dwellings prior to the start of building work.

It adds it will consider loans on a wide range of construction techniques including those using non-standard materials and modern methods of construction. `

The mutual also offers a renovation mortgage, where a property is being purchased for renovation or retrofit. It will consider lending on homes in any condition, “as long as the works required improve the energy efficiency of the property”. Its retrofit discounts apply once the renovation is complete.

The firm says: “The decision to enhance the discounts comes at a time when the government is recognising the urgent need to reduce the carbon impact of house building and has stated that new homes much reduce carbon emissions by 75% by 2025.”

Ecology Building Society mortgage manager Daniel Capstick adds: “Now more than ever it’s important that lenders play an active role in incentivising green building and helping to reduce energy bills.

“We’ve been leading the way on sustainable mortgages for over 40 years, and we hope that the updates to the C-Change discounts will encourage our borrowers to build even more energy-efficient homes, which is critical in the fight against climate change.”