The Independent has given a publicity boost to the Passivhaus approach to energy efficiency with a showcase of a converted railway cottage in Hertfordshire.
Homeowners Andy and Lorna Simmonds decided to make their Herefordshire home more energy-efficient after their twins were born.
The couple negotiated a residential mortgage with the Ecology Building Society – making use of the ethical mutual’s C-Change sustainable homes mortgage discount scheme – and added a south-facing extension.
It includes large windows to capture solar energy and a new, super-insulated, hot water cylinder. They also insulated the existing solid-wall house with external insulation and added triple-glazed windows and doors, as well as a ventilation system with heat recovery and a very small, efficient natural-gas boiler.
The extension also includes a “green roof”, planted with a wildflower and meadow mix, while Mr Simmonds has moved his home office to a salvaged railway carriage in the garden.
The Passivhaus principle is not suitable for all homes. While it can be easily adopted into new-builds, not all existing properties can be adapted adequately to achieve full Passivhaus certification. If it isn’t feasible, homes can be certified to an EnrPHit standard, which are less rigid.
The Ecology Building Society has promoted Passivhaus by offering a mortgage discount scheme for the last five years. Homes which receive the Passivhaus or EnerPHit standards qualify for a discount of 1.25 per cent off the mutual’s standard variable mortgage rate. The discount currently reduces the cost to 3.9 per cent APR.