Super-efficient home is ready for anything winter can throw at it
Geoff and Kate Tunstall have spent six months in their new super-efficient Passivhaus, but does it live up to expectations? Sharon Dale reports.
WITH just a single radiator to heat the whole of their threebedroom detached house, you might expect Geoff and Kate Tunstall to be worried sick about winter.
But the couple can’t wait, and far from frantically stocking-up on thermal vests and woolly hats, they’re eagerly anticipating icy blasts and freezing temperatures.
“Bring it on,” says Geoff, who is keen to see how their pioneering eco home will cope with the cold.
The Tunstalls moved into the super-insulated property in Denby Dale, near Huddersfield, six months ago and the signs are they will be as snug as two bugs when it snows. They’ll also be free from the burden of gigantic gas and electric bills.
The lack of radiators, no fire, and water that is mostly heated by solar panels means their gas bill for the last quarter was £46 and more than half of that was a £27 standing charge.
The gas useage for August cost just 53 pence and for September £1.32, which accounted for cooking and back-up when the sun hadn’t sufficiently heated the water.
The electricity bill for the last quarter was £61, but photovoltaic panels generating energy mean the Tunstalls are eligible to claim the Government’s feed-in tariff of £700 a year, which represents a profit.
While the renewable technologies help, the success of this house is mostly down to the design and construction.
It is the first Anglicised version of the German Passivhaus, combining British materials and construction techniques with German technology.
It works on a simple “tea cosy” effect and relies on clever design, orientation towards the sun, careful construction and insulation three-and-a halftimes greater than required by Government building regulations.
No draughts can get in and no heat can leak out of the building, but the air is never stale, thanks to a mechanical heat recovery ventilation system that brings in fresh air from outside, warming it using 99 per cent of the heat from the outgoing air.
The Green Building Company in Huddersfield suggested the design and built the house with the help of a German computer software package to ensure almost complete air tightness and energy efficiency.
Project manager Bill Butcher says: “You can buy a prepackaged Passivhaus from Germany, but the materials are completely different.
“They use solid wall panels and stick polystyrene insulation on the outside of the house.
“They don’t fit into the local streetscape here, builders here aren’t familiar with them and planning can be an issue.
“This Passivhaus is the first to be built using British construction methods with blockwork, a cavity wall and stone cladding.
“We use the Passivhaus methodology but we have built in the English vernacular, which is a first. You can vary the design as long as you adhere to the principles.”
He adds: “What’s important is detailing beforehand and quality control on site. Everything has to be monitored from beginning to end to make sure there are no gaps, no leakage or draughts.”
The three-bedroom property, built in the garden of the Tunstalls’ Victorian cottage, cost about £141,000 to build.
A Passivhaus costs about 20 per cent more to construct than an average new-build because of the attention to detail, but promises a 90 per cent reduction in fuel bills.
Warmth generated from the sun through windows, body heat and cooking is usually all that is needed.
The idea is to maximise heat gain and minimise heat loss, so the Yorkshire house is highly insulated and has triple-glazing with large windows on its south facing front and small ones at the cold, north-facing rear of the property.
Any gaps are minimised during construction and insulation has to be continuous. Any areas liable to settlement cracks are sealed with special air tightness tape to prevent cold air seeping in.
There are no plug sockets on the outside walls and no lights in the ceiling, so the envelope and insulation barrier isn’t punctured.
Both Mr and Mrs Tunstall and the Green Building Company are hoping that the Yorkshire Passivhaus will provide a blueprint for the future of green housebuilding in Britain.
“I think the Government is starting to take note and I think British developers are starting to wake up to it, too. I’ve had lots of small builders asking me about it,” says Geoff.
The Green Building Company has just launched “Future Passiv”, a short 10-minute documentary which makes the case for Passivhaus as a standard for all UK new builds – and even for the refurbishment of existing buildings.
Presented by broadcaster Penney Poyzer, Future Passiv features the Denby Dale project
She says: “Passivhaus is a proven technique which shows that it is entirely practical and feasible to aim for buildings that use 90 per cent less energy than our current standard for buildings. If the UK is to achieve massive reductions in carbon then it is essential that we tackle the built environment. Across Europe, buildings account for 60 per cent of carbon emissions. I believe that Passivhaus can slash those emissions now.”
There is also a 60-minute technical film for building professionals, covering all stages of construction.
But most persuasive of all are the enthusiastic guinea pigs, Geoff and Kate.
“We’re waiting to see what winter brings, but so far this house has surpassed all our expectations,” says Geoff.
“It’s not just energy-efficient, it’s a lovely, comfortable house to live in.”
The Future Passiv documentary and Denby Dale Passivhaus technical film are freely available to view at Green Building Store’s website www.greenbuildingstore.co.uk
SNUG FIT: Geoff and Kate Tunstall at the Passivhaus in Denby Dale.
ENERGY-SAVING: The Passivhaus is the first of its kind to be built using British construction methods from its original German design. Its insulation and solar panels slash energy bills.