STEPHEN LEWIS visits a 'home of the future' which costs almost nothing to heat

ON a quiet residential street near Hob Moor stands what just could be the house of the future.

Tim and JJ Shepherd's three-bed detached home doesn't look particularly unusual.

It is obviously new, and contemporary in design. Downstairs, there's a huge open-plan living area combining sitting room, dining room and kitchen. Huge windows on three sides allow the light to pour in. There's also a small snug, for anyone who wants to be private.

Up the kinked wooden stairs that open off one side of the living space there's an airy landing, three generous bedrooms, bathrooms, a laundry room and a closet.

Outside, there's a bamboo deck on two sides of the house that looks out over a garden that has been deliberately turned into a wildflower meadow.

"I've lived in a high rise flat for 30 years!" says Tim, a retired geography teacher who, with his wife, has just returned to the UK after three decades in Singapore. "I wanted a garden!"

York Press:

Tim and JJ Shepherd on the bamboo decking outside their passivhaus

It's a lovely home to retire to. But it isn't the light, or the space, or the quality of the design that make this house so unusual.

It is the fact that, even on a dank, chilly day at the end of a cold English August, it is as warm as toast inside. Even though it doesn't have any central heating. Or, in fact, any heating at all, apart from a single electric bar.

This is a 'passivhaus'. And what that means is that it costs almost nothing to heat.

It is made of a wood frame, that is insulated with a mixture of mineral wool fibre (a bit like fibreglass) and polystyrene. The windows are triple-glazed, and in addition to the insulation, the walls are lined with an air-tight membrane. In effect, the whole building is enclosed in an air-tight envelope. There are no draughts, and no heat leaking wastefully through poorly insulated walls or ceilings.

"Every bit of heat that is generated in this house is saved, whether it's from the kettle, our body heat, the heat that comes from the washing machine or the hoover," says Tim.

But if the whole house is completely sealed and airtight like that, doesn't it get dreadfully stuffy?

Well, no. The reason for making the house airtight is so that ventilation can be properly controlled.

In the small closet opening off the landing upstairs is what is called an MVHR - a 'mechanical ventilation with heat recovery' system. This circulates air around the house, and also draws fresh, filtered air into the house. Stale, warm, damp air from inside the house is expelled - but the warmth is captured by a heat recovery unit on the way out.

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Fresh and airy: the living space in the passivhaus

The result? No heat is wasted, there are no chilly draughts, but the air inside always smells and feels fresh. JJ has only been in the house a few weeks, but she has noticed that already. Even the laundry, aired in the small laundry room, smells as fresh as if it had been aired outside, she says.

The house was designed by York architect Phil Bixby, of Constructive Individuals, and built by North Yorkshire-based Kent Building Developments, owned by Steve Kent.

Although Tim and JJ haven't lived in the house long enough to have worked out precisely how much it will cost to heat, Phil says a house of this kind would normally cost between £100-£120 a year to keep warm. Except that this one won't cost even that much.

On the roof are a series of photo-voltaic solar panels. And they generate enough electricity to run the entire house - heating, cooking, lighting, washing machine, the works. There are even two charging points for electric cars - meaning that the Shepherds charge their electric Renault Zoe car free. So not only no heating costs, but no mileage costs, either.

There are other futuristic aspects to this house. There's an electronic security system, complete with cameras, which means the Shepherds can see who exactly is calling at their house even when they're away. The electric-powered blinds and the lights, too, can be operated remotely, giving the impression someone's home even when they aren't. And the cooker is electric - so it, like everything else, runs off the solar panels and there are no gas bills.

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Architect Phil Bixby at the house while it was under construction

Tim and JJ liaised with Phil from 10,000 miles away in Singapore while the house was being built. But even so, JJ admits she was gobsmacked when she arrived at the beginning of August - a few weeks after Tim - and saw the house for herself for the first time.

Tim has a sister in York, so the couple have visited many times. But coming from Singapore, JJ is used to being warm. She'd been a little worried about the thought of moving to a cold house.

"But I can't believe I'm in England! It's so warm!" she says. At home in Singapore, she was used to wearing shorts and a T-shirt around the house, because of the heat. "And most of the time I have been wearing shorts and a T-shirt here!" she says. "If anything, it is too warm!"

Which isn't a problem. "If it does get too hot, you just open a window," Tim says.

Given that this is such a lovely house to live in, why aren't there more like it in York?

To Phil Bixby's knowledge, there are now four passivhauses in the city. He himself has had a hand in building three of them.

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Building firm boss Steve Kent studying the solar panels on the roof while the house was under construction

So why aren't more builders and architects doing the same?

One reason is cost. It does cost more to build a passivhaus, Phil admits. Not much more. "But I would say it is 5-10 per cent more expensive than conventional building."

One of the reasons for that, however, is that so few architects and developers are geared up to build a home to these standards. To be qualified as a passivhaus, a new home has to undergo a rigorous certification process, which involves an air-tightness test.

In conventionally built homes, five times the volume of air contained in the home will leak out through the walls and doors every hour. To qualify as a passivhaus, only about half of the total volume of air in the house is allowed to leak out in an hour (the actual target is 60 per cent, or 0.6 of the air volume). A passivhaus is about ten times as airtight as a conventional house, in other words. But achieving that means constant checks on joints and seals as the home is being built.

Phil believes, however, that if more architects and builders began building passivhauses, and if passivhaus standards became the norm, then the costs would come down.

And that would have huge benefits, he says.

Not only would people be living in homes they could afford to heat easily during cold winters, we would be doing our bit to help save the planet too.

Tim and JJ's home isn't burning any fossil fuels to remain warm and well-lighted - it's just using the power of the sun. So York's carbon footprint is being reduced, and Tim and JJ themselves will see the benefit in very low or non-existent fuel bills.

They could even end up making a bit of money, by selling excess power from their solar panels to the grid. The rates for that are not very generous - but however little they make, it is better than having a huge gas and electricity bill.

Phil Bixby would like to see builders of social housing taking the lead on passive housing, in the hope that one day these standards will become the norm.

"If you're building social housing, it is very important that the people who live in that housing can afford to heat it," he says. "So if we're going to start building more council houses, let's do it properly!"


Passivhauses are super-insulated to reduce heat loss through the walls and roof. They also use triple glazing for the same reason.

The homes are made airtight by means of an airtight membrane in the walls, to reduce draughts and air leakage.

Air is circulated around the house mechanically, using a system known as mechanical ventilation and heat recovery (MVHR). This is controlled from an MVHR unit in the heart of the house (it looks a little like a boiler).

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The mechanical ventilation and heat recovery (MVHR) system in Tim and JJ Shepherd's home

There are ventilation units around the house. The MVHR draws fresh air in from outside, then circulates it about the house, before expelling stale air. The heat from the stale air is recaptured before it is expelled, helping to keep the house warm.

Fresh air drawn in from outside is filtered as it comes in, removing dust and even pollen grains. This gives the air inside passivhauses a wonderfully fresh smell, and means it is good for people with asthma or allergic conditions such as hayfever.

To be certified as a passivhaus, a building has to undergo a rigorous testing process - including checking how much air leakage there is. No more than 60 per cent (0.6) of the total air volume of the house is allowed to leak out in any one hour. In a conventional house, this is more like 500 per cent (five times the volume of air in the house) each hour.

Houses do not need to be equipped with solar panels to qualify as a passivhaus. But a passivhaus that does have solar panels on the roof will have heating and fuel bills that are next to nothing.

The passivhaus was the brainchild of Bo Adamson of Lund University in Sweden and Wolfgand Feist of the Institute for Housing and the Environment in Germany. The first-ever passivhauses formed a row of four terraced homes in Darmstadt, Germany, and were completed in 1990.

There are now thought to be about 30,000 passivhauses in the world.

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