Could this green home be a new model for mass build?

When The Prince of Wales decided to visit a showcase for eco-homes in a park on the edge of London one can only imagine the sense of anticipation among his hosts. The Prince is an organic farming pioneer whom Time magazine once named a “hero of the environment” and he cheerfully describes climate change deniers as “the headless chicken brigade”.

Alas, for the people at the Building Research Establishment’s Innovation Park in Watford, Hertfordshire, The Prince’s appetite for greenery did not extend to their eco-buildings.

“He really didn’t like what he saw,” says BRE spokeswoman Linda McKeown, as she shows House & Home one of the buildings that caught The Prince’s eye during his visit, not long after the park opened in 2005.

It is an asymmetric house clad in wood and recycled plastic slates, with solar panels and enough smart wiring inside to monitor energy consumption and manage an on-site car club. “He said he was going to get The Prince’s Foundation to come up with an alternative,” says McKeown.

This was duly done and the result is just metres away: The Prince’s Natural House, a Regency-style white two-storey villa divided into a three-bedroom house on one side, and two apartments on the other, with a clay-tiled roof, cast-iron railings, the odd column and a wild flower garden.

Developed by The Prince’s Foundation for Building Community, the house is a picture of traditional restraint compared with the more adventurous modernism of its neighbours. It does, however, share their aim of minimising environmental impact. The roof has been insulated with sheep’s wool. The walls are made of clay blocks with air pockets, which are better at blocking out heat and cold than conventional bricks. They are rendered in lime and hemp, natural alternatives to concrete.

Inside, large, triple-glazed windows block the roar of the nearby M1 motorway to good effect. The interior decoration is more Country Life than Vogue Living, with solid wood cupboards, slate bench-tops and a minimum of stainless steel. There is a wood-burning stove, wall heaters, wool carpets and, in the kitchen, the one hint of the Natural House’s royal sponsor: a set of commemorative mugs, including one for The Prince’s 1981 wedding to Lady Diana Spencer.

A passive ventilation system can automatically let in more or less air, according to humidity levels, but that is about it when it comes to the gadgetry that is a feature of many eco-homes. As The Prince said just after the house was completed in 2011, it does not have “eco-bling”, by which he meant solar panels, wind turbines or other high-tech add-ons.

Instead, the idea was to build it from natural materials, grown in the ground or taken from the ground, and design it in a way that would attract people who like the notion of an energy-efficient home, but are averse to more modern designs.

As the former housing minister Grant Shapps put it at the Natural House’s opening, the result is a contrast to Scandinavian-style dwellings, “wearing their green credentials for all to see”.

Like The Prince’s eco-friendly Poundbury village in Dorset, the Natural House has had its detractors among less traditionally minded architects. Some hail the use of natural materials but say it is wrong to treat solar panels and smart technology as mere add-ons when they can put a dent in energy use. That is all very well, says Constantine Innemée, spokesman for The Prince’s Foundation for Building Community, “but if you have gadgets that break or are unused, that theory doesn’t hold up”.

So what is the Natural House actually like to live in?

Cosmin Ticleanu, a lighting engineer at the BRE, spent a year in it with his partner until last summer and reports that “it was a very good experience”. The lighting could have been brighter in spots, and sometimes the ventilation system had to be manually overridden. Still, he adds, it was comfortable, liveable and had a “good, homely feeling”.

The BRE’s McKeown says the house has attracted substantial interest among the 60,000-odd people who have visited the Innovation Park since its inception. It has yet to be widely copied by mass-volume home builders. However, builders are using the air-pocketed clay bricks in some homes, says the house’s architect, Ben Bolgar, senior director at The Prince’s Foundation for Building Community.

One key feature now more widely used since the house was built, he says, is its “fabric-first” approach, where the walls, floors and roof are made to be as resilient and high performance as possible, rather than using cheaper versions and then adding solar panels and other equipment to improve its environmental impact.

The building can be constructed for just under £280,000. A volume housebuilder can build more cheaply, says Bolgar, “but we feel the flexibility and attraction of this home would be very good value for the right sites.” While the house has not been rated under the code for sustainable homes – a national standard that uses a one to six-star system (six being the highest ranking) to rate a home’s sustainability – he adds it is roughly equal to a rating of between three and four.

“Its biggest contribution is [to show] that sustainability can be beautiful and simple,” says Bolgar.

Pilita Clark is the FT’s environment correspondent