Eco-friendly properties are all the rage, but a new-generation concept house in Denmark takes things a step further, producing more energy than it consumes. Built just outside Aarhus it is a sleek, angular building which looks more like a stealth bomber than a family home. But it is a remarkable building - the world's first "Active House". It is a home so environmentally friendly that it produces more energy that the four occupants can use. In fact, so much surplus energy is created and fed back to the national grid that in 40 years' time the house will have produced more energy than it consumed in its construction and so will have completely cancelled out its carbon debt to the planet. bearing in mind tha 40% of energy consumption in industrialised nations is attributed to buildings, this is a truly groundbreaking scheme.

Inspired by VKR Holding

"Active House" is the brainchild of the company best known for making Velux Skylights and Velfac Windows and was produced in collaboration with Esbensen Consulting Engineers and Aart Architects. Completed in April 2009, after years of planning and designing and six months building on-site, the house was at first opened to the public for tours. Now it is being lived in for 12 months by a family of four while its performance is monitored.

I went on a tour of the house, which has a floor area of 190m² back in April and was amazed at the huge sheets of glass - double and tripled glazed, argon-filled windows. Approximately 40% of the walls of the house are windows. This must be twice as much as an avergae house - it seems more when you are inside. It makes the "Active House" very different to other eco-friendly houses in which windows are built into south facing walls to benefit from energy from the sun but are rarely seen on the other aspects, especially northern walls.

If the designers of the Active House wanted to give it a superior quality of light then they succeeded. I loved it for the light - I want to buy or build an eco-friendly house to leave to my grandchildren - hence my interest.

Pitched Roof and Use of Slate

The pitched roof is key to the energy collection. The southern aspect has 50m² of solar cells which genrate electricity and 6.7m² of solar collectors for hot water. The deep pitch on the northern side means that the maximum amount of roof space faces south and at the best angle for solar panels. I usually find that soalr panels look out of place on buildings - this was the first example I had seen in which they fit seemlessly with the rest of the façade. The walls and roof are covered in slate which blends in well with the colour of solar panels. There are two other eco-friendly advantages in using slate : it consumes less energy in its production than brick and is very easy to maintain.

Solar Collectors

For eight months of the year the solar cells produce excess energy from a renewable source. This is sold to the national grid, and in the winter any additional energy needs are simply bought back. The solar collectors provide 50% - 60% of the household's annual hot water needs, supplemented by an electric water pump and a heat transfer system. This system extracts heat from the air leaving the building and uses it to warm the air which enters the house.

All of these systems are automated via a futuristic touch screen control panel which is set in the entrance hall. There's a computer linked to a thermostat which controls the interior climate by opening and closing windows, operating internal and external blinds and switching lights off when a room is not occupied. It is a very user friendly system - even the most computer-phobic person (on our visit my sister-in-law) can operate it after a short lesson. There is an override switch if you feel like being rebellious !

Nothing Monastic About the Interior !

The house has two flat-screened televisions, a kitchen equipped with Siemens and Gaggenau appliances, a double shower encased in trendy recycled glass tiles and a washing machine. The only concession to home comforts is the lack of a tumble dryer - the monster of all energy consuming appliances - but there is a covered clothes hanging area outside.

The technology and engineering behind the Active House is extremely complicated and the cost of creating a bespoke system pushed the final costs to almost €600,000. But as a prototype this project showcases how successfully new technologies can be incorporated into attractive and comfortable buildings in a serious and forward-thinking attempt to tackle the energy issues.

Domestic architects are already changing their focus from the expressive, iconic styles of the last 15 years. Increasingly they want to integrate new technology with designs that connect with and make the most of the natural environment.

Seven more Active Houses are planned - hopefully to be built across Europe next year, including Germany, France, Austria and the UK. They, like the house we visited near Aarhus, will be showhouses for the public to explore and to learn.

This house is costs about three times what I have to spend - but the visit showed us the possibilities available on a smaller budget. Also, Aarhus is a lovely city !

More About Eco-Friendly Houses :

I've been doing some research as we are fired up to visit more eco-friendly houses.  As things stand, most are outside our budget to buy in their completed state. However, as we have a plot of land with planning permission - we are visiting to look for ideas.  Just thought I'd share a few more examples of eco-houses here - I'm not on of the estate agents mentioned - but I can say that all these agencies have been very helpful when I called them.

This is a house that we want to visit - it is in northern France, so convenient for the UK and is just, almost, at a stratch within our budget.

It is in a village location - Manche, about 200kms west of Paris. It has 3 bedrooms and is the first "Earthship" (a concept for eco-houses that originated in the US) to be built in Europe.

Constructed partly from recycled materials, it is completely self-sufficient, producing energy from solar panels and a wind turbine. Water collected from the roof is filtered to drinking standard and food can be grown in the large greenhouse corridor that runs along the front of the house.

It's on sale for €285,000 with IBS Immobilier

I feel a journey to France coming on ......

This one is above our budget - but we are going to visit it as it is in the UK - about 4 hours drive from Kent, but we'll find a nice B&B for a night's stop over.

This is one of 5 pioneering eco-homes currently being built by Ecos Homes in the rural village of Stawell, near Bristol.

The homes combine stylish contemporary living with sustainable technologies such as solar panels and wodd-pellet stoves. The landscaped gardens include allotment space to grow your own fruit and vegetables as well asthe facility for shared access to an electric car pool !

Three-bedroomed terraces start at €322,000 and four-bedroomed detached houses at €399,000 - more details through Ecos Homes

This one is waaaaaaaaaaaaaaaaaaaay above our budget - but the site is worth a visit if you are interested in eco-homes. This could also be a great luxury holiday let investment.

The villas are situated at the AlmaVerde Village & Spa complex in the Western Algarve, an hour's drive from Faro airport. They combine spacious living with an impressive array of eco features. Built in an environmentally protected area, the homes include high levels of insulation, double glazing, solar-controlled windows, internal walls made from sun-dried clay and an innovative green ventilation system that helps to heat and cool the home.

The three bedroomed villa in the photographs is on sale at €733,000 from AlmaVerde Village & Spa