A pioneering solar-powered north Oxford house will be a model for future "solar cities".

City councillor Susan Roaf's eco-house, in Blandford Avenue -- which is entirely heated and powered by solar panels and a "sun space" air warming conservatory -- is an example of how the homes of the future will look.

So say scientists and energy efficiency experts organising the international Solar Cities conference to be held in Oxford in April.

It will be attended by the mayors of 50 towns, scientists and businessmen, who will gather to discuss action to combat global warming.

The house, which was built 10 years ago, generates enough energy for Ms Roaf to sell electricity to the National Grid. It is a six-bedroom house that produces only 130 kgs of carbon dioxide per annum per square metre as opposed to similar UK houses that produce 5,000 kgs.

Rod Macral, of Solar Cities, said: "The kind of knowledge and technology that exists here in this house is the start of things that will be replicated in solar cities.

"It provides the same kind of reference for any other buildings, houses and businesses."

Ms Roaf said: "My house was the first solar house in Britain and it is a demonstration of the way Oxford has pioneered the solar movement.

"As a result of it, we formed the Solar Initiative and hundreds of houses in Oxford have installed solar heating systems.

"The cost of energy will double and quadruple in decades to come and so will become a necessity for all new housing to be built with solar systems.

"Already the city council has converted houses and bungalows for the elderly so they can save money on their bills."

She said the house did not cost any extra to be built than a normal house.

Green councillors Craig Simmons and Elise Benjamin have been trying to renovate their east Oxford house to make it more energy efficient.

They already have a small solar panel and wind turbine on their roof in Magdalen Road but a planning application for a "sun space" conservatory, which would trap hot air and use it to heat the house, was refused.

Mr Simmons said: "It's rather easier to build from scratch than renovate the existing housing stock, but we can't just knock buildings down and replace them.

"The trouble is making changes as what we have been trying to do is costly and there are barriers such as planning.

"We are very committed, so we spent a lot of time doing the research. The system is just not set up for it."

They are now seeking to put a bigger wind turbine and solar panel on their roof.

Averil Stedeford, 73, is converting her central Headington home to be energy efficient but has also found it to be very expensive.

She said: "I have found it difficult and very costly, but it has already provoked a lot of interest from friends and neighbours and is making them think about doing the same thing."

For more information, visit www.solarcities.org.uk