by Anna Lindsay
BBC iCan reporter, Oxford
Solar panels sit on top of the eco-friendly Yellow House
When George Marshall decided to move house he had a vision.
Passionate about the effects of climate change, he wanted to create an eco-friendly home that was warm, bright, clean and cosy.
No hippy communes, no wood shacks, not a glass 'pod' home in sight.
So he set about converting a run-down, former council house in Oxford and has seen his energy bills go down by 60% - something, he says, everyone should be trying to achieve.
"I moved to this house about four years ago and it really was in a bad state," Mr Marshall, who runs an environmental group and website, told the BBC.
"My wife Annie and I thought it would be great that if we had to do it up, to do it to a really high environmental standard."
An array of solar tubes now sits on top of the bright yellow building, which, even on an overcast day, provides the couple and their two young children with half or more of their hot water needs.
Top-of-the-range insulation surrounds the external walls and wood, instead of UPVC, frames the high-performance windows.
George Marshall "loves" his grass roof that overlooks a sun porch
At the back of the house, a grass roof overlooks a sun porch.
"I love grass roofs. I think it would be great to live in a world where there was just grass and green things as far as you could see, where there wasn't any concrete and tiles."
Much of the home's interior is built from salvaged goods; the kitchen is made entirely of 1940s and 50s oak units found in junk shops.
"I don't like fitted kitchens," Mr Marshall says.
"They are extremely wasteful because they are often very badly made and fall apart in a few years.
'Pester my neighbours'
"Our kitchen is made of good quality oak, with proper dove-tailed fittings and cost us just £120.
"The toilets and sink are also all from local salvage yards. Our clock, which has Royal Mail on it, is from an old post office and the sink upstairs is an old medical sink from a hospital."
The kitchen is made entirely of salvaged units from junk shops
The couple's energy costs immediately dropped by 50% and have continued to fall.
"I pester my neighbours here on the estate and they've given me all of their fuel bills so I have an idea of how the house is comparing with others," Mr Marshall said.
"Every one of these houses is identical so I can draw comparisons and I know that this house is enormously economical - it saves us money but it is also good for the planet.
"The government is saying that in order to stop climate change, which is getting really bad now, we're going to have to reduce our energy consumption by 60%.
"In other words, if we're going to meet that target, every house is going to have to be like this one."