Imagine a flat-pack house that won't cost a penny to heat or light and that can even charge your electric car for free.
A new zero-carbon show home that's been built at the BRE Innovation Park in Watford offers just that for only £129,600.
Zedfactory's Zero Bills house can make and store all the electricity it needs from a solar-panelled roof and energy storage system - saving the average householder £1,300 on home energy bills and £1,000 on fuel for the car.
It's heated by a small air source heat pump that recovers heat from stale air and recycles it, and spare energy's stored in a battery system under the stairs.
The house comes as a kit of parts, based on a steel frame with timber wall panels, most of which is manufactured in the UK. It costs £1,350 per square meter, says the firm, and is quick and easy to build with.
"With its integrated energy generation facility it shows how we could actually reduce the investment needed for centralised national infrastructure by becoming net exporters of renewable energy," says Zedfactory founder Bill Dunster.
The first Zero Bills homes are now waiting for planning permission in Newport, Essex.
Many zero-energy homes exist around the world - best known, perhaps, are those built to Germany's Passivhaus specifications.
Last summer, a team at Cardiff University developed a zero-energy home that took just 16 weeks to construct and cost £1,000 per square metre. While it will need to buy in energy during the winter, say the designers, it will produce more than it needs in the summer - meaning it will actually produce more than it uses overall.
Back in 2006, the then chancellor, Gordon Brown, pledged to make all new UK homes carbon neutral from this year. All new dwellings would have had to generate as much renewable energy on-site as they used in heating, hot water, lighting and ventilation.
However, last summer, the government axed the plans, saying it wanted to make life easier for building firms.
Julie Hirigoyen, chief executive of the UK Green Building Council, described the move as 'short-sighted, unnecessary, retrograde and damaging to the house-building industry'.