The report, by researchers at Oxford University’s Environmental Change Institute, UMIST and Heriot-Watt University, outlines a "plausible technology route" to achieve a 60% reduction in emissions from the housing stock.
Households account for around 30% of the UK’s total energy use. The report concludes that there is a "desperate need" to bring housing and energy policy together into a clear strategy.
The researchers assess the prospects for over 20,000 different types of homes by 2050, and consider issues such as demolition rates, population growth and house occupancy. Their main proposals are:
The report recommends that some 3.2 million of the least efficient current homes should be demolished by 2050 - 14% of the current stock. Listed buildings would be spared, but the plan would quadruple the demolition rate by 2016.
The Government is planning to allow hundreds of thousands of new houses to be built, almost half of them in the South East. In late March, Ministers confirmed that from April 2006 all publicly-funded new homes - including 120,000 planned for the Thames Gateway - will comply with a code for sustainable buildings, due to be released in a few months (ENDS Report 355, pp 54-55 ).
The report recognises the need to construct some 10 million new homes by 2050. However, it expects those built from 2020 to have virtually no demand for space heating.
Even so, over two-thirds of the 2050 housing stock has already been built and needs to be made more efficient. The immediate priority is for all wall cavities and lofts to be insulated. By 2050, the report says, 15% of solid walls will also have been insulated and all windows will be "high performance" - with double, or even triple, glazing.
These changes to the housing stock should reduce total space heating requirements by 38% from 1996 levels by 2050 - despite a 33% increase in the number of households.
Optimistically, the report assumes no need for domestic air conditioning because homes will be designed to keep cool in summer by shading, insulation and thermal mass. Without such design measures, rising temperatures due to climate change could lead to air conditioning in 29% of homes in southern England by 2050 - blowing a hole through the whole plan.
Reversing this trend will be "a considerable challenge" given the forces leading to increased consumption, the report says.
EU energy labels helped cut the energy consumption of a typical fridge by 29% between 1990 and 2001 - though the report says the impact has been limited by the failure to set tough minimum efficiency standards. The EU is now relying heavily on voluntary agreements, such as an industry commitment to reduce standby energy use for audio goods.
"If significant savings are to be achieved then a stronger approach is essential," the report says. The Government, the Energy Saving Trust and the Carbon Trust need to identify promising technologies and support their introduction to market.
The report highlights vacuum-insulated panels in cold appliances which can halve electricity use. This technology has been available for more than a decade, but has been held back by weak efficiency standards. The researchers advocate a standard to halve consumption from 2015, which should result in 100% adoption of vacuum panels by 2050.
Another example is light emitting diodes (LEDs), currently used in bicycle lights, advertising and traffic lights. LEDs could be available for domestic lighting from 2015, offering an efficiency 50% higher than compact fluorescent lamps.
The report assumes that by 2050 the full technological potential is achieved for lighting and all appliances. This tall order would cut the energy use by 44% for each house, or by 27% across the expanded housing stock. The report also assumes that the trend for increasing numbers of appliances will be curbed.
By 2050, the researchers expect about two installations per household - enough to meet all household electricity demand, and 82% of demand for warmth and hot water. Common technologies expected are solar hot water, photovoltaics, community heating and micro combined heat and power (see table).
At the report’s launch, David Strong of the Building Research Establishment had "grave reservations" about relying on micro-CHP. "The jury is still very firmly out" over whether units based on Stirling engines will prove technically or economically viable, he said, while designs based on fuel cells are still "science fiction".
Co-author Marcus Newborough of Heriot-Watt University replied that the scenario is not technology-dependent - if micro-CHP fails, other technologies could make up the gap.
However, making the residential sector more self-sufficient would reduce winter peak demand by some 25GW. Much depends on utilities offering energy services packages, which combine energy supplies with low and zero carbon technologies and energy efficiency measures.
Making energy services more attractive to suppliers "represents a challenge for Government, with Ofgem a key player", the report acknowledges. The energy regulator is currently overseeing a two-year trial of the market for energy services (ENDS Report 347, pp 49-50 ), and in March Npower became the first major supplier to offer such a tariff.