The home of tomorrow seems likely to look little different than today. Buyers are notoriously conservative - as shown by the similarity of today's homes to those occupied by our grandparents. Glass and steel boxes were being built more than half a century ago but have never caught the public imagination.
When the UK National House Building Council organised a Home of the Future exhibition, a wide variety of high-tech designs emerged. But the central property looked identical to any traditional, stone-built home in a pre-war suburb. In fact, the NHBC demanded that designers followed this brief, convinced that it will be the continuing preference of homebuyers in the next century.
Under the skin, however, the house pointed very much to the future. It was highly energy-efficient and the doors and stairs extra-wide, allowing for pushchairs or wheelchairs. The home of tomorrow will cater for a family which buys and stays through all the stages of child-rearing and elderly infirmity rather than moving.
Houses change through evolution rather than revolution. Even the most basic homes will have more comprehensive facilities in the next century, says Mr Pretty. All the so-called luxuries now found in larger homes such as en-suite bathrooms and utility rooms will be considered standard.
Home offices will become another fixture as work patterns change, but buyers will not swallow them today. They will demand a garage instead, says Mr Pretty. But demand for car spaces will fall as transport becomes more restricted in towns. And owners will not necessarily move out of large family houses as their children grow up and leave. They may turn bedrooms to other uses, such as hobby rooms, or studies.
There is potential for compromise, however. Duncan Baker Brown and his colleague Ian McKay won an award from the Royal Institute of British Architects for the Futurehome they designed at the exhibition. It looked more futuristic than some competitors but was built in traditional - and sustainable - resources like brick and timber. It was important to produce something "buildable" by ordinary craftsmen, says Mr Baker Brown. Many proposals for the future would destroy the trade.
The home of tomorrow should be going up today. One in five children has asthma, so all homes should be low on pollutants. They should be equipped for work - not just to save the environment, but also the family. Baker Brown and McKay say their designs are feasible in an ordinary inner city terraced home.
Houses should certainly be bigger in the next century. Builders are currently forced to cram sites because land prices are so high. Releasing more would cut values enough to reverse the trend. Mr Pretty also sees changes in homes as governments switch resources to public transport by the next century. Builders will no longer have to include the obligatory garage or parking spaces, allowing more space within homes
Underlying all this is the fact that most people will own their home, although the housing market will be quite unlike the pattern of today. Government subsidies for ownership are likely to shrink to insignificance, says the UK Council of Mortgage Lenders. Inflation and interest rates will also remain suppressed. Debts, however, will be higher in relation to income and so will levels of mortgage repossessions. Owners will no longer work on the assumption that house prices always rise.
Despite these changes, owner-occupation should remain strong. Some 85 per cent of adults expect to own a home in 10 years compared with today's ownership level of 68 per cent. Despite the latest slump, most youngsters also aspire to own a home.
These figures should be treated carefully however. Expecting to own a home and actually getting one are two different things. Mr Humber believes ownership will peak at around 70 per cent. If inflation continues to remain low, renting will become far more important because capital gains on property will not be as significant, says Trevor Moross, vice-president of the British Property Federation and managing director of the residential property company Dorrington Investments.
Some housing will not last the pace, however. By the next century we will have to be seriously considering replacement of stock built over the last 50 years, says Tim Cann of international property consultants Chesterton. This will give extra space to build new inner city homes.
Around 40 per cent of the population will be at or above retirement age by the year 2000. Many will need housing to suite their special needs and, leaving old homes which again will provide the opportunity for clearance.