Just don't go throwing stones

Boiling hot in summer, freezing cold in winter and open for all to see, glass houses are not everyone's idea of fun - but new advances in glass technology could soon make them a favourite. Lesley Gillilan reports

To Describe an architect's house as "a box" is possibly the ultimate denigration, but Jonathan Ellis-Miller won't mind if I allude to his rural Cambridgeshire bolt hole thus, as long as I clarify that it is a stylish, steel-trained glass box, not a formless brick one. Flat-roofed, low-slung and topped with a little metallic chimney, the Ellis-Miller house is a homage to minimalism. And glass - an entire wall of the stuff - is its defining material.

The best thing about living in glass houses, he says, is that "you get the benefit of the outside world - it blurs the boundaries between interior and exterior spaces." The rear wall features a band of glass set below eye level (he didn't want to see the "gross-looking" house on the other side of the garden hedge), but the front of Ellis-Miller's home is a sheet of double glazing providing a window over the earthy flats and big windy skies of its Fenland setting.

When he built the house in 1988 (for less than pounds 50,000) he chose the site in the village of Prickwillow because it offered a view of Ely Cathedral. Trees, weather and passing neighbours provide an animated aspect to his living external wallpaper. The house benefits from an abundance of natural light and - when the glass is slid open - country air laden with hints of livestock and lavender.

One of the worst things about living in glass houses, he admits, is their transparency. Hence mechanically operated external Venetian blinds - "20th-century net curtains" - are an integral element of Ellis-Miller's structure. The fact that his view is striped with metal is compensated by the bars of light and shade cast on to the pristine white walls of his west-facing, open-plan space. But voyeurs can still peer through the slats and catch glimpses of chrome and black leather, the glow of a log fire and Hector - a Dalmatian who recently came into his own as a fashion accessory when the house was used as a set for the BBC's The Clothes Show.

At night, when the house becomes an illuminated cube, its contents are as tantalisingly visible as merchandise in a shop window. That's not too much of a problem in a sparsely populated backwater like Prickwillow, but move the house into high-density urban area and it would be like living in a goldfish bowl. The alternative for glass-house dwellers is to insulate your private life behind closed blinds.

Ellis-Miller's blinds would be closed less often if he didn't live next to a road, he says, but, aside from a few compromises, the house has proved "appropriate in every way" to the landscape and his lifestyle. Whether anyone else will find it so will be put to the test when Ellis-Miller puts the one-bedroom house on the market later this month. Me thinks he couldn't live with selling it to anyone who might clutter his design statement with Dralon sofas or, worse, flowery curtains, but, whoever the buyer, he is determined to move on.

He designed his home, aged 25, because fellow designer and mentor, John Winter, told him he'd never be a proper architect until he'd built his own house. "I created an icon," he says. "But I no longer want to have my life and my career defined by the first piece of architecture I ever did."

Rising young architects often design personal projects as a way of exercising their creative muscles, inviting polemic and drawing attention to themselves. The modernisers among them have left behind a trail of light, transparent structures scattered thinly, but memorably, throughout the history of 20th-century architecture.

The trend for generously glazed buildings started in Europe in the Twenties with industrial works by Ludwig Mies van der Rohe, Walter Gropius and Le Corbusier. Pre-war Modern Movement houses featured glassy stairwells and big picture windows, but the iconographic all-glass living space actually emerged in America some 20 years later.

In 1945, Charles and Ray Eames constructed a glass and steel dwelling as part of a series of Californian Case Study prototypes. Mies van der Rohe's "less is more" floating rectangular box of glass and white-painted steel, built in Illinois for Edith Farnsworth, appeared in 1946. And in 1949, Philip Johnson designed a 1,800 square-foot house entirely from slabs of glass. Set in the midst of Johnson's own New Canaan woodland in Connecticut it was described by a colleague as, "less like a house than like a diagram drawn in the air to indicate a quantity of space."

As Ellis-Miller's house testifies, these classic glass essays are still influencing contemporary architects, but in Britain it is more difficult to find uncrowded spaces suited to transparent living or, indeed, to win the support of planners - especially now that building regulations are more geared to energy saving. "Most existing glass houses are intrinsically rather leaky in terms of energy," says Michael Wigginton, Professor of Architecture at Plymouth University. Bog standard glass is highly responsive to temperate change and a poor insulator, and the owners of early glass houses have had to pay for their fabulous views in gas bills and, while convening with nature, they are chucking out an awful lot of carbon dioxide.

John Winter, who still lives in the glassy house he built in north London in 1969, believes his house would not get planning consent or comply with building regulations if he was to try building it now. It is double glazed and sits behind a bank of trees which act as a natural sun screen during hot weather, but it is not, he admits, quite as sophisticated as glass structures of the Ellis-Miller generation.

Low emissivity, or Low-E, glass - which reduces heat loss - has improved the thermal efficiency of the reborn glass house. The inexpensive steel- framed box of light designed 10 years ago by architects Vivien Fowler and Tom Jestico in Putney, south London, is a case in point. Their self-built home faces south to harness solar energy, is screened from prying eyes by a walled garden setting, is mounted on a timber platform, and is more energy efficient than many of its predecessors. The house is fitted with internal and external blinds which can be manipulated to control the loss and gain of heat. Although the design won the Eric Lyons Memorial Award in 1992, it only just scraped past building regulations regarding insulation.

Glass efficiency was improved further in 1990 with the launch of Pilkington K Low-E glass - and architect, Michael Axford, reckons he was one of the first to use it extensively when he built his U-shaped, pavilion-like glass house in Avon. A series of free-flowing transparent spaces arranged around an illuminated swimming pool, the design won an RIBA regional award in 1995. Axford and his wife, Julie, talk with enthusiasm about the "quality of light and ever-changing shadows" and the joys of lying in bed watching the night sky or, indeed, rain pattering on the glazed roof. They admit to needing sun-glasses indoors on a bright day, but their energy bills are low for a house of its size.

The most recent, and perhaps most celebrated, of contemporary glass houses is the Glass House in Islington, north London, designed for Debra Hauer, Jeremy King and family by architects, Future Systems. This is not another diaphonous box, but four storeys of glittering glass blocks and aluminium sandwiched between the masonry walls of an end-of-terrace Georgian townhouse and a 19th-century pub. The street-facing elevation is constructed entirely from opaque glass bricks; the rear is a sloping plane of clear, frameless double glazing; glass fire-screens are the only internal partitions, and the split-level living spaces - flooded with natural light via a glass roof - are linked by industrial-look metal staircases.

Solar-heat gain is controlled by manually-operated vents, white fabric blinds and the shade of mature trees. And although the interior of the house may get a little warm on a hot July day, the people inside are unlikely to suffer from seasonal affective disorder (Sad) - a debilitating syndrome caused by lack of natural light.

The house is currently for sale and offers a rare opportunity to invest in an innovative one-off that remarkably won planning consent in an urban conservation area. Though the house met the latest building regulations, published in 1995, it could soon be considered a little old-fashioned in terms of environment control, but like most of the latest glass houses, it will also be regarded as a pioneering design prototype.

At a recent conference in Berlin on solar energy in architecture, Lord Richard Rogers declared glass as "the material of the future", and it's a material that is currently undergoing a technological revolution. A number of innovative new glass products are yet to emerge from the retouch laboratory, but already there's some wonderful stuff on the market which, though hideously expensive, opens up profound possibilities - both functional and aesthetic - for the glassy houses of tomorrow.

Aside from high-performance Low-E glazing, there are glass products on the market which store energy, radiate heat, absorb sound and enable views out at night without mirroring the interior reflection. Pilkington's creation, Mirage, is mirrored on one side and transparent on the other, but when back lit it is totally see-through. Finnish Sologlass produces a coated glass, activated by low-voltage current to prevent heat loss. And Privolite, made by the French company, St Gobain, is a clear glass that turns whitely translucent - rather like a Japanese paper screen - at the flick of a switch. So far, its application is limited to internal partitions, it was famously used in the all-glass cubicles of a unisex toilet in New York.

Further development could make Privolite the net curtain of the 21st century, and it was a major component of an embryonic glass house designed by architects Alford Hall Monaghan Mor-ris for 1994's New British Architecture Exhibition. According to the companion text, the pitched-roofed, transparent Live in Room House "liberates the rooms from their imprisonment and rescues the garden from its status of feeble appendage." It didn't look very convincing as a computer image, but the technology has since been developed to adapt the idea as a structural reality. The architects await the right client.

Structural engineer Tim MacFarlane - referred to by his colleagues as "Mr Glass" - worked on the development of the Live in Room House, and he claims that the technology exists to build an all-glass cathedral. He has already been involved in constructions that use solid glass beams and columns and is experimenting with a material called McKees Fluidised Glazing which not only reduces heat loss but also prevents homes turning into hot-houses without limiting the daylight they receive.

Professor Michael Wigginton is working with Pilkington on a conceptual glass house which he intends to be "a classic work". Still on the drawing board, it's called the Diode and will feature a double-glazed roof, state-of-the-art Low-E glass and electronic insulated louvres which automatically respond to temperate change. "It will be like a lovely flower that closes up at night and opens as soon as the sun shines," he says.

The Diode is designed to harness the energy available from ordinary British daylight, rather than the heat from the sun. "The intention is to exploit the greenhouse effect to our advantage," he says. "But we won't know if the design really works until it's built."

The potential of glass is not restricted to unconventional crystal palaces and machine-made modernist boxes lived in by architects. Estate agent Ian Lange recently built a timber-framed house in Devon which looks like a Medieval barn, except that the oak timbers are inset with large panels of clear Low-E glass.

Another traditional house with a glassy facet will feature at the Ideal Home Show which opens this week (13 March - 6 April). The exhibition's Pilkington K Glass House was not designed by an architect but by society conservatory designer, Charles Frost (Joseph Paxton of Crystal Palace fame was, after all, a gardener to the Duke of Devonshire), and sets out to offer "something to which the ordinary person can aspire" - that is, if they can afford to fork out pounds 175,000.

The show house, which looks tediously mock-period - "almost Tudor", according to Frost - is mainly brick and timber but has a double-height all-glazed structure tacked onto the south side. It won't win any design awards but it demonstrates that all-glass living spaces can help reduce heating bills and create "a happier, healthier home".

This is not the first time the Ideal Home Exhibition has presented a glass house. The last one was sponsored by the Glass Manufacturers' Federation and designed by a student at Liverpool School of Architecture. Constructed from fluted glass bricks, it had a wired glass front door, an illuminated glass and steel staircase, glass mosaic floors, mirrored walls, a sandblasted glass fire-surround and a transparent gas water-heater made from armour-plate glass. That was in 1938 - it takes a long time for good ideas to see the light.

Jonathan Ellis-Miller's Cambridgeshire house is for sale (price on application) through Pavilions of Splendour (0181 348 1234). The agent for the Glass House in Islington is Winkworth (0171 354 2480), details and price available on application.