Now you see it, now you don’t: windows that become cloudy and private at the flick of a switch show how amazing glass around the home can be in the 21st century.
The panes that play misty for you are made by Blink Glass (www.blinkglass.com). It sandwiches glass with a filling of liquid-crystal polymers that is wired to an electricity supply. When "off" the glass is see-through; flick the switch and it all frosts over, doing away with the need for curtains or blinds.
In a bedroom, such glass could allow you to have a fashionable and open-plan en-suite, giving a greater feeling of light and space to a small room.
At the flick of a switch you can "hide" the bathroom completely. Or in a kitchen/diner you can cover up the cooking chaos when the dinner party guests arrive.
Today, glass is the magic material of modern buildings. Londoners are loving the light it can bring into dark, cramped homes.
Cantifix (020 8203 9203; www.cantifixonline.com), a family firm in Hendon, north London, works with Blink and specialises in sophisticated glass installations. And it’s doing well - business is 20 per cent up on last year.
"Glass floors or big panels are just brilliant for basements," says director Charlie Sharman. A new glass called Floor Glaze can be used in huge chunks but, unlike before, it now meets fire-regulation standards.
Also new is Nano Gel, which can fill the gap in double glazing. "This material is an incredibly good insulator," explains Sharman, "and large panels of glass can be as energy efficient as a conventional wall."
Glass is also a trusty eco-friend, made mainly from sand, an abundant natural resource, or better still from old glass, which can be recycled time and time again.
One company assiduously saving the empties is Bottle Alley Glass (www.bottlealleyglass.co.uk), which creates arty recycled tiles, splashbacks, worktops and lighting in a subtle mix of greens, amber and misty greys.
Also, super-thin glass slivers can be stuck together - or to other materials such as metals or wood. Here the enabler is "UV bonding", where a clear resin is hardened by light for structures that almost hover without a frame.
Sleek shower compartments and glass doors are in one piece with no evident fixings. You can have a good soak in a curvy, laminated and bonded glass bath by Italian makers, Novellini (www.novellini.com). The price of about £10,000 does include taps, shower heads, etc.
However, UV-bonded shower screens on the mass-market start from £600. Or get hot with a glass radiator from about £630 at the Glass Radiator Company (www.glassradiators.co.uk).
A glass staircase is now almost de rigueur for modern architecture and interior design. "They have a light, ethereal aesthetic and seem to float, thanks to modern engineering," says Richard McLane of staircase specialists Bisca (www.bisca.co.uk). Prices start at about £20,000.
For safety, everything must conform to stringent building regulations and it is essential to use a specialist.
Add captivating colour and tactile texture and glass leaps into life. Digital printing can put artwork and even photographs on to shower cubicles, table tops, screens and windows.
Or a generous one-piece translucent glass "sandwich" can be filled with fabric, thin slivers of stone, leaves and grasses, or even, it seems, slivers of vegetables. That was a commission for Fusion Glass (www.fusionglass.co.uk), whose showroom in Clapham is a veritable glass paradise. Screens or tiles can glow within from tiny, embedded fail-safe LED lights.
Or you could go to Ion Glass (0845 658 9988), near Brighton. Explore web page after page of inspirational past design commissions on www.ionglass.co.uk. You can commission "back-painted" glass in sheets of any colour, or go for a multi-coloured glass washbasin.
London is rich in glass artists. While obviously adept at vases, platters and goblets, they also put exquisite glass into buildings as wall panels (often lit), balustrades, screens or fitted into windows.
Track one down through www.designnation.co.uk, www.craftscouncil.org.uk or www.hiddenart.com, who can all help with commissioning.
For the environmentally minded, a simple new tool called the carbon calculator works out heating savings from the installation of advanced types of energy-efficient windows, which are now rated, like appliances, from A (the best) to G. Check it out through the Glass and Glazing Federation on www.ggf.co.uk. It can also supply a list of approved installers.