Imagine telephoning your bathtub from the office and having it filled with water at the right temperature and depth by the time you arrive home.

It may sound like science fiction, but this is exactly what Bill Gates can do as he drives back to his country house from the Microsoft headquarters in Redmond, Washington.

Although this kind of technology may be available only to a man of Gates?s pockets, buyers can do much to ensure that the home they settle for does not become obsolete in five years? time. A good rule of thumb is to allow for what you need now as well as what you think you may need later, because retro-fitting your home will turn out to be a far more expensive job than future-proofing it at building stage.

?The most important thing is to pre-wire with cabling for voice and data distribution before the walls are closed and the plastering is done. You can make a decision later on the type of equipment you want,? says Steven Worrell, director of Smartcomm (+44 01494 471 912), a company which custom installs home automation solutions in commercial and residential properties.

The most obvious requirement is to add wiring for a fast web connection. ?Broadband makes houses easier to sell as more and more people demand it,? according to Ian Perry, RICS housing spokesman for England and Wales.

Once you have broadband, a small investment in a laptop and a wireless station ? a device that enables internet connections across a 30m to 50m radius area ? will allow you to go online from any room without the need for cables.

The power of computers is also transforming white goods into intelligent appliances, such as Merloni?s new Smart Cooking oven which downloads recipes from an online repository.

If this much is happening in the kitchen, the living room is positively buzzing with innovation. A good home theatre system, which re-creates a cinema-like experience, is the minimum requisite for a house that is to withstand the test of time. Video facilities can range from a humble television set to a 60in plasma screen or even a projector for a purpose-built cinema room. But no entertainment set-up would be complete without a surround-sound system where five loudspeakers (three in the front of the viewing area and two at the sides) allow sounds to flow from all directions.

Buyers looking to future-proof their house should also look at other fundamental, if more mundane, devices. High-security iris scanners that automatically identify owners by their eyes and unlock the front door may yet be unavailable outside a test home at the Microsoft compound in Redmond, Washington, but surveillance systems have become increasingly high tech.

They will automatically alert you via telephone, email or text message if the alarm goes off, or even send to your laptop a streaming video of what is going on inside your house at any time.

At the upper end of the scale, integrated systems can co-ordinate security with lighting, heating, audio and video, which can all be controlled by one touchpad screen or remotely be telephone.

Or example, lights can be programmed to switch on throughout the house if the alarm rings, room temperatures can be set remotely via the web, or by mobile phone ? useful when you are coming back from holiday ? and lights can be adjusted to the required brightness to suit your home theatre screen.

Should all this not be enough, there are even windows made with a smart glass that lets in only as much heat and sunlight as you need.

?Lighting control sounds like a toy but it really changes the feel of a house. It has different light settings depending on whether you are watching TV, reading a book, or having a party,? says Stephen Gough of custom installer Hometech (+44 01355 272798) and Chairman of CEDIA, a trade association of home automation companies. ?Some systems will even record your lighting habits throughout the house and replay them for up to two weeks while you are away so it looks like there is someone there at all times.?

Health and fitness are the last frontiers of home innovation. Indoor gyms, spa baths and power showers are now fairly commonplace, but it is now easy to turn a shower into a Turkish bath with a steam generator or install a portable sauna, which can be bought ready-made and set up in the spare room within minutes.

This article was originally printed in COUNTRY LIFE magazine, in the property supplement on April 29, 2004