heating & hot water

Now perhaps those factual statements above surprise you. But there are many myths surrounding central heating and hot water - and how to get the best from both at a reasonable cost. So let's begin with the first myth.

Many years ago a 'decent' shower was to be had by a 6 kilowatt shower. But summer holidays in European hotels woke people up to better-performing showers, faster flowing water, and hot as well. Anyone who's ever been to a camping site will know just how poor showers can be.

It was only around the late 1980s that manufacturers began to offer ever-more powerful electric showers. Because if you up the electric from 6 kilowatt to 9 kilowatt then it allows more water to be heated - and therefore a greater flow. It's now possible to buy a 10.5 kilowatt electric shower. And modern ones come with comfort controls that allow you to thermostatically set your shower to exactly how you like it - even if someone opens a kitchen tap while you're showering!

Electricity costs around 10p per kilowatt. So a 9 kilowatt shower (that's 9 kilowatt hours, or kWh) costs nine times that for one hour, or about 90p. Now unless your teenage daughter would actually spend an hour in the shower then you don't have to worry about 90p every time she disappears into the bathroom with a towel, because the average shower is just four minutes. So the figures are 90p divided by 60 minutes, multiplied by 4 minutes = 6p.

An electric shower really is a very cheap way to heat hot water. This is simply because you are only heating the water you need. In the past, electric showers suffered from limescale build-up. However, there are now three limescale inhibitors available on the market that will eliminate this problem from around 13p a day.

Heating only the water you need has been very popular for some years now with heating boilers also. So-called combination, or 'combi', boilers have sales figures that now outstrip conventional heating boilers. A Combi boiler combines heating and hot water in one appliance. They are certainly more economical on actual gas used, though some have proven to be unreliable and expensive to maintain. That, limescale build-up, and an inability to provide copious amounts of hot water have given combi boilers rather a bad name.

As with electric showers, the limescale problem can be totally eliminated. Also, there are combi boilers that can provide huge amounts of hot water on demand. The problem is that installers have tended to fit the cheaper combi boilers whose hot water provision is only ever adequate for a single person, not a family.

The problem over unreliability is simply down to inherent designs. Modern gas boilers are expected to safeguard themselves, switch themselves on and off, and blow their fumes out of a small tube. All this and more has meant that devices have had to be fitted. But more complicated designs and devices almost always means less reliability. And so it has come to pass with 'condensing' combination boilers. It became law in April 2005 that you have to one whether you like it or not. It's only possible to have a conventional boiler if your property is deemed (by a points system) unsuitable for a condensing boiler.