Combination Boilers are now the best selling boiler type for gas central heating in Britain. They've been proven steadfast, reliable and tough.

Some combis will settle snugly into an average cupboard.They are economical to run. And can certainly produce an endless supply of hot water. There is no storage cylinder to heat first or to run cold. There will be no cold water storage tank to find space for and no feed and expansion tank needed.

Around one quarter of Britain's carbon monoxide emissions originate every year from the the energy we use to heat and light our homes. It's because we burn fossil fuels (gas) to produce that energy. And over time the resulting waste gases do add to the effect of global warming.

A conventional system has two water tanks in the loft, a large ‘cold water storage tank’ and small ‘feed and expansion tank’. The ‘cold water storage tank’ draws water from the cold water mains to refill. The central heating boiler will heat the cylinder and converts cold water to hot, this then enables the cylinder to release gallons of hot water to taps throughout the house. The ‘feed and expansion tank’ is usually smaller and maintains the correct level of water in the heating system. It also allows for expansion of the water in the radiators and pipework when it gets hot. A real benefit of this system is that showers, taps and running baths can be drawn in any room at the same time; not all systems can do that.

To a degree just changing an older style boiler to a new conventional or combination boiler (around 80% efficient) is a big step in the right direction, any boiler over 15 years old is inefficient (approximately 50% efficient), wasting natural resources and your money. But if you feel that you want to make a positive statement; you'd like to really reduce emissions and your gas bill you may want to consider a 'High Efficiency Condensing Boiler' (around 91% efficient). Yes it is a little more expensive initially. But you'll gain in the long term when you notice that your fuel bill has been reduced substantially. In some homes more than one third.