Time to replace your home's boiler? It can be a daunting prospect, ripping out your central heating, but sometimes it just needs to be done. So how do you go about picking a replacement?

Step one - think about energy efficiency

A boiler that's 15 years old or older is only around 60-70% efficient, meaning that as much as 30-40p of every pound spent on heating and hot water is wasted.

Many older boilers also have a standing pilot light, which can cost around GBP50-GBP60 a year to keep alight. That's a lot of cash spiralling down the drain. Investing in a brand new A-rated condensing boiler could mean a jump to 90% efficiency, and a heavier purse to boot.

Step two - consider the size of your home and your needs

The size of your home, especially the number of bathrooms/shower rooms you have, as well as how much heating and hot water your household uses, will largely determine your choice of boiler.

Woman with boiler

There are three main types of boiler: system, regular, and combination (or combi). Regular boilers have a cylinder (to store hot water) and often an expansion tank too. System boilers also use stored water, which allows them to feed several hot-water outlets, such as taps, at the same time.

Step three - how much space do you have? 

"Regular boilers require more space than combi or system boilers, as they often need an expansion tank in the loft, and are suitable for homes with more than two bathrooms and where hot-water usage is high but water pressure is low," says Martyn Bridges of boiler manufacturer Worcester, Bosch Group.

"System boilers have most of the major components of the heating and hot-water system built in, making them more efficient and less space consuming, as there is no need for a tank in the loft. They are connected to either a mains-pressure hot-water-storage cylinder or a more traditional low-pressure, tank-fed cylinder."

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Step four - could a combi work for you? 

Combis are a popular choice, but they're often not suitable for larger homes. With a combi, you only have to find room for the boiler itself - there's no hot-water cylinder or expansion tank, although some combis have built-in tanks, which can give the higher flow rates needed in bigger properties.

Combis heat water on demand, so you only pay for what you use, and deliver it at mains pressure. While combis are most suitable for homes with one bathroom/shower room, they can work well in homes with two, providing they're powerful enough. More than that and a system or regular boiler might be a better fit.

Step five - find a reputable engineer 

It's a good idea to ask a reputable heating engineer (find a Worcester-accredited one here) for advice about boilers, as more than one type may be suitable for your home. And remember to factor in future changes you may make, such as adding bathrooms/shower rooms, or expanding your household - the more people there are, the more hot water you'll be using.

Have you been putting off getting a new boiler fitted, due to the expense and upheaval? Or do you have any tips for making sure you get the right one? Let us know in the Comments below.