Which boiler is right for me?

Thursday 25th July, 2013 By Martin Fagan
Which boiler is right for me?

Choosing the right boiler can be complicated. As well as the costs involved, you have to consider the type that works best in your home.


By law, all new boilers must now be high-efficiency condensing boilers unless it is too difficult to fit one. Condensing boilers capture the heat that is normally lost by traditional boilers and reuses it. This means that a top of the range A-grade boiler could have as much as 96% efficiency.

The process can also be confusing because different types of boilers are sometimes known by different names. So here we've put together everything you need to know to make the right choice. Here are our top tips to finding the right boiler.

1. Combination boilers

Combination (Combi) boilers have become the best selling boiler type for gas central heating in the UK. They are small; fitting into cupboards, and very economical to run. And because they heat water directly from the mains, you don't have to wait for water to heat up - and your stream of hot water will be endless.

They are more economical than other types too. Because combi boilers don't use an external hot water tank, there is no cylinder to heat first, and no need to reheat the same water again if you've let it run cold.

However, for this same reason - the lack of a hot water storage tank - your nice hot shower will be interrupted if anyone else starts running the hot water in your home at the same time.

Is this the right boiler for me?

If you live in a small house or flat, without multiple bathrooms, or are short for space then a combination boiler will be an excellent choice for you.

If you currently have a cold-water tank in the loft but want to convert your loft space into an additional room, swapping your old boiler for a combination boiler will eliminate the need for the tank, and free up more space.

A combination boiler is the only way to have instant, on-demand hot water in your home without the inconvenience of having to wait for the water tank to be heated and you'll also get drinkable water from every tap.

2. Sealed system boilers (unvented)

A system boiler (also known as a closed or sealed system boiler) works on the principle of stored hot water. This means that you will need an airing cupboard or other space for the hot water storage tank.

Although a tank is needed in the airing cupboard, a system boiler still needs less space than a traditional open vent or heating only boiler, which utilises a second tank in the loft. Also, many of the individual components of the heating and hot water system are built in, which means that installation is quicker, neater, easier and more efficient.

With a system boiler you can run hot water from a range of outlets simultaneously, without someone else's shower running cold on them. You will also get good water pressure.

Is this the right boiler for me?

A system boiler is a great choice for a larger home or family with hot water needs that can't be met by a combi boiler, but who want to keep loft space free. You will need a tank in the airing cupboard though.

However, you'll have to wait for water to be heated when you want it, and it could run out if it's used too quickly.

Many people with older systems such as open vent boilers choose an unvented sealed system for their central heating and hot water. Although it is more expensive than simply replacing your boiler with the old system, you will be able to free up more space in your home.

3. Open vent and open vent sealed system boilers

An open vent boiler is the existing system in most people's homes. This type of system uses two water tanks, both located in the loft, and a hot water storage cylinder in the airing cupboard so it is very space hungry. One tank draws water from the mains supply and feeds the storage cylinder which, when heated by the boiler, can release hot water to taps all over the house.

The second tank is the feed and expansion tank which contains the correct level of water for your heating system, allowing for water expansion when you turn the heat on.

Showers, taps and running baths can be drawn in any room at the same time, but be aware that if the cylinder should run cold it will take a little time to reheat.

Many people switch from a traditional open vent boiler to an open vent sealed system boiler. This is a relatively cheap switch to make and will cut the need for one of the tanks in your loft.

Is this the right boiler for me?

Because it's the existing system in many people's homes, an open vented boiler is inexpensive to replace and making the switch to an open vent sealed system is also relatively cheap. However, both these systems use up loft space.

Like system boilers, open vent systems allow you to run hot water from a range of outlets simultaneously, without the water running cold elsewhere in your house. The water pressure is low though, and you'll only have drinkable water from one outlet, because it uses a storage system.

The hot water might also run out, and you'll have to wait for it to reheat.

4. Back boilers

Some homes still use back boilers, which are hidden behind a chimney, with a fire front to cover them. If you don't already have this system then it's not going to be a first choice for you as the water pressure is low, it is very space-hungry and you'll need somewhere to hide your boiler.

However, if you do already use a back boiler, then it might be the best option for you when the time comes to replace it.

Traditionally, back boilers are not very efficient, but great improvements have been made over the past 5-10 years, so by replacing your old back boiler, you could make huge savings on your annual heating bills.

Is this the right boiler for me?

Back boilers provide reliable heating and hot water, and allow you to draw hot water from more than one tap at the same time, without affecting other outlets. However, they need a lot of space - the boiler hidden behind your chimney, two tanks in the loft, and a cylinder in the airing cupboard.

Few people will consider a back boiler unless they already have that system in place as other, newer systems can easily handle the demands of a large home without taking up as much space. But if you already use a back boiler, you'll save a lot of money by sticking with the same system when the time comes to replace your boiler.

5. How much will it cost?

Installation costs can vary widely depending on the type of system you currently have and the type you would like to replace it with. You should expect to pay around £600- £800 for a good, gas boiler and more for an oil one, but it's the work itself that will also cost money. If you're having a full heating system overhaul, including radiators and heating controls, the cost will go up considerably.

If you will struggle to meet the costs you should first check to see if you're eligible for any grants or special offers.

If you can't get a grant or discount, most major installers offer a "buy now, pay later" scheme - some of these offer 0% interest for a set time, while others will tailor your repayments to suit your circumstances, but be wary of taking this type of finance - the interest is usually around 30% and you could get a much better rate on a loan from your bank.

6. Insure your new boiler

Once you have decided on a new boiler and got it installed, it's worth thinking about taking out some boiler insurance.

As it is a brand new boiler, you'd hope that it won't break down any time soon, however things can and do go wrong even with new things, so it is always best to be prepared.

Maintaining your boiler correctly is essential for a number of reasons, but the most important is to ensure it's safe and isn't posing a health risk.

To keep your boiler in peak condition it is important you get it checked at least once a year by a Gas Safety Registered engineer.

A lot of people do not bother taking out cover mainly because they don't like the idea of paying a monthly fee for something they may never need.

But, if you don't have cover it will cost you a small fortune to get your boiler fixed so a few pounds a month really is a small price to pay.

Depending on the exact type of cover it should also cover the cost of an annual service or if your boiler suddenly breaks down and needs an emergency repair.