Our central heating system is the most inefficient system I have ever seen so choosing what boiler we have is an important decision. Having all the ceilings down probably does not help, but now we are fitting a completely new boiler system, we want to ensure that it's efficient, reduces our fuel bill and has a negative impact on the environment. On top of that we also want to have a mega powerful shower and be able to ensure we can have hot water on tap, so when I am in the shower and Phil turns on the kitchen tap he does not hear me screaming from the floor above!

So what boiler do I need?

We have been considering fitting an unvented system - they are now installed in most new homes, but is this a good boiler option?

I was lucky enough to speak to Anthony who owns Lincs Gas. He has given us some easy to understand advice on what boiler to choose so I thought I'd share it with you!

Why replace my boiler?

"Replacing a boiler, which is over 15 years old with a new condensing model will save you over a third on your fuel bills and reduce the emissions collectively responsible for climate change. There is an extensive choice of boilers from which to choose and requirements are based on your specific needs."

Is my inefficient boiler costing me money?

"By replacing your boiler with a more efficient model you will not only save money but you'll be doing your bit for the environment too. If everyone in the UK fitted a new high efficiency boiler the amount of CO2 saved would fill almost 3.5 million hot air balloons!"

That would keep Richard Branson going.

What boiler?

Condensing combination boiler system

"The combination system is, by far, the simplest form of central heating system available.

"A combi boiler is two appliances in one - a pressurised central heating boiler and an instantaneous water heater.

"The main benefit of a combination boiler is that it heats water directly from the cold mains giving continuous hot water on demand to all taps at mains pressure with no need for any tanks. Water is only heated when required and is therefore usually more efficient and economical than a hot water storage cylinder which is part of a conventional system. However, hot water will normally only flow from one tap at a time and heat flow to radiators is interrupted whilst hot water is being drawn.

"Lincs Gas group recommends Worcester Bosch boilers - they are the best.

Condensing conventional boiler system

"With this type of system hot water cannot be provided on demand but must be stored, usually in a copper cylinder (normally located in an airing cupboard) and a cold water tank above it (usually in the attic) as well as a smaller central heating header tank (also usually in the attic).

As the water is pre-heated and stored, it can be used by more than one tap at a time without significant loss of flow. The conventional system is particularly suited to the larger property with more than one bathroom or where mains water pressure is too low for an instantaneous appliance such as a combination boiler.

Condensing system boiler

"Most types of boiler are also available as high efficiency or condensing boilers. There are high efficiency combination boilers, system boilers, or conventional boilers. The term condensing or high efficiency applies to the technology that is used to maximise boiler efficiency to use less fuel for more heat.

"A condensing boiler is a high efficiency modern boiler that incorporates either a larger heat exchanger or even a second heat exchanger. It produces lower flue gas temperatures, lower flue gas emissions, and reduced fuel consumption. It typically converts more than 88% of the fuel used into useful heat, compared to, typically, 78% for modern conventional types.

"By recovering and using heat that would otherwise be lost up the flue the best high efficiency boilers can operate with seasonal efficiencies in excess of 90%. Recovering the heat from the flue reduces the temperature of the flue gases to a point where water vapour produced during combustion is 'condensed out'. Thus the name high efficiency condensing boiler. A side effect is that this 'condensed out' water, known as condensate, which is usually acidic, has to be piped away to a drain or soak away.

"All condensing boilers will produce 'pluming' from the flue terminal which appears as steam. This pluming can drift into neighbouring property causing annoyance and possible condensation on window glass or frames so careful consideration should be given to placing of the flue terminal especially if it may affect neighbouring property.

"There is no cold water storage tank or central heating header tank. Water is heated in a special cylinder at mains pressure. Because water is pre-heated, it can be delivered to more than one tap at a time as with a conventional cylinder. However, as the system is at mains pressure, flow rates will normally be much improved (depending on local mains water pressure).

Pressured central heating and unvented stored hot water

"This system is particularly advantageous where there is a high demand for hot water such as properties with more than one bathroom or where improved shower performance is required without the use of a pump. Also advantageous where no head space is available for cold water storage tanks i.e. Loft conversions or flats.

"Some older systems can be upgraded using the existing boiler subject to building regulations. However, it is generally advantageous to use a purpose-designed pressurised system boiler which includes, within its case, all the components required for primary pressurisation.

"Systems are available giving pressurised stored hot water and conventional central heating (no cold water storage tank but retaining central heating header tank) or pressurised central heating and conventional stored hot water (retains cold water storage tank but no central heating header tank) or combinations thereof.

Thanks to Lincs Gas for all their advice. Now I know what boiler I need, as we have no loft space - I think we will opt for an unvented system. Let us know what YOU think!