WHAT YOU NEED TO KNOW?
When you need a new gas boiler there are lots of things to consider. It is essential to talk through your options and clarify your needs with the person who'll be installing your new boiler.
Combi vs heat-only
Your main decision when buying a new boiler is whether to buy a combination (Combi) or a heat-only one (System or Open Vent). Ask your chosen installer which type is best for your home, and why. For more information about this, see our Combi, System or OpenVent section.
A competent Installer
Whoever you choose to install your boiler, make an appointment for them to come and discuss your heating and hot water needs. Boilers come in many different sizes and you should work with the installer to get the boiler that best matches your current needs and future requirements.
Your boiler should be installed by what is known as a 'competent person'; someone who is able to install it so that it complies with building regulations, and can certify that it does so. The current accreditation scheme is Gas Safe Register (this replaces Corgi). Always ask to see the Installers Gas Safe Register ID card to be assured that he is able to carry out the work in a safe, professional way.
Heating output
Boilers are available in a range of heating outputs, typically from 12 to 40kW, which are suitable for different households. This energy value is based on the maximum energy the boiler can convert to heat your water. The smaller your home, the fewer kW you need. Typically a 24kW will be sufficient for a small house or flat, a 30 kW is for the average home and a 38kW for a home with a larger family. However, each home has different needs and it's best to consult your installer as the size of boiler depends on a number of factors.
- How many radiators you have
- How many bathrooms (Baths and showers will both put a strain on your boiler).
- Whether you have double glazing
- What kind of demands will be placed on the hot water system
- The age of your home
- Your home's insulation (use loft insulation to stop heat escaping
- Whether you have high ceilings
The Sedbuk website has a handy interactive calculator that you can use to help determine your requirements. It asks you questions about the size and age of your home, how many rooms it has, plus whether it's insulated. It then produces a recommendation based on your answers.
Discuss your current and future needs
Installing a new boiler is also a good time to review your entire heating needs. Key things to discuss are:
- Energy efficiency improvements you've made since the last boiler was fitted, or changes you're planning to make in future. Measures such as double glazing, loft insulation, cavity wall insulation or draught proofing will reduce the heat loss from your home and reduce your heating requirements.
- What central heating controls will make your system operate most effectively?
- Changes you plan to make such as adding more rooms or changing a bedroom to a bathroom.
- How well your current system meets your requirements. Could any rooms do with an extra or larger radiator, for example, or could you free up space by changing to a combi boiler?
Questions to ask
You should ask your installer several more questions, so you know what to expect from your new boiler:
- How will a new condensing boiler be different from your current boiler?
- How did they choose the size and make of the boiler?
- Will they receive any commission from the sale of the boiler?
- Is there a warranty and what will it cover? (Dimplex has a 5 Year warranty)
- How often should it be serviced?
- How will they make sure the plume is not a nuisance?
Once you've assessed your needs, your installer will recommend a new boiler and may even provide an outline of the savings you can expect to make with a more efficient model.
Other things to consider
Condensate drain - Condensing boilers produce an acidic liquid from the condensing process, which must be drained away from the appliance. This may affect where it can be sited, as it'll need to be plumbed into a drain.
Plume - Condensing boilers produce a plume of water vapour when the boiler is operating. The flue must be sited carefully, in accordance with building regulations, to avoid the plume being a nuisance, for instance about the roof line.
Wall mounting - All the boilers that we have tested are mounted on a wall, but don't assume they can all be shut in a kitchen cupboard. If you specifically want to hide the boiler, discuss this with your installer.
Servicing - All the manufacturers recommend getting an annual service carried out on your boiler to ensure it is operating efficiently and safely. Failure to have your boiler serviced annually may result in voiding your warranty.