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Time to replace your boiler?


Time to replace your boiler?

There is nothing better than a warm, welcoming home at this time of year and it’s easy to forget how much we rely on our boilers to do that for us.  As the cost of running your boiler is likely to account for up to half your household energy bills, perhaps it’s time to consider whether yours is still efficient or whether it needs replacing.

The energy efficiency of boilers has improved dramatically over recent years and investing in a new model should make a big difference to your carbon footprint as well as your outgoings.

Signs that your boiler might need replacing

  • if it is more than 15 years old. All boilers have a life span and the chances are that if yours is this old it won’t work as efficiently as the newer models. Any repairs could be costly too due to parts being difficult to find
  • if you have had to call out a boiler repair engineer more than once a year - are the combined repair costs outweighing the cost of a new boiler?
  • if you’ve noticed your energy bills creeping up.  Check your boiler’s energy efficiency rating. Modern A-rated boilers should be 90% efficient but older G-rated models run at 70% or less. Upgrading from an A to a G-rated boiler could save you up to £200 a year and will be better for the environment
  • your boiler leaks water - this could be a sign that a valve or seal has broken and can lead to further problems such as electrical damage or even structural damage if left unchecked
  • your boiler or radiators are noisy. It could be completely harmless but vibrating or tapping could be a sign of a fault which a gas engineer needs to look at
  • your boiler’s blue flame has turned yellow/orange. If this happens you should call an engineer immediately as it can be a sign of a serious problem involving the carbon monoxide in your system.

Do I need planning permission?

You don’t usually need planning permission to install a boiler if the work is all internal. Though different rules apply if you live in a listed building or conservation area, so check with your local planning department.

If your installation needs an outside flue this is also normally classed as permitted development but there are exceptions.  See the chapter in our Homeowner Renovation Guide here.

Who can carry out the work for me?

You do not need to submit a building regulations application for this type of work to building control.  Depending on the type of new boiler you choose, the installer will need to be registered under one of the a relevant Competent Person Schemes and will be able to self-certify the work. 

They must follow the guidelines set out in Approved Document J and each boiler must have a minimum efficiency of 86% for gas and 85% for oil. The Competent Person installer will give you a completion certificate and building control will then receive electronic notification that the work has been completed. (This is then recorded against your property history so that should you come to sell or remortgage your property in the future there is information to say the work was carried out in compliance with the building regulations.)

You can find a list of the different Competent Person Schemes, including types of boiler installation in our Homeowner Renovation Guide here. To search for a Competent Person in your area you can use the search facility here.

Types of boilers

The best location for boilers is within garages, kitchens or utility areas.  There are several types of boilers available on the market, all offering different benefits.  These include:

  • Condensing boilers
  • Oil fired boilers
  • CHP boilers
  • Biomass boilers

Read more about the pros and cons of each in our Guide here


When you have decided which type of boiler to buy you will need to organise installation with a Competent Person (qualified engineer).  If you are having the same type of boiler this can often be replaced within the same day. If it is an older system or a completely new one this will take longer.

It is very important that once your new boiler has been installed that your engineer provides you with a Building Regulations compliance certificate and that you keep if safe for future reference. You should also confirm that they will be sending notification to their Governing Body so that the Local Authority buidling contol team also receives notification that the work has taken place.


There are specific rules related to the positioning of flues partly to ensure safe discharge of boiling water if a fault develops.

Looking after the environment

Most boilers are fossil fuel powered, which the government is trying to encourage people away from. You could therefore consider low carbon alternatives. However, they require more planning with regard to installation and are typically a lot more expensive than a standard boiler replacement. But, they do contribute to the country’s drive toward net zero.

For further information and advice, Surrey residents can contact Action Surrey who provide free advice and guidance on these matters.They also have a government grant scheme in place which can help reduce the costs of installing home energy efficiency measures and low/zero carbon heating technologies for eligible residents. If low carbon tech is still unworkable for you at the moment and you have an old inefficient boiler, replacing it with a new more efficient one will save you money and be an important step in lowering your carbon emissions.

Think about an annual boiler service

It is good advice to get your boiler serviced regularly. A service engineer will check your boiler is safe, as well as help to maximise its performance and its reliability. Think of it like an MOT to prevent any unwanted breakdowns or costly surprises next winter!

Can we help with your next project?

If you are considering replacing your boiler as part of wider home improvement plans take a look at the other chapters in our Homeowner Renovation Guide or our further Guide to Extending your Home Both are full of helpful tips and hints on projects from replacing your bathroom or kitchen to extensions and conversions and creating open plan living spaces.


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