June 18, 2023


Everything You Need to Know about Boiler Installations in the UK

Boilers play a crucial role in providing heating and hot water to homes across the United Kingdom. With the country’s chilly climate, a reliable and efficient boiler is essential for comfort and well-being, particularly during the colder months.

The purpose of this article is to provide a comprehensive guide to boiler installations in the UK. We will cover everything from understanding different types of boilers and factors to consider when choosing a new boiler, to the installation process, legal requirements, financing options, maintenance, and choosing a reliable experienced installer.

Understanding Boilers

Definition and function of a boiler

A boiler is a heating appliance serving an essential and important purpose in your home. Boilers are designed to produce heat and hot water supply to your taps.  They burn either oil or natural gas to produce heat, which is then transferred to water. The heated water then circulates through your heating pipes connected to each of your radiators or underfloor heating to provide warmth and hot water throughout the home to your taps.

Types of boilers commonly installed in the UK

Conventional boilers:

Also known as regular, traditional or heat only boilers.

Can work on its own only providing heating and no hot water to taps.

Works with either a vented or unvented hot water cylinders.
Vented hot water cylinders require a cold-water storage tank and feed and expansion tank.

Unvented hot water cylinders run on mains water and do not require a cold storage tank.

Suitable for homes with high hot water demand and multiple bathrooms.

Combi boilers:

Combination boilers are designed to provide heating and instant hot water

No need for a separate hot water cylinder or cold storage tank.

Combi boilers are connected to cold water mains, heating water instantly on demand.

Ideal for small to medium-sized homes wanting instant and unlimited hot water.

System boilers:

Similar to conventional boilers but has central heating pump and expansion vessel built into the boiler.

Compatible with both vented and unvented hot water cylinders.

Do not require a header tank which conventional boilers require when using a vented cylinder.

Do not require a cold storage tank when using an unvented pressurised hot water cylinder.

Homeowners should think twice about switching from a conventional boiler to a system boiler as the latter will expose your central heating pipework and radiators to greater pressure which can shock your system and cause leaks.

Suitable for homes with high hot water demand and limited loft space.

Factors to consider when choosing a boiler

Size and capacity:

Consider the size of your property and the number of bathrooms to determine the appropriate boiler size and capacity.

Check your available water pressure

When you have a survey carried out by a boiler installer it is vital you ask them to measure your flow rate and pressure to understand how many litres of water per minute is available on your incoming mains water pipe. 

Depending on your available water pressure you will gain a better understanding of your suitable options of boiler and setup. At The Boiler Installation Specialists we always ensure we check customers flow rate 1. to ensure the chosen product will be performing as per its purpose 2. to ensure customers do not overspend on a setup which is unable to carry out its designed performance.

Energy efficiency ratings:

Look for boilers with high energy efficiency ratings (such as ErP ratings) to reduce energy consumption and lower utility bills.

Future plans

If you are thinking about extending your property it is important this is factored in as there will be additional radiators and bathrooms to provide heating and hot water to. Failing to take this into account can end up being very expensive as running additional demand can shorten the life of your boiler which then has to work extra hard to keep up with the total demand.

Fuel types:

Gas and oil boilers are the most common and cost-effective option in the UK. We do not install biomass, warm air or electric boilers. This is because, electric boilers runs purely on electric which is very expensive on its own and using electricity to heat your hot water and heating radiators end up with customers limiting turning their heating on as they are extremely conscious of the running costs.

Renewable energy options like ground source heat pump and air source heat pumps are not suitable for the majority of existing homes in the UK. They can provide a solution to brand new homes which have been specifically designed to be heated by these means but these homes are pretty much built and constructed in such a way that they can be heated by a light bulb.

They run at a much lower temperature which means that your existing heating system will provide nearly half the heat output temperature compared to oil or gas boilers. Having a air or ground source heat pump installed is not only a matter of having the unit installed, in many cases there are additional steps the homeowners need to take in order for it to do its job like addition of triple glazing, underfloor heating, larger radiators and insulation. In our experience we are removing these solutions where customers feel like they have been mislead and opt to go back to either to a natural gas boiler system or oil boiler system.

Cost considerations:

Take into account the upfront cost of the boiler, installation expenses, and potential long-term savings on energy bills.

Endless amounts of repairs backed by no guarantee can leave you out of pocket. 

Our view is, once a boiler is in its older days it becomes much more fragile, once you start working on it to repair one issue it triggers other things to go wrong with it.

Boiler Installation Process

Hiring a qualified engineer

When it comes to boiler installations, it’s crucial to hire a qualified and Gas Safe or OFTEC registered engineer. They possess the necessary expertise to install boilers safely and in compliance with regulations. They are also able to provide you with a commissioning certificate on completion as proof that they have left your home safe. 

Qualified OFTEC and GAS SAFE engineers will on completion of works issue you with a building control certificate which is important as it is required by law to prove the work was carried out by a competent individual. Without a building control certificate you will encounter problems when you come to sell your property and might have to pay again for the work to be completed by a competent person.

Initial assessment and survey

The Boiler Installation Specialists will arrange for our qualified OFTEC/GAS SAFE engineer to conduct an initial assessment of your property to understand your heating requirements. They will perform a survey to evaluate the existing heating system, identify any necessary upgrades, and determine the most suitable boiler type and size for your needs. We will also carry out a flow rate test on your incoming water mains.

Determining the appropriate boiler type and size

Our lead engineer will have a conversation with yourself to understand your needs and lifestyle. We will also ask you about any future renovations and extensions so we can incorporate this when sizing your required boiler. Based on the assessment and survey our engineer will recommend the most appropriate boiler type and size that meets your heating and hot water demands efficiently.

Upgrading or replacing existing systems

If you have an existing boiler, our engineer will check your existing central heating setup where we check if your existing heating pipework type is suitable with the chosen boiler type. 

If you have a  stored hot water cylinder which will run with the new A-rated energy efficient boiler we will check if you have the correct setup to prevent any adverse effect on the new modern boiler performance. If we find you have an old gravity setup which means you have very little control over your hot water and heating this will require upgrading to a fully pumped system which will entail us adding electrical components to enhance the system’s efficiency. At the end of this installation you will be able to control your heating and hot water independently.

On installation day

Before the installation, our engineer will prepare the site, ensuring proper ventilation and clearances for the new boiler. We will also protect the areas where we will be working and explain at all times to our customers what will be happening during the installation as well as answering any questions.

Installation timeline and considerations

The duration of the installation process varies depending on factors such as the complexity of the project and the type of boiler being installed. The engineer will provide an estimated timeline and discuss any temporary disruptions to your heating and hot water supply during the installation.

Safety precautions during installation

Safety is paramount during boiler installations. Our engineers will follow strict safety procedures, such as isolating the power and fuel supply, using appropriate tools and equipment, and ensuring proper ventilation and flue installation.

Testing and commissioning

After the installation, our engineer will commission and test the boiler and its components to ensure proper safe functioning and that the commissioning is in line with both gas safe regulations and manufacturers requirements. We will advise you how to use your new heating controls and if needed we will adjusting settings and controls for optimal performance.

Legal Requirements and Regulations

Gas Safe and OFTEC Regulations 

Only gas safe registered engineers can carry out gas work. You can check if an engineer is gas safe registered by searching for them on the gas safe register here ( https://www.gassaferegister.co.uk/find-an-engineer-or-check-the-register/?gclid=CjwKCAjwkLCkBhA9EiwAka9QRvAnYrpZywbDgHvWlwse13NSZUHytBXtcmSy_YBpQEgZ9MloiAbE7xoCSZsQAvD_BwE) Gas boiler installations must comply with the Gas Safety (Installation and Use) Regulations. 

You should only use an OFTEC-qualified engineer to work on your oil boiler system or oil tank. This is to ensure they are fully aware of all regulations and leave you with a safe installation. OFTEC engineers will also be able to commission your installation and issue you with a building control certificate. Check if an engineer is OFTEC qualified here https://www.oftec.org/find-technician

Both Gas Safe and Oftec regulations outline the legal responsibilities of the installer, homeowners, and landlords, emphasising the importance of regular maintenance and annual safety checks by a registered engineer.

Building Regulations

Boiler installations in the UK must comply with relevant building regulations. These regulations cover aspects such as ventilation, flue systems, energy efficiency, and controls. If you have a new oil or gas boiler installation carried out it is vital your installer issue you building control certificate as this means the work has been carried out by a competent person as per regulatory requirements.

Energy Efficiency Standards

Boilers must meet certain energy efficiency standards to minimise carbon emissions and promote sustainable heating. This is why you should never buy a second hand boiler and choose a boiler which is available on the current market.

Certifications and qualifications for engineers

Ensure the engineer you hire is Gas Safe registered, which is a legal requirement for anyone carrying out gas-related work. 

Engineers working on oil boilers, oil tanks and oil heatings systems should be qualified by OFTEC. This means that they have received all trainings to carry out the works and comply with building regulations.

Cost and Financing Options

Factors influencing installation costs

Several factors influence the cost of boiler installations, including the type and size of the boiler, complexity of the installation, any necessary upgrades to the heating system, and regional variations in labor costs.

Financing options

To help homeowners manage the cost of boiler installations we are pleased to announce we offer several different finance options. These include 0% finance and buy now pay later optionsenabling you to have the work done sooner rather than later without breaking the bank.

Return on investment and long-term savings

While boiler installations involve upfront costs, investing in an efficient boiler can lead to significant long-term savings on energy bills. Modern boilers are designed to maximise energy efficiency, reducing fuel consumption and lowering heating costs over time. The Boiler Installation Specialists are approved agents for Grant boilers, Worcester Bosch and Vaillant boilers which means you have complete peace of mind as you will receive a 10 years parts and labour guarantee to cover future repairs of your new boiler.

Maintenance and Servicing

Importance of regular maintenance

Regular maintenance is crucial for keeping your boiler in optimal condition. It helps prevent breakdowns, extends the lifespan of the boiler, maintains energy efficiency, and ensures the safety of your home.

Recommended servicing intervals

It is recommended to have your boiler serviced annually by a qualified engineer. Regular servicing helps identify and address potential issues before they escalate, ensuring the boiler operates efficiently and safely.

DIY maintenance tips

While professional servicing is essential, there are some DIY maintenance tasks you can perform, such as checking pressure levels and bleeding radiators. Homeowners should not work on their boilers.

Choosing a Reliable Installer

Researching reputable companies

Research local boiler installation companies and check their reputation. Look for established companies with a track record of delivering high-quality installations and excellent customer service. Here at The Boiler Installation Specialists we have successfully been running since 2007 but we have over 30 years of experience on offer. Our reputation says it all, endorsed by Which? trusted traders and trading standards means you are in safe hands.

Checking qualifications and accreditation

Ensure that the installers you consider are Gas Safe and OFTEC registered and hold the necessary qualifications and accreditations. This guarantees their competence and adherence to safety standards. 

Reading customer reviews and testimonials

Read reviews and testimonials from previous customers to gauge the satisfaction levels and experiences of others who have used the installer’s services. The Boiler Installation has hundreds of reviews by many satisfied customers raving about the service they received from us. We also recommend you research the company to establish how long they have been trading and consistency in their services.

Obtaining multiple quotes and comparing

Obtain quotes from multiple installers to compare prices, services offered, warranties, and guarantees. This allows you to make an informed decision based on both quality and affordability. When you compare quotes it is important you check weather the product/model that has been quoted is the same. It is also important to understand what work the installer mainly do as many heating engineers do various types of jobs which are different from installation work. This means that when you choose The Boiler Installation Specialists to install your new boiler or heating system, you will be dealing with a firm who carries out installation work on a daily basis which will give you excellent quality and service.

Asking for warranties and guarantees

Ask installers about warranties and guarantees provided for the boiler and their workmanship. A reputable installer will offer warranties to provide peace of mind and assurance of their commitment to quality. Long guarantees are offered by installers like The Boiler Installation Specialists as we have been hand selected by major manufacturers likes of Worcester Bosch, Vaillant and Grant boilers. They trust us to carry out exceptional work and back our business offering customers market leading manufacturers guarantees.


Boilers are essential for heating and hot water supply in the UK. Understanding different types of boilers, considering factors such as size, energy efficiency, and cost, and following legal requirements are crucial when choosing and installing a boiler.

Professional installation ensures safety and optimal performance, while regular maintenance by qualified engineers keeps the boiler efficient, reliable, and safe.

By following the guidance in this article, homeowners in the UK can make informed decisions, choose reliable installers, and take proactive steps to ensure a smooth and successful boiler installation, leading to long-term comfort and energy savings.

If you would like to contact us for your free-of-charge installation quote please call us on freephone 0345-2624989.

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