Electric Boiler Installation Guide to Fitting & Different Types

Installing an electric boiler is a big decision that requires proper planning and an understanding of the process. 

To make the process as straightforward and stress-free as possible, we’ll guide you through each step of an electric boiler installation and cover everything from selecting the right size to engaging qualified professionals, boiler costs, maintenance, and more. Let’s start with the basics.

How Does an Electric Boiler Work

Electric boilers use electricity to heat water, which then circulates through your home’s radiators or underfloor heating system. Inside the boiler, there’s an element (like a big kettle) that heats the water. When you turn on your heating, cold water flows in, gets heated up, and then pumps out to warm your home. 

It’s a simple process, but it’s effective for keeping your place warm and cosy.

Can I power an electric boiler from a ring main?

Generally, it’s not recommended to power an electric boiler from a ring main. Electric boilers typically require a lot of power, often more than a standard ring main can safely provide. Using a ring main for your boiler could overload the circuit, potentially causing electrical issues or even safety hazards. 

What is a dedicated circuit?

A dedicated circuit is an electrical circuit that’s designed to power a single appliance or device. In the case of an electric boiler, this means a circuit that runs directly from your main electrical panel to the boiler without any other outlets or devices connected to it.

Do electric boilers need their own electrical supply circuit?

Yes, electric boilers usually need their own dedicated electrical supply circuit. This is because they draw a significant amount of power, often more than most household appliances. Having a separate circuit ensures that your boiler has a stable, reliable power supply without interfering with other electrical devices in your home. It also helps prevent overloading, which could trip your circuit breakers or, worse, create a fire hazard.

Does it matter what cable I use?

Yes, the type of cable you use for your electric boiler matters a lot because using the wrong cable could lead to overheating, power loss, or even electrical fires. The cable needs to be able to handle the high current that electric boilers draw. Typically, you’ll need a thick, high-capacity cable, often 10mm² or even larger, depending on the boiler’s power requirements. 

Electric boiler running costs

The running costs of an electric boiler can vary quite a bit. They depend on factors like your electricity tariff, how often you use your heating, and how well-insulated your home is. 

Generally, electric boilers are more expensive to run than gas boilers because electricity costs more than gas per unit of energy. However, they’re often more efficient, which can offset some of the cost. The average annual running cost for an electric boiler in the UK is approximately £1,717 for a typical 3-bedroom house.

How to Choose the Right Electric Boiler For Your Home

Selecting the right electric boiler involves considering several factors.

Size of your home or business

The size of your property plays a crucial role in choosing an electric boiler:

• Small apartments or homes (1 bathroom): A boiler with an output between 4-11 kW should be enough.
• Medium-sized homes (2-3 bathrooms): Look for boilers between 11-20 kW.
• Large homes (3+ bathrooms): You might need 20-35 kW or more.
• Small businesses: Depending on usage, they might require 20-30 kW.
• Larger commercial spaces: May need 40 kW or more.

These are just general guidelines. Your specific needs might vary based on insulation, number of radiators, and hot water usage.

Assessing your heating and hot water requirements

A good rule of thumb is to allocate 1.5 kW of boiler output per radiator. If you need hot water, too, add an extra 3 kW. For example, a home with 6 radiators would require about 12 kW (6 x 1.5 kW + 3 kW).

Types of Electric Boilers

• Electric combi boilers: These do not require hot water storage cylinders and provide hot water on demand. They are popular in flats and small to medium-sized homes where space is scarce.
• Heat-only boilers: These require a separate hot water storage cylinder and are suitable for larger homes with multiple bathrooms.
• System boilers: They also require a separate hot water storage cylinder, but they have built-in components, making installation easier and more efficient.

Key features to look for

• Energy efficiency rating: Look for “A” rated boilers for the best efficiency.
• Smart controls: Some boilers offer app control for easy management.
• Quiet operation: Important if the boiler will be near living spaces.
• Compact size: Crucial if you’re short on space.
• Warranty length: Longer warranties can save you money in the long run.

Price Considerations

Electric boilers can range from £500 to £4,500, not including installation. Here’s a rough breakdown:

• Budget models: £700 – £1,500
• Mid-range models: £1,500 – £2,500
• High-end models: £2,500 – £4,500
• Installation costs typically range from £500 to £1,500, depending on the complexity of the job.

Electricity supply

Most homes have a single-phase 230V supply, suitable for boilers up to 12 kW. Larger boilers (18-30 kW or more) need a 400V three-phase supply, which might require an upgrade to your electrical system.

Professional assessment

While these guidelines are helpful, it’s always best to get a professional assessment. A heating engineer can give you expert advice tailored to your specific situation so you can choose the most suitable and cost-effective option for your home or business.

Preparing for Electric Boiler Installation

Once you’ve determined the right electric boiler for your home, it’s time to prepare for the installation process. This involves:

• Hiring qualified professionals
• Obtaining necessary permits
• Preparing the installation site to ensure a smooth and compliant electric boiler installation

Hiring qualified professionals

Installing an electric boiler isn’t a DIY job. You’ll need to hire skilled electrical or heating engineers who can handle both plumbing and electrical work, especially if you’re switching from gas to electric heating.

Apart from the installation, heating engineers are also responsible for ensuring that the electric boiler complies with building regulations, which includes verifying the presence of a third-party electrical assessment label on the boiler.

Hence, it’s recommended that you hire a company that provides certified electricians, plumbers, and Gas Safe engineers for a complete and compliant electric boiler installation service.

Obtaining necessary permits

Before starting the installation process, it’s critical to acquire any necessary permits or approvals.

Electric boiler installations must adhere to relevant building regulations and safety standards. A reputable installation service will ensure that your electric boiler installation is fully compliant with these regulations.

It’s also important to manage the proper disposal of the old boiler in accordance with local council regulations for safety and compliance.

Preparing the Installation Site

Before the electric boiler installation, a professional should check your home’s electrical infrastructure to ensure it can handle the high power usage of an electric boiler. This includes:

• Checking the condition of the wiring, especially in older buildings
• Ensuring the installation site has a dedicated electrical supply circuit with a correctly sized circuit breaker
• Making sure the electric boiler is not supplied from a ring main

Implementation of a dedicated breaker at the distribution board, connected with the correct size and type of electrical cable, is essential for safe operation.

It’s also important to install an isolation switch near the electric boiler for safe maintenance and emergency situations.

The space-saving design of electric boilers allows for flexible installation locations, often reducing installation complexity and costs.

The Electric Boiler Installation Process

With the groundwork laid, we can now proceed to the actual installation process. This involves:

1. Safely disconnecting and removing the existing gas or oil boiler
2. Installing the new electric boiler
3. Performing necessary tests to ensure the boiler operates efficiently and safely

Removing the old boiler

The first step in the installation process is to safely disconnect and remove the existing gas or oil boiler. The removal of a gas boiler includes the safe capping off of the gas line by a certified heating engineer.

When an oil boiler system is removed, the oil feed and the old oil tank must also be removed and safely disposed of.

The process of boiler removal also involves taking out the flue, which vents combustion gases, as well as the condensation pipe from condensing boilers. Any residual openings left by these components need to be properly sealed for safety.

Installing the new electric boiler

Once the old boiler is safely removed, it’s time to install the new electric boiler. The boiler is secured in place, ensuring it is correctly levelled and in the appropriate location for the power supply and plumbing connections.

Plumbing connections for electric boilers typically involve a simple cold input and hot output for system boilers, with additional connections for domestic hot water in combi boilers.

To control your new electric boiler, you’ll need room thermostats connected to a control circuit. For instance, ThermoSphere boilers require a wired connection to a °C terminal for heat call and a 3 Amp supply for controls.

Lastly, a system cleanse is performed to remove debris like black magnetite from the system, followed by the addition of a corrosion inhibitor to protect against rust and hydrogen gas formation, thereby ensuring long-term efficiency.

Testing and commissioning

Following the installation, a series of checks, tests, and adjustments are performed to ensure efficient and safe operation of the boiler. This process, known as boiler commissioning, ensures that the new electric boiler meets performance and safety criteria.

How Much Does an Electric Boiler Cost to Install?

The cost of installing an electric boiler can range from £650 to £2,500. This range accounts for different factors, such as the complexity of the installation and the need to move the boiler, but not all installations will be at the higher end.

Maximising Efficiency and Reducing Running Costs

With the electric boiler installed and operational, you’ll want to maximise its efficiency and reduce electric boiler running costs. Here’s how you can do that.

Energy-efficient settings and controls

One way to enhance the efficiency of your electric boiler is by setting a room thermostat to the lowest comfortable temperature, typically between 18 and 21 degrees Celsius.

This can save energy without compromising comfort. Programmable room thermostats allow different temperatures to be set for different times of the day, enabling users to heat their homes more efficiently.

Thermostatic radiator valves (TRVs) enable individual room temperature control, and boiler interlocks can save energy by only operating the boiler when heating is needed.

Moreover, smart electric boiler controls can help you monitor energy consumption, optimise boiler performance, and catch potential issues for proactive maintenance.

Integrating Renewable Energy Sources

In addition to smart controls and efficient settings, integrating renewable energy sources like solar panels can result in significant reductions in energy use and costs. Some benefits of solar thermal systems include:

• Direct heat capture from the sun
• On-demand hot water with storage tanks
• Decreased electric boiler operation
• Lower running costs
• Enhanced energy independence

The use of solar batteries and hybrid solar thermal systems ensures that renewable energy is available even during periods with less sunlight, optimising heating systems to be more renewable-centric and less reliant on the electric boiler.

As the push for sustainable energy intensifies, electric boilers can be effectively integrated with renewable resources, such as solar and wind power, using the appropriate inverters.

Maintenance and Troubleshooting

While electric boilers offer a safer installation option due to the absence of a flue and no risk of harmful gas leaks, they still require regular care and maintenance to ensure optimal performance. Here’s how to maintain and troubleshoot your electric boiler.

Annual servicing

Even though it’s not legally required, an annual boiler service is key to keeping your electric boiler in top condition and ensuring efficient performance.

During the annual service visit, the professional will:

• Check safety valves, components, and wiring to identify issues such as discolouration caused by improper connections or incorrect cable sizing
• Test the system’s performance
• Examine specific parts such as electrical connections and the heating element for proper function

Regular maintenance is important to ensure the safe and efficient operation of the system – see the cost of an electric boiler service here.

Common electric boiler issues and solutions

Despite their high efficiency and safety, electric boilers can sometimes encounter issues. One common problem is the boiler failing to turn on, which could be due to power supply problems and is often indicated by error messages or the absence of the power light.

Another common issue is low water pressure, which stops the boiler from operating and typically requires re-pressuring the system after checking for leaks.

RCD tripping may signal an overloaded circuit or an earth leak, requiring verification of the circuit load and checking for leaks.

And if the electric boiler is functioning but fails to produce heat, this could be due to an issue with the heating elements, which can be diagnosed through current or resistance checks.

Regularly activating the electric heating system for short periods, even in warmer months, can help prevent the boiler components from seizing and reduce the risk of breakdowns.

The Future of Electric Heating Systems

Looking ahead, electric heating systems such as air source heat pumps, flexible grid systems, and demand-side response technologies are expected to support the widespread use of electric heating in both residential and commercial sectors.

Electrically heated buildings have a greater potential to participate in demand-side response schemes, which not only allows them to manage energy consumption more effectively but also offers the opportunity for financial incentives.

The UK government’s Review of Electricity Market Arrangements (REMA) presents a strategic effort to improve energy security and reduce the cost of electricity.

This initiative is likely to facilitate the broader adoption of electric heating solutions, making electric combi boilers a more sustainable option for the future.

Ready to upgrade your heating? Get a free quote from Boiler Central today.

Summary

We’ve explored the ins and outs of electric boilers, from determining the right one for your home to understanding the installation process, maintenance, and troubleshooting.

Their high energy efficiency, zero on-site carbon emissions, compatibility with renewable energy sources, and suitability for a wide range of properties make them a promising solution for modern heating needs.

While electric boilers currently have higher running costs than gas boilers, advancements in technology, government initiatives, and a growing focus on sustainable energy sources are likely to make them a more cost-effective and eco-friendly option in the future.

It’s clear that electric boilers are not just a temporary trend, but a key player in the transition towards a sustainable, energy-efficient future.