At Fuller Heating, our experienced boiler installers in Kingston are regularly asked about the best heating systems for local homes. Combination (combi) boilers have become increasingly popular across the UK, but are they the right choice for your property? In this comprehensive guide, we’ll break down everything you need to know about combi boilers to help you make an informed decision.
What Is a Combi Boiler?
A combination boiler, commonly known as a combi boiler, is an all-in-one heating and hot water system. Unlike conventional boilers, combis don’t require separate water tanks or cylinders, as they heat water directly from the mains when you turn on a tap or shower.
The key features of combi boilers include:
- Space-saving design – no need for water tanks in the loft or airing cupboard
- Hot water on demand – no waiting for a cylinder to heat up
- Efficient operation – water is heated only when needed
- Mains pressure hot water – typically providing better shower pressure
- Simplified system – fewer components means fewer potential issues
These features have made combi boilers the UK’s most popular choice for new installations, particularly in small to medium-sized properties.
The Advantages of Choosing a Combi Boiler
1. Space Efficiency
Without the need for water storage tanks or cylinders, combi boilers are ideal for smaller properties where space is at a premium. This compact design means you can reclaim your airing cupboard for additional storage and eliminate bulky tanks from your loft space.
2. Energy Efficiency
Most modern combi boilers achieve A-rating energy efficiency, with some models operating at over 94% efficiency. Because they only heat water when required, they don’t waste energy maintaining a hot water cylinder, which can lead to significant savings on your energy bills.
As we’ve discussed in our article on understanding boiler efficiency ratings, this improved efficiency can translate to substantial cost savings over the boiler’s lifetime.
3. Hot Water on Demand
The ability to provide instant hot water without the need to wait for a cylinder to heat up is one of the most appreciated benefits of combi boilers. When you turn on a hot tap, the boiler fires up immediately to heat the water flowing through it, ensuring you’re never left without hot water (assuming your boiler is functioning correctly).
4. Lower Installation Costs
With fewer components and simpler pipework, combi boilers typically cost less to install than conventional systems. This makes them an attractive option for homeowners working with a limited budget.
5. Reduced Risk of Leaks and Frozen Pipes
Without water storage tanks in the loft, combi boilers eliminate the risk of tank leaks or frozen pipes in unheated roof spaces – a common problem with traditional systems during cold winter months.
When a Combi Boiler May Not Be Suitable
Despite their many advantages, combi boilers aren’t the perfect solution for every home. Here are some scenarios where alternative systems might be more appropriate:
1. Larger Properties with High Water Demand
If your household regularly uses multiple hot water outlets simultaneously (such as running several showers at once), a combi boiler may struggle to maintain adequate pressure and temperature. In these cases, a system boiler with a hot water cylinder might be more suitable.
2. Properties with Low Mains Water Pressure
Since combi boilers rely on mains water pressure, homes with poor incoming water pressure may not achieve satisfactory performance with a combi. Our engineers can test your water pressure during a survey to determine if a combi would be suitable for your property.
3. Homes with Multiple Bathrooms
Larger properties with multiple bathrooms often benefit from the stored hot water provided by system or regular boilers, which can handle simultaneous demand more effectively.
4. Properties with High Hot Water Usage
If your household consumes large volumes of hot water (for example, if you regularly fill a large bath), the instant heating capability of a combi might be less efficient than a well-insulated hot water cylinder.
Choosing the Right Combi Boiler Size
If you decide a combi boiler is right for your home, selecting the appropriate size is crucial for optimal performance. Boiler size refers to its power output, measured in kilowatts (kW), not its physical dimensions.
As a general guide:
- 24-27kW: Suitable for smaller properties with 1 bathroom
- 28-34kW: Appropriate for medium-sized homes with up to 2 bathrooms
- 35-42kW: Better for larger properties with higher hot water demands
Our detailed boiler size calculator guide can help you understand the specific requirements for your property type.
Popular Combi Boiler Brands and Models
At Fuller Heating, we install a range of high-quality combi boilers, including:
- Worcester Bosch Greenstar series
- Vaillant ecoTEC range
- Ideal Logic combi boilers
- Baxi combi models
As Worcester Bosch accredited installers, we particularly recommend their Greenstar range for its reliability, efficiency, and excellent warranty options.
Installation Considerations
Converting from a conventional boiler to a combi typically takes 1-2 days, depending on the complexity of the installation. During this process, our engineers will:
- Remove your existing boiler and hot water cylinder
- Install the new combi boiler in your chosen location
- Modify pipework as necessary
- Flush the system to remove any debris
- Install a magnetic filter to protect your new boiler
- Set up and test controls for optimal efficiency
For more details about what to expect during installation, read our article on how long it takes to install a boiler.
Making Your Decision
When deciding whether a combi boiler is right for your home, consider:
- Your property size and number of bathrooms
- Typical hot water usage patterns
- Available space for the boiler and related equipment
- Your budget for installation and running costs
- Local water pressure conditions
Our experienced heating engineers are always available to provide personalised advice based on your specific circumstances and requirements.
Need Expert Advice on Combi Boiler Installation?
If you’re considering a combi boiler for your home, our Kingston heating specialists can provide a free, no-obligation assessment and quotation. We’ll help you determine if a combi boiler is the right choice for your property and recommend the most suitable models based on your home’s specific requirements and your budget.
Contact Fuller Heating today to arrange your consultation and take the first step towards efficient, reliable heating and hot water for your home.
