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Last updated: 29th August, 2023


Best Boilers for Big Families

Best Boilers for Big Families

Key takeaways

  • A comprehensive understanding of boiler types will ease the decision-making process for finding the ideal one for large households.
  • Evaluating boiler brands, efficiency, sizing, and output enables selection of a well-suited appliance for your large family home.
  • Prioritising safety considerations, hot water, and heating controls ensures a reliable and efficient heating system in your home.

iHeat's guide to the best boilers for big families and larger properties. We explain the different types of popular boiler - combi, system and heat only and their benefits for big properties.

Selecting the ideal boiler for large families can be daunting with many important factors to consider.

Large households require a boiler that can effectively satisfy their heating and hot water demands while maintaining energy efficiency. 

This article will delve into various aspects of boilers to help you choose the perfect appliance for your big family home.

Understanding the different types of boilers on the market is the first step towards making the right choice.

Combi, system, and conventional boilers have unique benefits and drawbacks. 

We will discuss the best boiler brands for large houses, considering their efficiency, sizing, output, installation, and maintenance requirements.

We will also cover crucial safety considerations and hot water and heating controls to ensure that you select a boiler that is not only powerful but also safe and reliable.

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Understanding Boiler Types

When selecting the perfect boiler for a large family, it's essential to understand the different types available.

This section will discuss three main types of boilers: Combi Boilers, System Boilers, and Heat-Only Boilers. Each type has pros and cons, and the best choice depends on your household's needs.

Combi Boilers

Combi boilers, or combination boilers, are a popular choice for many households as they provide both central heating and hot water from a single unit.

These boilers heat water directly from the mains, which means that there's no need for a separate hot water storage cylinder or cold water tank. This makes them compact and relatively easy to install.

However, combi boilers may not always be suitable for larger homes with multiple bathrooms.

They may struggle to provide hot water across numerous taps simultaneously, especially when multiple family members need hot water at the same time. Additionally, combi boilers are typically more effective in smaller homes with less demand for hot water.


System Boilers

System boilers are designed to work well in medium or large homes that have multiple bathrooms. These boilers require a separate hot water storage cylinder but don't need a cold water tank as they draw water directly from the mains.

A key advantage of system boilers is that they can provide hot water to multiple taps at once. If you have a home with 3 bedrooms or more and multiple bathrooms, a system boiler might be your best option. 

When combined with an unvented cylinder, these boilers offer even greater power and efficiency. However, system boilers are larger than combi boilers, requiring more space for installation.

Heat-Only Boilers

Heat-only boilers, also known as regular or conventional boilers, are suitable for large families that need to use hot water across multiple taps simultaneously. These boilers work by storing hot water in a separate cylinder and require both a cold water tank and a hot water cylinder.

The advantage of heat-only boilers is that they can meet the high demand for hot water in large households with multiple radiators.

Furthermore, they are compatible with solar thermal systems, making them an environmentally friendly option.

Despite these benefits, heat-only boilers are typically the cheapest to buy but require more space for installation compared to combi and system boilers.

In summary, when choosing a boiler for a large family, it's essential to weigh the pros and cons of each type. Consider factors such as the size of your home, the number of bathrooms, and your family's hot water usage patterns before making a decision.

Best Boiler Brands for Large Houses

When it comes to choosing the best boiler for a big family, you'll want to look at some of the top brands to ensure you're getting a reliable and efficient option.

In this section, we will discuss six established boiler brands that are well-suited for large homes: Worcester Bosch, Baxi, Vaillant, Viessmann, Alpha, and Ideal.

Worcester Bosch Boilers

Worcester Bosch is a leading boiler brand in the UK, known for producing high-quality, energy-efficient boilers that suit large households. Their range of system and regular boilers cater to homes with multiple bathrooms, providing consistent hot water and heating throughout.

With a strong reputation for reliability and customer satisfaction, Worcester Bosch is a solid choice for big families.

Baxi Boilers

Baxi is another renowned boiler manufacturer in the UK market. They offer a variety of models, including combi, system, and regular boilers, capable of handling the demands of larger homes.

Baxi boilers boast eco-friendly features and user-friendly interfaces, making them an attractive option for environmentally conscious families. Additionally, Baxi is acclaimed for their after-sales service and support, which can give homeowners peace of mind.

Vaillant Boilers

Vaillant is a reputable brand that has been manufacturing boilers for over a century. With a focus on innovation and energy efficiency, their models consistently rank among the best in the industry.

Vaillant offers a range of combi, system, and regular boilers that can accommodate the needs of large families.

Their combination of German engineering and exceptional reliability make Vaillant boilers an attractive option for many homeowners.

Viessmann Boilers

Viessmann is a German company with a strong track record for producing high-performance, reliable boilers that are suitable for larger homes.

Their extensive range includes combi, system, and regular boilers with cutting-edge technology for optimal efficiency.

Viessmann models are designed for long-lasting performance, ensuring your family's comfort year after year.

Alpha Boilers

Alpha is a British brand that offers high-quality boilers at competitive prices. Their range includes combi and system boilers that cater to the needs of large families.

With models that are easy to install and maintain, Alpha boilers provide an excellent balance of performance and value for homeowners looking for a cost-effective solution for their heating needs.

Ideal Boilers

Ideal is a UK-based boiler manufacturer with a history of providing reliable and efficient heating solutions.

Their range of combi, system, and regular boilers is tailored to suit large households, offering flexible options that prioritise energy efficiency and user-friendly controls.

Ideal boilers are known for their quality and reliability, making them an excellent choice for homeowners seeking a dependable heating solution for their big families.

Boiler Efficiency

Energy Bill Impact

Boiler efficiency is a crucial aspect when considering boilers for big families, as having an energy-efficient boiler directly impacts energy bills. By opting for an energy-efficient boiler, big families can significantly save on their energy bills. Often, modern boilers come with an 'A' rating, meaning they are 90% or more efficient.


It is important to remember that efficient boilers demand less energy to provide the same level of heating compared to less efficient ones. This, in turn, leads to reduced costs and environmental impacts.

One must take into account both the initial cost of the boiler and the operational costs when deciding on the suitable option for a large family home.

Reducing Carbon Footprint

Environmentally-conscious families should also be attentive towards the minimisation of their carbon footprint. Reducing CO2 emissions from heating systems is pivotal to achieving this goal.

By selecting an energy-efficient boiler, big families can effectively diminish their CO2 emissions, contributing to a greener environment.

There is a range of energy-efficient boilers available in the market that help decrease the carbon emissions:

  • A-rated boiler provides 90%+ efficiency

  • B-rated boiler offers 86-90% efficiency

  • C-rated boiler delivers 82-86% efficiency

  • D-rated boiler gives 78-82% efficiency

  • E-rated boiler yields 74-78% efficiency

  • F-rated boiler has 70-74% efficiency

  • G-rated boiler encompasses below 70% efficiency

It is crucial to opt for at least an A or B-rated boiler for a big family dwelling, as these boilers offer not only higher energy efficiency but also a notable reduction in their environmental impact.

Boiler Sizing and Output

Boilers for Larger Homes

When selecting a boiler for a large house, it's essential to consider the output rating, typically measured in kilowatts (kW).

The greater the number of bedrooms and overall space in your home, the higher the kW output required to keep it warm and comfortable. A rough guide to determine an appropriate boiler size is to allow 1.5 kW for every radiator in the home.

It's worthwhile to consider other factors like insulation levels, the age of the property, and the local climate, as these can significantly impact the effectiveness of your chosen boiler.

Hiring a professional installer to assess your home's needs can ensure you select the best size and type of boiler for your large home.

Boilers for Multiple Bathrooms

Homes with multiple bathrooms often require more hot water than those with just one or two bathrooms. Therefore, it's vital to select a boiler with a sufficient output rating to successfully supply hot water to all bathrooms, especially during peak usage times.

A general rule of thumb is to allocate 3 kW of output for every bathroom in your house. This ensures that your boiler can meet your family's hot water demands without running out of hot water or causing undue stress on the boiler system.

Remember, though, that every home is different, and a professional assessment by a Gas Safe registered engineer can provide tailored advice for the ideal boiler size and output for your specific needs.

Additionally, using British English spelling and grammar is crucial for ensuring that your article appeals to the intended audience.

Boiler Installation and Maintenance

When it comes to selecting the best boiler for big families, one must consider not only the performance of the unit itself but also the associated costs and requirements of installation and maintenance.

In this section, we explore the factors that play a crucial role in determining the overall value of the boiler.

Boiler Installation Costs

Boiler installation costs can vary depending on factors such as the complexity of the installation process, the location of the property, and the boiler model chosen.

Typically, you can expect to pay anywhere between £1,500 and £2,500 for a new boiler and its installation. Keep in mind that higher efficiency boilers may come with a higher initial cost, but offer long-term savings on energy bills.

It is important to compare quotes from multiple fitters to ensure you receive the best value for your investment.

Safety Considerations

When selecting the best boiler for a big family, safety is of utmost importance. A well-functioning and safe boiler can prevent accidents and ensure the well-being of your family.

Firstly, it is crucial to choose a boiler from a reputable manufacturer that complies with British safety standards. Regular servicing and maintenance are necessary to keep your boiler in good working order.

If you have a gas boiler, you must be aware of the importance of hiring a Gas Safe registered engineer for installation, servicing, and repairs.

The Gas Safe Register is the official list of gas engineers who are legally allowed to work on gas appliances in the UK, including boilers.

If you're unsure about an engineer's credentials, you can always ask to see their Gas Safe Register ID card.

Moreover, to prevent accidents related to gas leaks, make sure you have a carbon monoxide alarm installed near the boiler.

Carbon monoxide is a colourless, odourless, and tasteless gas, which makes it impossible to detect without an alarm. Exposure to high levels can cause health issues, even proving fatal in extreme cases.

In addition, ensure proper ventilation around the boiler to avoid the risk of oxygen depletion. Blocked or inadequate air vents can lead to the build-up of dangerous gases. Regular checks of the air vents can ensure that they remain clear of debris and function optimally.

Lastly, familiarise yourself with the various safety features of your boiler, such as safety valves and pressure relief devices.

These components help to safeguard against potential hazards caused by issues like overheating or excessive pressure build-up.

In sum, when choosing the best boiler for your big family, always prioritise safety. Opt for a reliable boiler, get it installed by a Gas Safe registered engineer, and adhere to regular maintenance schedules.

Furthermore, installing carbon monoxide alarms, maintaining proper ventilation, and being familiar with your boiler's safety features will help to create a safer environment in your home. 

Hot Water and Heating Controls

Managing hot water and heating controls efficiently is pivotal for big families. Central heating systems often rely on a combination of radiators and a hot water cylinder to ensure consistent temperatures throughout the house.

Balancing these components effectively is key to meeting the individual heating and hot water requirements of each family member.

A well-designed heating control system will help regulate temperature levels and reduce energy consumption. Central heating systems are typically equipped with a timer and thermostat, enabling customisation of heating schedules.

For example, you might set the radiators to heat up in the morning, ensuring a comfortable temperature when everyone wakes up.

Smart thermostats can further improve energy efficiency and user convenience. Compatible with various types of central heating systems, these devices enable remote control of temperature settings through a smartphone or tablet. Additionally, some models feature learning algorithms that adapt to your family's routines and preferences.

Hot water cylinders play a crucial role in delivering a steady supply of hot water to big families. Choosing an adequately sized cylinder is essential for meeting the hot water demands of larger households.

You should consider factors such as household size, hot water usage patterns, and the type of boiler when selecting a suitable hot water cylinder.

Using heating controls in conjunction with hot water cylinders allows for better management of energy consumption. For instance, you can schedule the hot water cylinder to heat up only during off-peak hours, capitalising on lower energy tariffs and saving money on your bills.

In conclusion, having a well-configured heating control and hot water system is critical for large families looking to optimise their central heating. Harnessing the power of smart thermostats, efficient usage of hot water cylinders, and customisable heating schedules can significantly improve the overall energy efficiency and comfort levels within your home.

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Frequently Asked Questions

  • Are combi boilers good for large families?

    Combi boilers can be suitable for large families, but it largely depends on your household's hot water usage. If multiple people need to use hot water simultaneously, a system boiler might be a better option. System boilers have a separate hot water tank, catering to higher hot water demands usually associated with larger families.

  • Do big houses need two boilers?

    Typically, big houses don't require two boilers as long as the boiler system installed is adequate in size for the heating and hot water needs. However, homes with multiple radiators, bathrooms, and high hot water demands might benefit from installing two boilers, especially if the house has separate living spaces or wings.

  • What size boiler for a 3 story house?

    The ideal boiler size for a 3 story house depends on various factors, including the number of radiators, bathrooms, and your home's overall heating efficiency. It is best to consult a heating professional to recommend the appropriate boiler size for your specific requirements.

  • What size system boiler do I need for a 4 bed house?

    To select the right size system boiler for a 4 bed house, consider the number of bathrooms, radiators, and hot water usage. Typically, a system boiler with an output of 24-30 kW should work well for a four-bedroom house. Yet, consulting with a heating expert will ensure you pick the best size boiler for your needs.

  • How many radiators can a Worcester 8000 run?

    The Worcester 8000 comes in various power outputs, making it crucial to choose the appropriate model according to your home's heating needs. For example, the Worcester 8000 30 kW model can support around 15 radiators, depending on their size and your home's heat requirements.

  • How many radiators can a 30kW boiler run?

    A 30 kW boiler can typically run around 15 radiators, but this number can vary based on radiator size and home insulation. It's essential to evaluate your heating needs and consult a professional to determine the right boiler size.

  • How many kW boiler do I need for a 5 bed house?

    The ideal kW boiler for a 5 bedroom house varies depending on factors such as radiators and bathrooms. Generally, a 30-35 kW boiler may be suitable. However, it is best to consult with a heating expert to ensure you select the correct size boiler for your specific requirements.

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Article by
Stephen Day | Co-founder
Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.