Written by Stephen Day
Gas Safe Engineer
Updated: 19th November, 2025
The best boilers for a large 5 bedroom home, based on output, performance and hot water demand.
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A large 5 bedroom home needs a high output system boiler that can deliver strong heating and reliable hot water for multiple bathrooms.
This guide explains the best boilers for bigger homes in 2025 and how to choose the right size.
A 5 bedroom home is best suited to a high output system boiler paired with an unvented hot water cylinder.
The best boilers for large homes in 2025 combine high efficiency, strong hot water performance and long warranties.
Typical installation costs range from £2,500 to £4,500 depending on size and setup.
System boilers are typically the most suited boiler model type for larger UK properties.
For a large household, the clearest choice is a system boiler matched with an unvented cylinder.
System boilers deliver strong hot water flow and maintain pressure across multiple taps. This is essential for homes with three or more bathrooms.
They draw water directly from the mains, heat it efficiently and store it in a cylinder ready for use.
Larger homes use more water over shorter periods, so the combination of a powerful boiler and a large cylinder keeps water hot and available.
Our full list of top system models is available in the best system boilers guide.
Homes with older pipework or existing tanks may be better suited to a regular boiler.
Heat only systems work well in properties that already have loft tanks and older radiator layouts.
If the home already has this setup in place, replacing like for like can be the most practical option.
Most combi boilers cannot supply two or more bathrooms at the same time.
Even high output combis are unlikely to keep up with the hot water demands of a large 5 bedroom property.
System boilers are much more reliable for larger families.
To compare high performing combis, see our guide to the best combi boilers.
Below are the five strongest system boiler options for large UK homes in 2025 based on performance, reliability, warranty and suitability for multi-bathroom properties.
Boiler Model | Type | Output | Ideal For | Typical Price (2025) |
|---|---|---|---|---|
Worcester Bosch Greenstar 8000 System | System | 30 to 35 kW | Large homes with multiple bathrooms | £2,500 to £3,500 installed |
Vaillant ecoTEC Plus System | System | 25 to 37 kW | Larger properties needing strong flow rates | £2,400 to £3,400 installed |
Viessmann Vitodens 100 W System | System | 26 to 35 kW | Efficient heating for 4 to 5 bedroom homes | £2,300 to £3,300 installed |
Ideal Logic Max System | System | 24 to 30 kW | Reliable budget option for big homes | £2,000 to £2,800 installed |
Worcester Bosch Greenstore Unvented Cylinder | Cylinder | 150 to 300 litres | Stores hot water for busy households | £800 to £1,500 (cylinder only) |
You can explore more reliable models in our best boiler brands guide.
A high performance boiler known for strong efficiency and long term reliability. I
t is well suited to homes with multiple bathrooms and larger radiator systems.
Worcester Bosch offers long warranties and strong customer support, which makes this model a popular choice for big properties.
Vaillant’s ecoTEC Plus range delivers excellent hot water performance and high efficiency.
It works well with unvented cylinders and can manage the heating requirements of a large home.
Vaillant is known for quiet operation and consistent build quality.
The Vitodens 100 W is a highly efficient system boiler that uses a stainless steel heat exchanger for long life and strong corrosion resistance.
It is one of the most efficient boilers available and is well suited to homes with high heating demand.
This model is designed for performance and reliability, backed with a long warranty.
The Vogue Max is a strong option for homes with two to four bathrooms and is popular among homeowners looking for a balance of cost and warranty length.
The Baxi 800 System boiler is compact, reliable and built for long term performance.
It is a good choice for larger homes where durability and ease of maintenance are important.
Choosing the correct output is essential for heating performance and hot water availability.
Most 5 bedroom homes need a boiler between 30 and 40 kW depending on radiator count and insulation levels.
A typical 5 bedroom house with three or more bathrooms usually needs a 200 to 300 litre unvented cylinder to provide enough hot water during peak times.
As a rough guide, large homes often have 15 to 20 or more radiators, which increases the boiler output required.
You can estimate the right output for your home using our boiler size calculator.
Most large home installations fall between £2,500 and £4,500, depending on:
cylinder size
pipe upgrades
flue changes
access requirements
boiler output
System boiler installations can be more complex than combi swaps due to the cylinder and pipework involved.
Modern A rated boilers require less energy to heat large spaces and can reduce annual bills when replacing an older G rated model.
For full price ranges, see our breakdown of new boiler costs.
Large homes must be able to run several taps or showers at once without drops in temperature or pressure.
Look for warranties of 8 to 12 years to ensure long term reliability.
Smart thermostats and load compensation controls help maintain comfort while reducing running costs.
These offer the best long term durability and help maintain efficiency.
iHeat supplies and installs a range of high quality system boilers suitable for larger properties. Installations are carried out by
Gas Safe registered engineers, and homeowners can choose from leading manufacturers such as Worcester Bosch, Vaillant, Viessmann and Ideal.
iHeat provides fast online quotes and offers installation options for houses with higher heating and hot water demand.
The best boiler for a large household is almost always a high output system boiler paired with an unvented cylinder.
These systems handle multiple bathrooms, large radiator networks and high hot water demand with ease.
Worcester Bosch, Vaillant, Viessmann, Ideal and Baxi all produce strong options for 2025, and choosing the right size is essential for comfort and efficiency.
Last updated: 19th November, 2025
Written by Stephen Day
Gas Safe Engineer at iHeat
Stephen Day is a Gas Safe registered and FGAS certified engineer with over 20 years of hands-on experience in the heating, cooling, and renewable energy industry, specialising in boiler installations, air conditioning, and heat pump systems.
LinkedInArticles by Stephen Day are reviewed by iHeat’s technical team to ensure accuracy and reliability.
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