Eco Happy (Solar Expert)

Published February 28, 2024

Choosing the right boiler for a large house with 4 to 5 bedrooms can be difficult. You want to ensure your home is warm throughout the winter but you’re worried that heating such a large space will lead to huge energy bills. If you have more than one bathroom, you’ll also need to find a boiler powerful enough to meet your hot water demands.

Well, we’ve used our expertise at Eco Happy, customer reviews, and test results from independent testing bodies to put together this list of the best boilers for a large house.

We’ll guide you through the qualities of each one, including crucial specifications like output ratings, and give you some advice on how to make the best decision.

The 5 Best System Boilers For A Large House

System boilers work in combination with a hot water cylinder to provide hot water and central heating to your home. A system boiler heats water directly from the mains to supply to the central heating system, and hot water is stored in the cylinder to be used for taps and showers.

System boilers are the best choice for large homes as they can supply hot water to several taps and showers at the same time. They can also comfortably heat homes with 4 or 5 bedrooms and 20 or more radiators.

Let’s take a look at the five best system boilers for a large home.

1. Vaillant ecoTEC Plus 630

Why it’s number 1: While it has a lower central heating (CH) output rating than some of the other system boilers on this list, it has the highest domestic hot water (DHW) output rating by far. It’s surprisingly rare to find a system boiler that has such high ratings for both, and when paired with its amazing efficiency ratings, putting this boiler in the top spot was a no-brainer.

  • Fuel type: Gas
  • Installation: Wall-mounted
  • Size (output rating): It has a CH output of 30.4 kW which makes it ideal for homes with up to 20 radiators, and a DHW output of 30.4 kW, meaning it’s a good choice for homes with two bathrooms.
  • Efficiency: This system boiler has an energy efficiency rating of 94% and an ErP A rating, making it one of the most efficient models on the market.
  • Warranty: 5-year warranty as standard. However, you can extend this to 7 or 10 years if your boiler is installed by a Vaillant Advance Installer.
  • Price (including VAT & installation): £2163 – £2,663

2. Baxi Platinum Plus 32

  • Fuel type: Gas
  • Installation: Wall-mounted
  • Size (output rating): Its CH output rating of32 kW means it can meet the hot water demand of a home with 20+ radiators. Plus, it has a DHW output rating of 18 kW and can comfortably supply multiple taps and showers with hot water simultaneously.
  • Efficiency: This highly efficient boiler has an efficiency rating of 93% and an ErP A rating.
  • Warranty: 10 years as standard.
  • Price (including VAT & installation): £1,832 – £2,332

3. Ideal Vogue Max S32

  • Fuel type: Gas
  • Installation: Wall-mounted
  • Size (output rating): The Ideal Vogue Max S32 has a CH output rating of 32 kW and a DHW output rating of 18 kW, making it the most powerful system boiler in the Vogue Max range.
  • Efficiency: It has an energy efficiency rating of 93.2% and an ErP A rating. It’s an excellent choice if you want to reduce your carbon footprint and the cost of your energy bills.
  • Warranty: 10 years as standard but it can be extended to 12 years when fitted by a Max Accredited Installer.
  • Price (including VAT & installation): £2,058 – £2,558

4. Ideal Logic Max S24

  • Fuel type: Gas
  • Installation: Wall-mounted
  • Size (output rating): The Ideal Logic Max S24 has a CH output rating of 24.2 kW and a DHW output rating of 24.2 kW, making it the least powerful system boiler on our list. It can heat homes with 10 to 15 radiators.
  • Efficiency: 94% and an ErP A rating.
  • Warranty: 10 years as standard.
  • Price (including VAT & installation): £1,849 – £2,349

5. ACV E-Tech W 36 Tri

  • Fuel type: Electricity
  • Installation: Wall-mounted
  • Size (output rating): It has a CH output rating of 36 kW and a DHW output rating of 18 kW, making it suitable for homes with two or more bathrooms and 15+ radiators.
  • Efficiency: This system boiler has a poor energy efficiency rating of 37% and an ErP D rating which is why it’s last on our list, even though it’s more powerful than the Vaillant ecoTEC Plus 630.
  • Warranty: 1 year which is exceptionally low and is another reason why its power output isn’t enough for it to appear higher on this list.
  • Price (including VAT & installation): £2,610 – £3,110

The 5 Best Regular Boilers For A Large House

Regular boilers, or conventional boilers, work alongside hot water cylinders and cold water tanks. They’re a great choice for large homes with two or more bathrooms, low mains water pressure, and up to 20 radiators.

They can be powered by gas, oil, or LPG, with gas and oil boilers being the most common.

The main downside of regular boilers is that they’re larger than system boilers and are more complicated to install and repair. This is because they need to be installed with an additional feed tank.

This list will help you choose the best conventional boiler for your large home.

1. Ideal Logic Max Heat H30

Why it’s number 1: It might not be the most powerful regular boiler on our list but it has more than enough power for a large home. The reason it takes the top spot is that it has a better warranty and price range than the Worcester Bosch Greenstar 8000 Life Regular 35, which is more powerful.

  • Fuel type: Gas
  • Installation: Wall-mounted
  • Size (output rating): The Ideal Logic Max Heat H30 has a CH output rating of 30.3 kW and a DHW output rating which is also 30.3 kW. This means it can easily deal with homes with two bathrooms and up to 20 radiators.
  • Efficiency: 93% and an ErP A rating.
  • Warranty: 10 years as standard or 12 years when installed by a Max Accredited Installer, which is high for a regular boiler.
  • Price (including VAT & installation): £1,917 – £2,417

2. Worcester Bosch Greenstar 8000 Life Regular 35

  • Fuel type: Gas or LPG
  • Installation: Wall-mounted
  • Size (output rating): It has a CH output rating of 35 kW, making it capable of heating up to 20 radiators. Its DHW output rating is 35 kW, which means it’s even more powerful than the Ideal Logic Max Heat H30. The reasons it’s not in the top spot are its slightly higher price range and shorter standard warranty.
  • Efficiency: 94% and an ErP A rating for lower energy bills and a greener home.
  • Warranty: 5 years as standard but it can be extended to 12 if it’s installed by a Worcester Bosch Accredited Installer.
  • Price (including VAT & installation): £2,346 – £2,846

3. Vaillant ecoTEC plus 430

  • Fuel type: Gas
  • Installation: Wall-mounted
  • Size (output rating): TheVaillant ecoTEC plus 430 has a CH output rating of 30.5 kW for heating homes with 20+ radiators, and a DHW output rating that’s also 30.5 kW. It’s a brilliant choice for large homes with high water demands.
  • Efficiency: 94% and an ErP A rating which means that just 6p is lost to heat carried out by waste gases for each £1 you spend on energy.
  • Warranty: 5 years as standard but can be extended to 7 to 10 years if you have it installed by a Vaillant Advance Installer.
  • Price (including VAT & installation): £1,967 – £2,467

4. Baxi 825 Heat

  • Fuel type: Gas
  • Installation: Wall-mounted
  • Size (output rating): This system boiler has a CH output rating of 25 kW which makes it best for homes with up to 15 radiators. This represents a 5.5 kW drop-off from the Vaillant ecoTEC plus 430. However, it does have a high DHW output rating of 29.5 kW, meaning it’s still an excellent boiler for a large home.
  • Efficiency: 93% and an ErP A rating.
  • Warranty: 10-year warranty as standard.
  • Price (including VAT & installation): £1,685 – £2,185

5. Vaillant ecoFIT Pure 425

  • Fuel Type: Gas
  • Installation: Wall-mounted
  • Size (output rating): Its 25.4 kW CH output rating only makes it suitable for homes with up to 10 radiators, which is why it comes bottom of our list of regular boilers. The reason it still has a place on our list is its 30.4 kW DHW output rating which allows it to provide hot water to multiple outlets at the same time.
  • Efficiency: It has the same ratings as the Vaillant ecoTEC plus 430 with 94% and an ErP A rating.
  • Warranty: 2 years as standard or 7 to 10 years if a Vaillant Advance Installer fits it for you.
  • Price (including VAT & installation): £1,776 – £2,276

The 4 Best Combi Boilers For A Large House

A combi boiler (combination boiler) supplies hot water on demand by heating the mains water supply which means it doesn’t require a cold water tank or hot water cylinder to function.

Combi boilers are compact which means they’re an excellent option for smaller homes where space is at a premium. They have a limited water capacity and can only effectively supply one outlet at a time. This means they’re not the best choice for larger homes with high hot water demands.

Still, brands like Worcester Bosch and Baxi make combi boilers that are powerful enough to heat and supply hot water to large homes. We’ve put together this list of the four best combi boilers for large homes.

1. Worcester Bosch Greenstar 8000 Life 50kW

Why it’s number 1: We think this is the best combi boiler for a large house because of its massive output ratings. There aren’t too many combi boilers out there that are as powerful as this, and it can easily handle homes with high hot water demands. While its warranty and price range made us pause for thought, there’s simply no ignoring that power.

  • Fuel type: Gas
  • Installation: Wall-mounted
  • Size (output rating): This condensing combi gas boiler has a huge DHW output rating of 50 kW. So, despite its small size, it’s suitable for homes with two to three bathrooms. Its CH output rating of 35 kW also means it can power a central heating system with up to 15 radiators.
  • Efficiency: 94% and an ErP A rating.
  • Warranty: 5 years as standard but if it’s installed by a Worcester Bosch Accredited Installer, this can rise to 12 years.
  • Price (including VAT & installation): £2,900 – £3,400

2. Ideal Vogue Max C40

  • Fuel type: Gas
  • Installation: Wall-mounted
  • Size (output rating): TheIdeal Vogue Max C40 combi boiler has a DHW output of 40 kW and a CH output of 32 kW which means it’s best for homes with up to 15 radiators and 2 bathrooms.
  • Efficiency: It’s only slightly less efficient than the Worcester Bosch Greenstar 8000 Life 50 kW with 93% and an ErP A rating.
  • Warranty: 10 years as standard or 12 years when fitted by an Ideal Max Accredited Installer.
  • Price (including VAT & installation costs): £2,123 – £2,623

3. Baxi EcoBlue Advance Combi 33

  • Fuel type: Gas
  • Installation: Wall-mounted
  • Size (output rating): If your property has two bathrooms, this combi boiler could be a good option as it has a DHW output rating of 33 kW. It’s also suitable for a home with up to 15 radiators due to its CH output rating of 29.6 kW.
  • Efficiency: The Baxi EcoBlue Advance Combi 33’s efficiency rating of 93% and ErP A rating make it an eco-friendly option for your large home.
  • Warranty: 10 years as standard.
  • Price (including VAT & installation): £2,205 – £2,705

4. Vaillant ecoTEC Plus 938

  • Fuel type: Gas
  • Installation: Wall-mounted
  • Size (output rating): The Vaillant ecoTEC Plus 938 has a DHW output rating of 38.7 kW and a CH output rating of 30 kW. This makes it a more powerful combi boiler than the Baxi EcoBlue Advance Combi 33. Yet, it finds itself bottom of our list because of its fairly short warranty and pretty high price range.
  • Efficiency: It also has a slightly better efficiency rating than the third-placed boiler with 94% and an ErP A rating.
  • Warranty: 5 years as standard or 7 to 10 years if installed by a Vaillant Advance Installer.
  • Price (including VAT & installation): £2,503 – £3,003

How We Chose The Best Boilers

So you’ve read our lists of the best system, regular, and combi boilers for a large house. But how did we choose the boilers we wanted to include? Let’s take a look.

Customer reviews

Often, the best way to assess the quality of a boiler is to see what customers have to say about it. After all, they’re the ones who rely on these products in their daily lives. Trustpilot is a good source for reviews as customers leave honest evaluations of the boilers they’ve bought along with a star rating out of five.

We looked for boilers with a four or five-star rating. We also searched for reviews containing keywords related to the most important features you’d need to consider when buying a boiler for a large house.

For instance, reviews containing words like “high output rating” and “energy efficiency” were clearly going to help us decide whether to include a boiler in our list or not.

Independent testing bodies

We also used independent testing bodies like Which?, Energy Saving Trust, and BEAMA (British Electrical and Allied Manufacturers Association) as resources for our list.

These bodies are objective and credible. They’re not affiliated with any specific boiler manufacturers and provide impartial and reliable test results and reviews.

The standardised testing procedures they use allow us to compare different aspects of boilers like their power, efficiency, reliability, and noise levels. This gives us access to valuable information based on factual data rather than marketing claims.

Factors To Consider When Choosing A Boiler For A Large Home

Here are the most important things for you to consider when choosing a boiler for a large house.

Home size

The size of your home is possibly the most important factor when choosing a boiler. You need it to have enough power to meet the needs of your central heating system and hot water demands. We’d recommend choosing a system boiler for a large house as they tend to be best equipped.

The general guidelines for system boiler size (in terms of kW) are as follows:

  • Up to 10 radiators and 1 bathroom: CH output of 15 to 26 kW and a DHW output of 24 kW.
  • 10 to 15 radiators and 2 to 3 bathrooms: CH output of 18 to 26 kW and DHW output of 24 kW.
  • 15 to 20 radiators and 4+ bathrooms: CH output of 26 to 40 kW and DHW output of 30.4 kW.

Efficiency rating

While most modern boilers tend to be fairly efficient, there are still some that are far more efficient than others. For example, condensing boilers in the UK have to be at least 92% efficient, meaning that 92% of the energy they use becomes usable heat.

Choosing a highly efficient boiler is great for the environment but it’s also good for your bank balance as reduced waste can significantly reduce your gas bill.

All of the boilers on our list are at least 93% energy efficient, so any one of them would be a good choice if you want to reduce your carbon footprint and save some money.

Budget

You also need to factor in the size of your budget when choosing a boiler for your home. Remember, it’s not just the price of the unit you need to consider but also the installation costs.

Generally, a combi boiler is less expensive to install than a system or regular boiler. This is because system and regular boilers tend to be fairly large and are quite complex to install.

If you’re on a tight budget, the least expensive boiler on our list is the Baxi 825 Heat at £1,685, including VAT and installation.

FAQs

Does heating a large house affect a boiler’s lifespan?

Heating a large house does not affect a boiler’s lifespan as long as you choose a boiler with the right CH and DHW output ratings. As with any boiler, it’ll need to be installed properly and regularly maintained. You also need to ensure the boiler is high quality and from a reputable brand (like the ones on our list).

Plus, you should find a boiler with a good warranty. This is a sign of the brand’s confidence in the longevity of its products.

How can I maximise the efficiency of my boiler in a large house?

To ensure your boiler is as energy efficient as possible, make sure your home is properly insulated to reduce heat loss. You could also consider using programmable thermostats and a smart heating system to get the most efficiency out of your boiler.

Is it possible to zone heating in a large house?

Yes, many modern boilers support multiple heating zones so that you can heat different areas of the house independently from each other. This is particularly beneficial in a large house where you may use certain rooms much more than others.

Final Thoughts

Although it can be tricky to find the perfect boiler that meets the heating and hot water demands of a large house, this list should point you in the right direction. Generally, system boilers are best suited to large homes and the Vaillant ecoTEC Plus 630 tops our list of the best system boilers.

However, regular boilers and combi boilers are also good options, as long as they have the right output ratings. If you do choose a regular or combi boiler, then our top picks are the Ideal Logic Max Heat H30 and the Worcester Bosch Greenstar 8000 Life 50kW.

Remember, as well as the output ratings, you also need to consider your budget and the energy efficiency of a boiler before you make your decision.

If you need help choosing the best large boiler for your home, contact Eco Happy – we’ll gladly help you narrow down your options.

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