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Last updated: 10 October 2023

25kW Boilers – Everything You Need to Know

25kW boiler

Are you looking for a new 25kW boiler to heat your home? Well, look no further. Our GreenMatch experts have reviewed some of the highest quality 25kW condensing boilers and compiled them here. These boilers are best suited for a home with 10 to 15 radiators and 1 to 2 bathrooms.

Is your home bigger or smaller than this? Then perhaps you may need a 24kW boiler or a 28kW boiler. No matter what output size you need, we’ve got you covered. We’ll help you find your next new boiler by comparing the new boiler cost, boiler type, boiler brand, fuel, efficiency, and more. Read on to find a 25kW boiler that suits your home.

A major factor when it comes to deciding whether or not you should replace your boiler is the price. But what if we told you that you could save £630 on your energy bill every year if you replace your old gas boiler with a new A-rated one? That definitely improves the cost-effectiveness of replacing your boiler!

If you’re interested in replacing your boiler with a more efficient model then GreenMatch can help you find the best price. By clicking the button below you can receive up to 4 free quotes from installers in your area and objectively compare them to make sure that you get the best deal. And what’s more, you’re under no obligation to accept any of them, so you’ve got nothing to lose.

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25kW System Boilers

A system boiler is a type of boiler that provides central heating and domestic hot water with the help of a hot water cylinder. While this does mean system boilers can meet higher hot water demands, the water cylinder does require additional space.

A 25kW system boiler is best suited for a home with 10 to 15 radiators and 2 bathrooms. You can find 3 diverse options for a 25kW system boiler below. You can compare them by their manufacturer, energy efficiency, cost and fuel type.

1. Worcester Bosch Greenstar Danesmoor 18/25 System Oil Boiler

This Worcester Bosch 25kW boiler is ERP A-rated and runs on oil. It’s a great choice if your home already runs on oil because you won’t need a new oil tank. The Greenstar Danesmoor is both EasyControl compatible and solar thermal compatible. So if you’re looking to transition to more renewable energy, this boiler can help you start.

    • Efficiency: 90%
    • LPG Compatible: No
    • Central Heating Output: 25kW
    • Warranty: Up to 5 years
    • Estimated price (excl. installation): £1,893 (inc. VAT)

2. Biasi Advance Plus 7 25kW System Gas Boiler

The Biasi Advance Plus 7 25kW boiler is designed for quick and easy installation. It features a simple-to-use control panel, built-in frost protection, and self diagnostics . All of the Advance Plus models are equipped with an edge quad processor technology which means that if your boiler develops a fault, it can continue to work safely without needing to shut down.

    • Efficiency: 92%
    • LPG Compatible: Yes
    • Central Heating Output: 24.4kW
    • Warranty: 7 years
    • Estimated price (excl. installation): £650 (inc. VAT)

3. Vaillant ecoFIT pure 625 System Gas boiler

This 25kW condensing boiler, made by Vaillant, has been Quiet Mark approved – this means it’s quieter than most boilers similar to it. It’s not just quiet either, it’s also smart. So for the times that you don’t need as much heat, it will turn itself down to 20% of its maximum output – this way you’ll use less energy and save money. The unit’s components are also built to last, meaning you can expect peace of mind for the lifetime of the model.

    • Efficiency: 94%
    • LPG Compatible: No
    • Central Heating Output: 25.4kW
    • Warranty: 10 years
    • Estimated price (excl. installation): £1,243 (inc. VAT)

25kW Combi Boilers

Combi boilers are one of the most compact boiler types. This is because they combine the functionality of a water heater and a central heating boiler into a single unit – eliminating the need for an additional hot water cylinder. Hence, if you’re looking for a boiler for a small house, a combi boiler may be the best choice.

A 25kW combi boiler will generally support the heating and hot water demands of a home with up to 10 radiators and 1 bathroom. But where do you start when it comes to choosing a specific model for your home? Thankfully, we’ve already gone through and reviewed a range of combi boilers with a domestic hot water output of 25kW for you, so here are 3 options from some of the best manufacturers to get you started:

1. Glow-worm Energy Combi 25kW Gas Boiler

The Energy combi boiler from Glow-worm is a great option, especially if you’re looking for something under £1,000. One of the main highlights of this 25kW boiler is that it is able to adapt to your actual heating and hot water demands, meaning that you can reduce the amount on your heating bills. It is also Quiet Mark approved so you’ll barely notice it working away in your home.

    • Efficiency: 94%
    • LPG Compatible: Yes
    • Central Heating Output: 18kW
    • Domestic Hot Water Output: 25.7kW
    • Warranty: 7 years
    • Estimated price (excl. installation): £775 (inc. VAT)

2. Vaillant ecoTEC plus 825 Combi Gas Boiler

The ecoTEC plus 825 is a great choice if you’re conscious of your carbon footprint. Due to modern technology, this boiler is able to achieve high efficiency at the lowest emissions. What’s more, if you’re interested in renewables, this boiler is compatible with the aroTHERM air to water heat pump hybrid system.

    • Efficiency: 94%
    • LPG Compatible: Yes
    • Central Heating Output: 20.4kW
    • Domestic Hot Water Output: 25.4kW
    • Warranty: 10 years
    • Estimated price (excl. installation): £1,152 (inc. VAT)

3. Worcester Bosch Greenstar Heatslave II 25/32 Combi Oil Boiler

This Worcester Bosch 25kW combi boiler is a great choice for those who are not connected to the gas grid and need an alternative fuel source. Oil boilers almost always are variable in output, with this specific model being able to adjust from 25-32kW. There is also a smaller size that varies from 18-25kW if you need slightly less power for your home.

Even though oil boilers unfortunately aren’t the best for the environment, this particular model does come with an eco hot water mode to help increase efficiency and save you energy.

    • Efficiency: 90%
    • LPG Compatible: No
    • Central Heating Output: 25 – 32kW
    • Hot Water Flow Rate: 22l/m
    • Warranty: Up to 5 years
    • Estimated price (excl. installation): £2,395 (inc. VAT)

As combi boilers are the most popular boiler type in the UK, there are a lot of different models to choose from. This can be overwhelming to say the least. It’s advisable to always check with a professional heating engineer what they would recommend for your home, as this will ensure you don’t waste money on an unsuitable boiler.

Simply click the button below to get up to 4 free quotes from installers in your area. Receiving multiple offers means you can get a better idea of the total cost (incl. installation) of boilers on the UK market and objectively choose the best one for you. This way you make sure you’re not wasting money or spending too much!

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25kW Conventional Boilers

Heating engineers typically do not recommend buying a conventional boiler (also known as a regular or heat-only boiler) if you don’t already have one installed. This is because it requires the installation of additional tanks in the loft and a hot water cylinder. This makes conventional boiler installation complex and disruptive. Your alternative options include a combi or system boiler.

A 25kW conventional boiler is best suited for homes with 10 to 15 radiators and up to 2 bathrooms. While conventional boilers are an older boiler type, there are still many modern models on the market. We’ve reviewed and compiled some of the top 25kW conventional boilers for you to choose from.

1. Baxi 825 Heat 25kW Conventional Gas Boiler

A standout feature of this 25kW boiler from Baxi is that it’s been fitted with a magnetic filter which helps to avoid blockages. This model is also already certified to work with a 20% hydrogen blend, which is better for the environment. This means that when the UK’s gas grid changes to support hydrogen blends you won’t have to worry about upgrading your boiler.

    • Efficiency: 93%
    • LPG Compatible: No
    • Central Heating Output: 25kW
    • Warranty: 10 years
    • Estimated price (excl. installation): £885 (incl. VAT)

2. Vaillant ecoFIT Pure 425 Conventional Gas Boiler

This 25kW boiler from Vaillant comes with a full range of heating control options. It’s simple to use and there’s also the option of downloading its smartphone app, giving you maximum control over your heating. Furthermore, this boiler can recognise when you’re using more heat than you need, and in these instances will reduce itself to 20% of its maximum output. This will greatly help with reducing your heating bills.

    • Efficiency: 94%
    • LPG compatible: No
    • Central Heating Output: 25.4kW
    • Warranty: 10 years
    • Estimated price (excl. installation): £976 (incl. VAT)

3. Worcester Bosch Greenstar Danesmoor 18/25 Conventional Oil Boiler

Sometimes it can feel like modern technology can be unnecessarily complicated. That’s why Worcester Bosch tries to keep it simple with their easy-to-use controls. Another great plus to this 25kW boiler is that it’s fully compatible with solar technology, meaning you can reduce your carbon emissions.

    • Efficiency: 90%
    • LPG compatible: No
    • Central Heating Output: 18-25kW
    • Warranty: 2 years
    • Estimated price (excl. installation): £1,700 (incl. VAT)

Checking with a professional whether a conventional boiler is appropriate for your home or not is always a good idea. They can give you accurate advice and prevent you from pouring money down the drain on a boiler that doesn’t make sense for your circumstances. Another excellent idea is to compare offers from different installers to ensure you’re getting the most out of your money.

By clicking the button below, you can receive up to 4 free quotes from installers in your area and select the one which is best for you.

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25kW Biomass Boilers

A 25kW biomass boiler can offer a great low-carbon heating solution for your home. A biomass boiler uses organic fuel, such as wood pellets, logs, or chips, to heat your home. This process has the potential to be carbon neutral, due to the fact that burning wood only releases the carbon absorbed by the tree during its lifetime.

However, even though this is an advantage of having a biomass boiler, it’s important to keep in mind that there is an issue with trees being cut down quicker than they’re being regrown. You should always check with your supplier how they handle this issue and whether or not their procedures are sustainable.

When choosing a biomass boiler for your home you’ll be able to choose between boilers with manual fuel loading or more sophisticated ones with automated fuel delivery systems. Generally, the automatic biomass boilers cost more. Thankfully, there are grants available for biomass boilers to help you reduce the upfront costs.

Here are some 25kW biomass boiler options for you to consider based on each fuel type:

  • Grant Spira
    • Biomass Type: wood pellets
    • Max Energy Efficiency: 97%
    • Estimated Price: £11,000 – £12,500
  • Windhager LogWIN Premium Touch
    • Biomass Type: logs
    • Max Energy Efficiency: 92%
    • Estimated Price: £7,000 – £10,000
  • Froling T4e
    • Biomass Type: chips
    • Max Energy Efficiency: 95%
    • Estimated Price: £8,000 – £14,000

It’s important to note that biomass boilers are best suited for larger homes in rural areas. This is because they require a lot of space and also because there are restrictions in certain parts of the UK. In addition to this, biomass boiler installations can be complex. This is why it’s always important to contact a qualified heating engineer to make sure everything goes smoothly and you avoid any unnecessary costs.

At GreenMatch, we can provide you with up to 4 free quotes from qualified heating engineers who will be familiar with the regulations regarding biomass boilers in your area. Simply select your region button below to get started.

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FAQ

Hannah Maza
Written by Hannah Maza, Writer

As a writer with a deep understanding of low-carbon energy systems, Hannah aims to breakdown knowledge barriers and share insights to empower individuals in their pursuit of creating more environmentally conscious homes.

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