Best Small Combi Boilers

A boiler is one of the most essential items a homeowner will buy, and an asset throughout the winter months. Due to their efficiency, speed and compact size, small combi boilers are preferred by 70% of property owners in the UK. Best Small Combi Boilers Compare Boiler Quotes

What is the smallest combi boiler?

Small combi boilers are a godsend to those with little space to spare, and the preferred option for those residing in smaller properties, such as studio apartments and flats. When it comes to sourcing the smallest combi boilers on the market, we have you covered.

From discovering their benefits to the many variants available, to the main differences between combi and compact boilers, there is a lot to learn.

If you’re looking to invest in a combi boiler, get a quote here online now!

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What is a small combi boiler?

Gas combi boilers, or combination boilers, combine heating and hot water. The result? One compact unit. This nifty piece of apparatus promises hot water in an instance.

By heating water directly from the mains, it removes the need for a cold water tank and a hot water storage cylinder – both of which take up additional space.

Small combi boilers boast a power output spanning 24kW – 28kW. Since these devices can provide heating and hot water, they feature two sole heat output ratings. Best Small Combi Boilers Compare Boiler Quotes

The difference between a small combi boiler and a compact boiler

Most are under the impression a compact and gas combi boiler is the same. However, in the world of boilers, they boast very different features.

Combi Boilers

A small gas combi boiler provides power or heat determined in Kilowatts. In essence, this means it has a smaller yield to that of a traditional product, yet is still perfectly suited to smaller properties with fewer demands for hot water.

Two of the most renowned small boilers available today include the Worcester Bosch CDi Compact Combi Boiler and the Greenstar 25i Combi Boiler.

Compact Boilers

A compact boiler, unlike a combi boiler, is determined by its dimensions. This isn’t to say certain brands of small boilers aren’t compact too, it simply means compact boilers are designed specifically with smaller properties in mind – especially city centre apartments with limited space.

Compact boilers are therefore the perfect choice for customers searching for a boiler that will neatly stow away in a small space, such as in a kitchen cupboard. Best Small Combi Boilers Compare Boiler Quotes

The benefits of using a small combi boiler for your hot water

There are many benefits to small combi boilers, the main being there is less space required to house them.

Combi boilers are extremely compact in style, and they don’t feature an independent hot and cold water storage tank. This allows them to supply a continuous stream of hot water. These two features alone make them the perfect choice for smaller homes.

In addition to their size and performance, they use a clean water supply. This means the water isn’t stored in a tank and instead, comes straight from the mains, avoiding common traditional boiler issues such as sludge build-up.

On top of this, they boast impressive efficiency levels, and those who install combi boilers into their home will benefit from lower gas and heating bills.

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The smallest combi boilers

There are plenty of small combi boilers to choose from. We’ve featured two of the most reputable brands below.

1. Worcester Bosch Greenstar CDI Compact 28kW

As one of the most celebrated brands today, it’s little wonder the Worcester Bosch Greenstar CDI Compact 28kW made it to the top of our list. Due to its high-tech features and compact dimensions, it’s a top choice for homeowners and installers alike – especially homes in the UK with smaller spaces. Best Small Combi Boilers Compare Boiler Quotes

As well as being one of the smallest combi boilers available, it’s also one of the most cost-effective options from Worcester Bosch. Often referred to as an entry-level boiler, it’s extremely easy-to-use, easy to install and gets five stars for efficiency.

This boiler’s digital interface, despite boasting the height of innovation, is simple to operate and has been awarded the ‘Best Buy Award from Which?’.


  • The option of a 28kW or a 32kW version
  • 10-year warranty
  • A-rated boiler
  • High efficiency
  • Lower heating and energy bills
  • 10-year guarantee
  • Winner of the Which? ‘Best Buy Award’ for 10 consecutive years


  • Simple interface
  • Entry-level boiler

Final thoughts:

A great boiler for those looking for a simple yet efficient product that stands the test of time and one that promises to squeeze into the smallest of spaces. You can always ask for a compact boiler whenever you are getting any boiler quotes.

2. Ideal Logic Plus 24kW

The Ideal Logic Plus 24, a sister product to the +30 and +35 range, comes in the shape of a gas combi boiler and is another best buy.

This British-made product is a popular choice for homeowners looking to invest in a highly efficient, easy-to-use boiler, boasting a simple digital display. This is an asset to those wishing to be notified of any boiler faults. Best Small Combi Boilers Compare Boiler Quotes

Operating to an A-rating efficiency standard, the Ideal Logic Plus 24 Combi Boiler meets all European Union regulations and is ErP compliant. great for low-cost central heating.

This is another great entry-level option, featuring flow rates of 9.9 litres and a central heating output of 24kW. Due to its dimensions and specifications, it’s a popular choice for smaller homes, such as apartments, and single occupancy properties featuring one bedroom and one bathroom.

Measuring a height of 700mm, a width of 395mm and a depth of 278mm, this particular model boasts a seven-year warranty, which safeguards you should any issues arise in this period, whilst the after-sales care is said to be second to none.


  • Quality after-sale customer support
  • British-made
  • Compact
  • Warranty is 7 years
  • Highly efficient
  • Lower heating and gas bills
  • Instant hot water
  • Easy installation


  • Suited to smaller properties

Final thoughts:

Another top choice for an entry-level combi boiler, perfectly suited to smaller properties, especially those limited in space.

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Buyer’s guide

When it comes to buying a boiler, there are several factors you should take into consideration as well as installation cost.


There are many quality boiler manufacturers to choose from. When considering a brand, it’s important to consider the installation. Quite often, technicians have a preferred brand, and opting for known products makes the installation a much smoother process. Today’s reputable models include: Best Small Combi Boilers Compare Boiler Quotes

  • Worcester Bosch
  • Ideal Boilers
  • Potterton
  • Baxi 600
  • Vaillant Ecofit
  • Vitodens 111 w


The warranty of your boiler should never be overlooked. If anything is to go wrong, this protects you from unnecessary fees. You need to protect your boiler warranty with a service every year.

For example, a boiler with a ten-year warranty, such as the Worcester Bosch Greenstar 25i range will safeguard you against any issues (whether a repair or a replacement) that happen in the first ten years of owning the equipment.

Brands without good warranties should be avoided. If anything is to go wrong, it will be your responsibility to front the bill, and boiler fixes and replacements aren’t cheap! Always ensure you get a boiler service every year, we can’t stress this enough! Best Small Combi Boilers Compare Boiler Quotes

Opting for a lower-priced brand to save a small amount of money will likely end up costing a lot more in the long-run. As a minimum, choose a boiler brand that offers a warranty of 7 years or more.


Installing a new boiler into your apartment or house need not be a bothersome procedure. Providing you choose a quality product from a reputable brand and have the tools and expertise to install it yourself, or know of an expert installer, this process won’t take long at all.

If you have a particular boiler in mind, you can request installation boiler quotes before committing to the purchase. If slightly higher, this shouldn’t deter you from buying the boiler you want, as a quality boiler will prove more cost-effective in the long-run.

The average installation cost is between £1,800-2,000. This is dependent on the brand, the style and how difficult the installation is. For example, if you need to remove an existing boiler, this will be a bigger job and may cost slightly more.

Before buying a gas boiler, it’s a good idea to discuss options with a specialist, this way you will guarantee you pick the best product for your needs. To ensure you get the best quotes possible, don’t be afraid to ask for more information. There some fantastic prices on the internet right now

Before you shell out for the full installation cost, don’t let the boiler you have in mind may be the wrong option for your home entirely! Best Small Combi Boilers Compare Boiler Quotes

Availability of parts

If your new boiler stops functioning in the way it should, due to a faulty part, such as a diverter valve or heat exchanger, you will need to fix or replace this part. Prices for parts can sometimes be costly. This is when calling in a service technician is a must. Things like this can also be prevented by getting a boiler service every year.

Whether you or they order the part in question, it’s important to find a quality supplier who can deliver the item fast. The sooner your boiler is back up and running the better – a house without water (especially hot water) isn’t a happy one!

With this in mind, it is essential to choose a boiler from a reputable brand and one linked to an entire network of installers, technicians and easily-accessible parts.

Choosing a less well-known brand will likely result in a more expensive, lengthy fix, partly because specialist parts and technicians are hard to find.

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What size are combi boilers?

The smallest existing boiler on the market is the Worcester Bosch 32CDi Compact Combi Boiler. It measures 280mm in diameter, 390mm in width and 690mm in height. This is the smallest piece of boiler equipment the Worcester Bosch brand has ever produced. Their prices are pretty good too!

Due to its size alone, it’s an ideal option for studio apartments and small houses, and can easily be tucked away in kitchen cupboards.

When it comes to determining the dimensions of the boiler you need for your home, consider how many showers and tap water you use, and how many bathrooms your property has. For best results, use your existing central heat output to give you an indication of what boiler style you need. Best Small Combi Boilers Compare Boiler Quotes

How many years should a combi boiler last?

If from a reputable brand and maintained well, the majority of contemporary gas boilers last between 10 and 15 years. If your current boiler is nearing this age, it may be time to upgrade.

That being said, the exact date you should replace your boiler isn’t set in stone. It all comes down to the brand, how much it has been used and how well you have maintained it.

What is the smallest boiler you can buy for hot water?

The answer is the 32CDi Compact Combi Boiler.

This one is currently the smallest boiler on the market to date. Measuring just 390mm in width, 690mm in height and 280mm down, this is Worcester Bosch‘s most compact boiler.

Due to its petite frame, this range can be installed in minute spaces, such as kitchen cupboards.

Can I fit my own combi boiler?

The simple answer? Yes. Although, fitting your one yourself isn’t advised if you’re unsure of how to complete this operation. That being said, DIY gas-work is legal, so if you have the skill sets to do so, you may fit your combi boiler.

For safety, certain UK boiler manufacturers prefer you to invest in the assistance of their specialist team, insisting all who are employed by them have a qualification in this area or have undergone specific training. If you choose to fit the boiler yourself, you may forfeit the warranty.

Although combi boiler installation is relatively easy, it can be on the pricey side, especially if you need to remove an old water tank before installing the new boiler.

That being said, if it is a quick fix job, it can take under two hours, and once installed, providing you maintain them well, they will give you years of usage.

They will also lower your gas bills dramatically, often by up to around £240 per year with certain models. In addition, having a combi boiler installed in your home may increase your property’s value.

What is the warranty period?

When choosing new products or replacement, it’s important to pick a product that offers a great warranty. Always make sure that the warrant is included in any small boiler prices you are given.

The warranty time limit is a key factor to take into consideration when deliberating between brands. It is what ensures the product is covered should anything go wrong, whether it needs to be repaired or requires new parts.

The majority of boiler manufacturer warranties range between seven and ten years. For best results pick one that lasts as long as possible. Best Small Combi Boilers Compare Boiler Quotes

What should I expect to pay for a boiler?

New boilers are one of the most imperative pieces of equipment in your home, which is why it’s important to invest in a quality product. If not, you’ll likely end up spending more money in the long run, either on repairs or a replacement. Prices vary in each range so make sure you are aware of the differences.

Combi boilers are the most prevalent choice for homeowners in the UK. Why? They’re efficient, speedy and supply hot water in an instance. The main reason for their popularity, however, is their small size.

When it comes to prices, this varies on the type and brand you buy. Today’s quality combi boilers span between £500 and £2000.

The more expensive styles often boast more tech features and are suited to bigger homes. Whilst the low-cost options are perfect for those looking to buy an entry-level product. For best results, make sure you always request several quotes.

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What size is a small boiler?

The majority of small gas boilers typically sit under 25kw – this is an ideal power output for studio apartments, flats, and smaller houses. In certain cases, this depends on how many people are living in the house, how many radiators there are and how much water is used on average.

As an example, a gas boiler with a 25kW output can be used to power a property with three bedrooms. If you’re a savvy-saver or spend a lot of time away from home, a smaller boiler could be the ideal option.

Each boiler range available on the market today is specified by CHW (central heating output), and the flow rate.

If you reside in a property that has more than three bedrooms, a large number of radiators and a bigger family, you will need to invest in a DHW (domestic hot water) boiler, with a higher central heating output. This is a necessity if taps and showers tend to be running at the same time.

When should I buy a small combi boiler? Best Small Combi Boilers Compare Boiler Quotes

There are many reasons to purchase a new boiler, one of the main reasons being when your existing boiler is no longer cost-effective to repair. Another, if it is wasting energy – several aged boilers won’t switch off when they have reached the correct temperature. This is what is known as a ‘dry cycle’.

You may also wish to invest in a new combi boiler if your existing product doesn’t feature a thermostat, which prevents you from controlling the heating, and wastes a lot of energy.

If you have one of the old gas combi boilers with a pilot light (a visible flame), this is a sure sign your boiler is wasting a great deal of energy. Finally, if you’re renovating an existing house, whether you have just bought it or you’re about to sell it, this is the perfect time to get a replacement.

Small combi boiler quotes

If you need a small boiler and are looking to get a brand new one. Look no further than We can provide you with a quote within minutes online. If you are unsure about anything make sure you contact our lovely customer service team who would be more than happy to help you with your quotes. All online quotes are fixed and we can arrange for installation the next day. Try it now and see how much your new small boiler will cost you today.

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