Which is the Best Boiler for a Small House or Flat?

By: Becky Mckay

Updated: 18th April 2024

What's in this article?

What is a combi boiler?
Best gas combi boiler: Ideal vs Vaillant
More gas boilers for small houses or flats
Best electric boilers for a small house or flat
Elnur Mattira vs EHC Comet
Best electric boiler for a small house or flat
Gas or electric: Which is right for your home?
Get free boiler quotes today

Best Boiler for a Small House or Flat

In a small house or flat with 1 bathroom and around 10 radiators, a combi is the perfect boiler. They're highly efficient, heat water on demand and don't take up much space.

As there are so many benefits to installing a combi boiler, every manufacturer has their very own range. This can make it hard to know where to start. So, to help, we've compared the most reliable gas combi boilers from trusted brands that are perfect for small homes or flats.

Best Gas Combi Boiler: Ideal Vogue Max C26 vs Vaillant ecoTEC Plus 825

If you live off-grid, then an electric combi is worth considering.

Best Electric Combi Boiler: Elnur Mattira vs Electric Heating Company Comet

Live in a bigger property? Then compare the best boilers for a 3 bed house, best boilers for a 4 bed house or best boilers for a 5 bed house.

If you already have an idea of which type of combi boiler you’d like and don’t want to waste any more time, then we can put you in touch with up to 3 Gas Safe registered engineers in your area. Not only will you find someone who can install your new boiler quickly, but you can also compare their offers to ensure you’re getting the best price. Click the button below to receive your free quotes.

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What is a combi boiler?

Combi Gas Boiler
For small houses and flats, there's no better heating system than a combi boiler.

There are three types of boiler: combi, system and regular. Combi boilers are the only one which don't need any external parts (tanks in the loft or a hot water cylinder). This makes them compact heating systems so the only space you'll need to commit is a spare cupboard in the kitchen.

As well as being compact, they take hot water straight from the mains. This means they can act fast when you need heating or hot water.

The only downside is that by not storing domestic hot water in a cylinder – as regular and system boilers do – they can't meet high demands for heating. Which is why they’re great options for small houses and flats with one bathroom.

Best gas combi boiler: Ideal vs Vaillant

Ideal and Vaillant are amongst the most popular and trusted boiler brands around.

Let's start this head-to-head by getting to know both boilers a little better, find out their key features in the table below:

Boiler Feature	Ideal Vogue Max C26	Vaillant ecoTEC Plus 825
Central Heating Output	18 kW	20.4 kW
Domestic Hot Water Output	26 kW	25.4 kW
Seasonal Space Heating Efficiency Rating	92.7%	94%
ErP Efficiency Rating	A Heat, A Water	A Heat, A Water
Flow Rate	10.6 l/min	10.5 l/min
Standard Warranty	10 years	5 years
Maximum Extended Warranty	12 years	10 years
Dimensions in mm (HxWxD)	740 x 445 x 330	720 x 440 x 338
Mounting	Wall-mounted	Wall-mounted
Typical Price	£1,089	£1,152
Typical Installation Costs	£500 - £1,000	£500 - £1,000

Efficiency

The efficiency rating of a boiler tells you how well it turns fuel into heating and hot water. The higher the percentage, the less fuel it will need to heat your home.

Since Boiler Plus was introduced in 2018, all combi boilers must achieve efficiency levels of at least 92%. This means that all modern combi boilers are highly efficient and there really isn't much to separate them.

The Vaillant ecoTEC Plus 825 edges out the Ideal Vogue Max in this head-to-head with an efficiency of 94% compared to 92.7%.

Essentially, these percentages show you how much of each £1 you spend heating your home goes to waste. So, for every £1 spent heating a home with a boiler that's 94% efficient, only 6p is lost to the heat carried out of the home by waste gases.

Sizing (Output Rating)

Boiler Size
Boilers for small houses and flats are often too powerful. Which can lead to higher energy bills. So, to avoid that, you need to get boiler sizing spot on.

Boiler sizing is known as the output rating and is measured in kilowatts (kW). This is essentially a measurement of the boiler's power. Combi boilers have a separate output rating for central heating and domestic hot water. Both need to match the demands of your home.

In terms of the central heating output, the ecoTEC Plus 825 is slightly more powerful. 20.4 kW compared to 18 kW for the Ideal Vogue Max C26. Both of these are well suited to small homes and flats with around 10 radiators.

They can also meet the hot water demands of homes with 1 bathroom thanks to a DHW output of 26 kW for the Vogue Max C26 and 25.4 kW for the ecoTEC Plus.

Warranty

Now warranty is a great way to compare boilers. During the warranty period, the manufacturer will take a look at any faults and fix them if they're the result of the manufacturing process. Checking the length of the warranty can give a good indication as to how long you can expect the boiler to run reliably.

Ideal offers a standard warranty of 10 years on the Vogue Max, which is twice as long as the ecoTEC Plus warranty. Both manufacturers make it possible to extend the warranty when certain terms are met. So you could get a 10 year warranty on the Vaillant ecoTEC Plus or extend the Vogue Max warranty out to 12 years. Both very lengthy periods of time.

Boiler Guide’s customers deserve the best. Both in service and in products. If you buy a boiler from a Boiler Guide partner, you could receive up to 14 years of boiler warranty.

This will depend on the type of boiler, the brand and who you choose to install your product.

Price

In terms of price, there isn't much to separate these boilers. The average price of both is a little over £1,000 and the installation costs are likely to be very similar too. We recommend comparing boiler quotes to find the best deal on the installation of a new combi boiler.

More gas boilers for small houses or flats

While the Ideal Vogue Max C26 and Vaillant ecoTEC Plus 825 are great options for small homes or flats, they're not your only options. ATAG, Baxi and Worcester Bosch also have combi boilers well worth considering.

Boiler Model	CH Output	DHW Output	Typical Price
ATAG IC24	23.2 kW	26.6 kW	–
Baxi 825	21.2 kW	25 kW	£858
Worcester Bosch Greenstar 2000	20 kW	25 kW	£730

If you already know which boiler you’re interested in, don’t waste another second and find a qualified heating engineer to install it. At Boiler Guide, our team can put you in touch with up to 3 qualified heating engineers available in your area. This way, you’ll save hours of your time, and you can compare the offers from each engineer so you can rest assured that you’re not overpaying for your new boiler. Click the button below to get started.