Which Boiler Is Best?

When deciding which boiler will be best for your home, the most important factors are the type of boiler and brand.

According to the Energy Savings Trust, a new energy efficient boiler will save you up to £350 a year by shrinking your energy bills.

To help you, our boiler experts have tracked down the best boilers, based on independent research from Which?, thousands of real user reviews on Trustpilot, and our own surveys of qualified engineers up and down the UK.

Read on to find out more, or save time by completing the form at the top of this page, and get bespoke boiler quotes for your home from the most trusted boiler installers in your area.


In This Guide to the Best Boilers in 2018:



Which Type of Boiler is Best for You?

best boiler for you

The type that will be best for you depends on the size of your home and your central heating requirements. There are three main types of boilers suitable for UK households:

Domestic boilers can be fired by gas, oil, LPG or electricity.


Best Combi Boiler

Combi boilers are the most compact way of heating homes, and are designed for smaller homes.

A combi boiler provides heating and hot water directly from the boiler, which is great if you like a powerful shower: the hot water is delivered through your taps or shower head at mains pressure and there's no need for a pump. They're also the ideal choice if your home has limited space or you simply want to save energy and cut bills. In fact, combi boilers are the most popular type of heating system used in UK homes.

The icing on the cake is that combination boilers are generally cheaper to have installed than other types of boilers because there is no tank and less pipework involved.

Here are the pros and cons of combi boilers, in a nutshell:

  • Pros
  • ✓ Energy efficient
  • ✓ Cheap to run and install
  • ✓ Compact (ideal for small homes)
  • ✓ Easy to find experienced engineers
  • ✓ Mains water is more hygienic than water tanks
  • Cons
  • ✗ Dependent on mains water pressure
  • ✗ Many people cannot shower at once
  • ✗ A broken boiler means no central heating


What Is the Best Combi Boiler?

To find the best combi boilers, we compared models from the UK's leading boiler brands, based on what matters most: build quality, value for money, brand reliability, ease of servicing and energy efficiency (which means lower monthly bills).

The best combi boilers in 2018 are:

Product Name

Brand

Mounting

Fuel Type

Efficiency Rating

Average Price

Vortex Pro Internal Combi 21e
Grant
Floor-standing
Oil
A
£2,060.00
ecoTEC plus 838
Vaillant
Wall-mounted
Gas or LPG
A
£1,330.00
Vitodens 100-W Combi 30kW
Viessmann
Wall-mounted
Gas or LPG
A
£960.00
Vitodens 200-W Combi 35kW Weather Comp
Viessmann
Wall-mounted
Gas or LPG
A
£1,300.00
Greenstar Highflow 44 0 CDi ErP
Worcester-Bosch
Floor-standing
Gas or LPG
A
£1,900.00


How does a Combi Boiler Work?

All of the best combination boiler brands work in a similar way. This diagram shows how the system works in relation to your home:

combi boiler explainer

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Best Conventional Boiler

Combi boilers are best for smaller homes or homes without much storage space.

Conventional boilers, also known as a regular boiler or open vent boiler, also heat your home's water and radiators. They require a cold water storage tank in the loft along with a tank that maintains the central heating system’s water level.

They take up a fair amount of space, so your home or attic will need to be big enough. Here are the main pros and cons of a conventional boiler:

  • Pros
  • ✓ Power showers are always an option
  • ✓ You can run many hot showers at once
  • ✓ Compact (ideal for small homes)
  • ✓ Back-up option of an immersion heater
  • ✓ Easy to use and reliable
  • Cons
  • ✗ Need more space than combi boilers
  • ✗ Storing water is less efficient, and costs more
  • ✗ Water can take time to heat up once it runs out



What Is the Best Conventional Condensing Boiler?

Brand

Product Name

Mounting

Fuel Type

Efficiency Rating

Average Price

Grant
Vortex Eco Wall Hung Internal 16-21
Wall-mounted
Oil
A
£1,330.00
Ideal
Logic+ Heat 24
Wall-mounted
Gas
A
£830.00
Vaillant
ecoTEC plus 430
Wall-mounted
Gas
A
£930.00
Viessmann
Vitodens 100-W Open vent 26kW WB1B
Wall-mounted
Gas or LPG
A
£950.00
Worcester-Bosch
Greenstar FS 30CDi Regular ErP
Floor-standing
Gas or LPG
A
£1,460.00


How does a Conventional Boiler Work?

The image below explains how a conventional boiler will work in your home:

conventional boiler explainer



Best System Boiler

System boilers are the best option for homes already with a traditional heating and hot water system.

With a system boiler, the key heating and hot water components are built into the boiler. However it still needs a cylinder for storing hot water.

Unlike a conventional boiler, you don’t need a tank in your loft, but you don’t get hot water instantly and it can run out.

  • Pros
  • ✓ Ideal for homes with 2 bathrooms
  • ✓ No need for a separate water tank
  • ✓ Economical to run
  • ✓ Fairly compact (no cold water tank)
  • ✓ Compatible with solar water heaters
  • Cons
  • ✗ Pre-heat water to set times
  • ✗ Can run out of hot water
  • ✗ Need more space than combi boilers



What Is the Best System Boiler?

Brand

Product Name

Mounting

Fuel Type

Efficiency Rating

Average Price

Grant
Vortex Eco Utility System 26-35
Floor-standing
Oil
A
£1,680.00
Vaillant
ecoTEC plus 637
Wall-mounted
Gas or LPG
A
£1,300.00
Viessmann
Vitodens 100-W System 30kW
Wall-mounted
Gas or LPG
A
£1,050.00
Viessmann
Vitodens 200-W System 26kW Weather Comp
Wall-mounted
Gas or LPG
A
£2,630.00
Worcester-Bosch
Greenstar 35CDi Classic System ErP
Wall-mounted
Gas or LPG
A
£1,200.00


How does a System Boiler Work?

The image below explains how a system boiler will work in your home:

system boiler explainer

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Best Gas Boilers

Gas boilers are ideal for homes with a main gas connection.

For homes connected to the UK national gas network, most use a gas-fired boiler to fuel their central heating system and supply hot water to their taps.

There is a wide range of gas boilers to choose from, and they come in combi, conventional and system models.

  • Pros
  • ✓ Cheap and less variable prices
  • ✓ 90% energy efficient
  • ✓ Gas heats water faster than electricity
  • ✓ Gas is cleaner than oil
  • Cons
  • ✗ Need a home gas supply
  • ✗ Gas leaks are dangerous



What Are the Best Gas Boilers?

Brand

Product Name

Type

Mounting

Efficiency Rating

Average Price

Ideal
Logic System 24
System
Wall-mounted
A
£800.00
Vaillant
ecoTEC plus 430
Conventional
Wall-mounted
A
£930.00
Viessmann
Vitodens 100-W Combi 26kW
Combi
Wall-mounted
A
£900.00
Worcester Bosch
Greenstar 27i System ErP
System
Wall-mounted
A
£990.00
Worcester Bosch
Greenstar 30i ErP
Combi
Wall-mounted
A
£950.00




Best Oil Boiler

Oil boilers are perfect for homes in remote areas (without gas).

For the estimated 4 million households in the UK who aren’t connected to the gas network, oil boilers are an alternative option for heating a home. Just like gas boilers, oil-fired boilers use oil to heat water and supply central heating through your radiators and hot water through your taps and showers.

For an oil boiler to function, you’ll need to have a constant supply of oil delivered to your property throughout the year and stored in an external tank. These tanks can typically hold enough oil to fuel a home’s boiler for up to 9 months.

Most oil boilers are conventional or combi, although many oil-fired combi models will still need an internal hot water tank to supply water. Fewer brands produce oil boilers than gas boilers, but there is still a good choice on the market.

  • Pros
  • ✓ Cheap to buy and install
  • ✓ More energy efficient than electricity
  • ✓ Ideal if your home is without gas
  • Cons
  • ✗ Oil prices vary (with the market)
  • ✗ Need cleaning more than gas boilers
  • ✗ Require oil deliveries



What Is the Best Oil Boiler?

Brand

Product Name

Type

Mounting

Efficiency Rating

Average Price

Grant
Vortex Boiler House 21-26
Conventional
Floor-standing
A
£2,000.00
Grant
Vortex Eco Utility 15-21
Conventional
Floor-standing
A
£1,100.00
Grant
Vortex Eco Wall Hung Internal 16-21 System
System
Wall-mounted
A
£1,500.00
Worcester Bosch
Greenstar Danesmoor External System 25-32 ErP
System
Floor-standing
A
£2,400.00
Worcester Bosch
Greenstar Heatslave II External 12-18 ErP
Combi
Floor-standing
A
£2,300.00


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The Best Boiler Brands in 2018

The best boiler brands are generally well-known and long-standing manufacturers. Companies such as Viessmann, Worcester Bosch and Vaillant are trusted names within the industry. Choosing any of these companies will allow you to feel safe in the knowledge that you are receiving a high quality product. The other factor you should also consider is a boiler's efficiency rating and it's worth aiming for an A-rated system, which will ultimately help to reduce your energy bills.

To find the UK's best boiler brands, we compared independent research from the Which? experts with real customer reviews on Trustpilot, and spoke to engineers up and down the country to track down the most reliable boiler manufacturers.

The best boiler brands in the UK are:

  • Grant
  • Ideal
  • Vaillant
  • Viessmann
  • Worcester Bosch

The table below compares the key features of the best boiler brands based on our own research:

Brand
Boiler Types
Warranty
Build Quality
Reliability
Ease of Use
Trustpilot Score
Grant
Combi, Conventional, System
2 to 5 years
4/5
4/5
4/5
9.6/10*
Ideal
Combi, Conventional, System
2 to 5 years
3/5
3/5
4/5
5.7/10*
Vaillant
Combi, Conventional, System
2 to 5 years
4/5
3/5
4/5
8.6/10*
Viessmann
Combi, Conventional, System
2 to 5 years
5/5
5/5
5/5
8.3/10*
Worcester Bosch
Combi, Conventional, System
2 to 6 years
4/5
5/5
4/5
9.2/10*

*Correct at time of writing on 15th November 2018



;

Grant: Best for oil boilers

grant boiler

Overall Rating:

Grant has been manufacturing boilers for over 35 years. The Wiltshire-based company is particularly focused on tackling issues such as high energy prices and CO2 emissions. Multiple Grant boilers were named winners in the Which? magazine Best Boiler Buy category in 2017.

Grant is best known for its oil boilers, although it is working towards creating more eco-friendly heating systems. The company manufactures 2 core types of oil-fired boilers: the Vortex Pro and the Vortex Eco. The Vortex Pro is available as an internal or external unit and comes with many heat outputs to fit all sizes of home. The Vortex Eco is a system boiler, available in different heat outputs and options to attach to the wall or as a free-stand. Grant boilers range in price from £1,180 to £2,380 depending on their size and sophistication.

Grant scores well on build quality, reliability and customer care, and its customers are likely to recommend Grant to friends or family members. The company offers a 5-year guarantee for its Vortex Condensing Boilers.

  • Pros
  • ✓ Well-built eco boilers
  • ✓ Very reliable products
  • ✓ Great customer service
  • Cons
  • ✗ Not the cheapest



Ideal: Best for customer care

ideal boiler

Overall Rating:

Hull-based boiler brand Ideal has been around for more than 100 years, and today offers a range of combi, system and conventional boilers.

Popular models across the Ideal range include Logic and Logic+ combi, system and conventional boilers, Ideal Mexico boilers and Ideal Imax boilers. Its boilers range in price from £590 to £2,200 depending on the model.

Ideal performs moderately well across a range of measures including build quality and customer care. Many customers complain that Ideal boilers are unreliable however, having a tendency to become faulty within a year after installation.

All Ideal boilers with a standard warranty come with a free two year parts and labour repair service. It offers a free 5-year parts and labour repair service for boilers with an Ideal+ warranty offer.

  • Pros
  • ✓ Good availability of spare parts
  • ✓ Quality boilers
  • ✓ 4 out of 5 engineers recommend Ideal
  • Cons
  • ✗ Cheaper models are less reliable



Vaillant: Leader for over 135 years

vaillant boiler

Overall Rating:

Vaillant is a German company which has been a key player in the heating market for over 135 years, and now sells its products in more than 80 countries.

It offers upwards of 30 boilers, in combi, conventional and system models. Its boiler range provides options for all sizes of homes and power levels, from the basic EcoTec Pro to the more powerful EcoTec Plus. Its boilers range in price from £670 to £3,000.

In general, Valliant customers are happy with its range of boilers. Many claim that Vaillant boilers are particularly easy to use and are made to a good standard. Whilst some people have had issues with their boiler, they report that problems have been dealt with quickly by the company’s team of 200 specialist engineers. Vaillant offer a minimum 2-year parts and labour warranty, which can be extended up to 10 years.

  • Pros
  • ✓ Most engineers rate Vaillant
  • ✓ Some of easiest boilers to service
  • ✓ Top-notch quality
  • Cons
  • ✗ Starting price is higher than some rivals



Viessmann: UK's most popular boilers

viessmann boiler

Overall Rating:

Viessmann has been manufacturing boilers since 1917 and has expanded on an international scale, selling boilers in 11 countries around the world. Multiple Viessmann boilers were named winners in the Which? magazine Best Boiler Buy category in 2017.

Viessmann produces a range of combi, conventional and system boilers. The Vitodens range of condensing combi boilers prove popular and are available with features such as an outdoor temperature sensor, which allows the boiler to adjust the temperature of your home automatically according to changes in the weather. Viessmann boilers range in price from £740 to £1,500 depending on their size and features.

Viessmann receives very good feedback from its customers, with many recommending a Viessmann boiler to friends and family members. It scores particularly highly for its build quality and reliability, with very few customers encountering an issue with their boiler. The company offers a 2-year parts and labour warranty.

  • Pros
  • ✓ One of most reliable boilers
  • ✓ Recommended by engineers
  • ✓ Excellent build quality
  • Cons
  • ✗ Low spare part availability
  • ✗ Not always easy to service boilers



Worcester Bosch: Most recommended by engineers

worcester bosch boiler

Overall Rating:

Worcester Bosch has been manufacturing boilers since 1962. The company is part of the larger Bosch Group and has over 2,000 employees based in Worcester and Derbyshire. Multiple Worcester Bosch boilers were named winners in the Which? magazine Best Boiler Buy category in 2017.

Its range of domestic combi boilers include the Greenstar Junior and Greenstar Si series. Its Greenstar Ri series is a popular conventional boiler for more traditional homes that use a cold water tank and hot water cylinder. It also produce system boilers such as the Greenstar 12i, 24i and 30CDi. Worcester Bosch's boilers range in price from £570 to £6,188 and are supplied by certified Worcester Bosch installers.

Worcester Bosch has a strong reputation with very few negative reviews. It scores very highly for reliability, although some customers have reported that the controls on their boilers can sometimes be difficult to use. The company offers a variety of different warranties and guaranties including a 10-year guarantee on the heat exchangers in the boilers.

  • Pros
  • ✓ Boilers for any price point
  • ✓ Some of the most reliable boilers
  • ✓ 5 out of 5 engineers recommend
  • ✓ Top boiler quality
  • ✓ Spare parts on demand
  • Cons
  • ✗ Some models are expensive
  • ✗ Some faults are not easy fixes



Other Boiler Brands

Alpha

Energy-saving boilers

UK company, Alpha, has been manufacturing boilers for the last 50 years. In addition to boilers, Alpha also focuses on developing energy-saving products so that customers can switch to low carbon technologies like solar panels, more easily.

Its range of domestic boilers include combi, conventional and system to suit a variety of homes. Its boilers range in price from £700 to £2,200 depending on their size and sophistication. The company offers up to a 7-year warranty on its boilers depending on the accreditation of the installer.

Alpha performs moderately well in terms of reliability, but scores poorly on the quality of their boilers. It is not known to be hugely popular with engineers, although customer satisfaction is reasonably good.


Baxi

Making boilers since 1866

Baxi has been in business since 1866. The company is now part of BDR Thermea, one of the largest European boiler manufacturers who also own Potterton and Main.

Its range of domestic boilers include combi, conventional and system varieties. Popular in Baxi’s range are the Baxi Ecoblue, Baxi Platinum HE A combi boilers, Baxi Duo-tec GA combi boilers and Neta-tec GA combi-boilers. There is also the the Baxi Solo heat-only boiler range, the Baxi Bermuda back boiler range, and the Baxi Megaflo compact system GA boiler range.

Its boilers tend to be cheaper than other brands, varying in price from £700 to £1,170 depending on their size and sophistication. Most come with a 2-year warranty.


Glow-worm

Quality boilers with a 5-year warranty

British company, Glow-worm, has been around for more than 75 years, originally begun producing boilers in 1934 at the Derwent Foundry in Derbyshire.

Popular models include the Glow-worm Flexicom cxi boilers, Glow-worm Ultracom2 cxi boilers, and Glow-worm Betacom2 and Easicom boilers. It also offers open-vent Ultracom hxi and Flexicom hx boilers, the Ultracom2 and Flexicom sx system boilers and Ultrapower sxi system store boilers. Glow-worm's boilers range in price from £590 to £2,200 depending on their specification.

Whilst Glow-worm does provide a sound 5-year warranty for its Ultimate range of boilers, it does receive criticism for the build quality and reliability of its boilers.


Potterton

A decent range of boilers

Potterton has been around for more than 150 years. This British company claims to have manufactured over 5 million boilers in that time, and are still going strong today.

Popular Potterton boiler models across several combi boiler ranges, including Potterton Gold and Titanium combi boilers, Potterton Promax, Performa and Potterton Heatmax combi boilers. Its conventional boilers include the Potterton Promax boiler range as well as Promax and Performa system boilers. Its boilers range in price from £610 to £1,000 depending on their size and sophistication.

Potterton is commended for their customer care, although its boilers tend to be more unreliable than other brands. Most Potterton boilers come with a 2-year warranty.


Ferroli

Some of the cheapest boilers

Italian brand Ferroli has over 50 years’ experience making boilers throughout Europe, and has a vast selection of combi and system boilers.

Ferroli boilers cost between £500 and £750, and are some of the cheapest boilers around. The only drawback is some engineers say they are not as reliable as some other brands, and can be complicated to fix.


Ariston

Very reliable boilers

Ariston has been providing the UK with reliable boilers for nearly 50 years now. The company offers combi and system boilers to over 150 countries, with prices ranging from £550 to £1,000.

Ariston makes some of most reliable and affordable boilers, as well as decent customer care and easy fixes to the most common problems, but its name doesn’t always come up when engineers give their most recommended boiler brands.


Intergas

Easy to service boilers

Netherlands brand Intergas has been manufacturing boilers for over 40 years, and provides combi, conventional and system boilers to suit homes of any size.

Intergas boilers cost between £650 and £1,100: they are reliable and easy to service, but repair parts can take time to arrive.


Vokera

Spare parts come quickly

Vokera makes gas condensing boilers to homes throughout the UK, and prices range from £650 to £1,200.

Vokera is a popular boiler brand, and although some engineers complained of complex faults, spare parts tend to be readily available if you ever need them.


Which boilers do engineers recommend?

Here, Francis, a Gas Safe registered boiler engineer, gives his opinion on what he believes are the best boiler brands and why he particularly likes Viessmann boilers:

 



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Best Boiler for Your House

The best boiler for your house will depend on the size of your house and your heating/hot water needs. The best boiler for a 1 bedroom flat will not necessarily be the same as the best boiler for a 3 bedroom, detached house. Below we have compared the best boilers for small, medium and large properties.


best boiler for a one or two bedroom house

Best Boiler for a One or Two Bedroom House

If you have a smaller 1-2 bedroom house (or flat), with only one bathroom, then you will be best off with a small combi or system boiler installation. A small property will require a boiler of around 24kW to 27kW. Here are our recommendations for the best boilers for a 1 or 2 bedroom house in 2018.

Brand
Product Name
Type
Maximum Output (kW)
ErP Efficiency Rating
Average Price
Grant
Vortex Eco External System 21-26
System
26kW
A
£1,700.00
Ideal
Esprit Eco 24
Combi
24kW
A
£1,080.00
Vaillant
ecoTEC pro 24
Combi
24kW
A
£860.00
Viessmann
Vitodens 100-W Combi 26kW
Combi
26kW
A
£920.00
Worcester Bosch
Greenstar 24i System ErP
System
24kW
A
£990.00



best boiler for a three bedroom house

Best Boiler for a Three Bedroom House

Average sized 3 bedroom houses, perhaps with one bathroom and an en suite, can benefit from a range of boilers. A more powerful combi boiler (28kW-34 kW) should suit your needs and is the easiest and least space demanding option. A new, energy efficient conventional boiler (18kW-24kW), with a water tank, could also be an option. It is best to talk to a qualified installer to receive the best advice for your situation.

These are our recommendations of the best boilers for an average 3 bedroom house in 2018.

Brand
Product Name
Type
Maximum Output (kW)
ErP Efficiency Rating
Average Price
Grant
Vortex Boiler House 21-26
Conventional
21kW
A
£2,020.00
Ideal
Mexico HE 24
Conventional
24kW
A
£1,500.00
Vaillant
ecoTEC exclusive 838
Combi
32kW
A
£1,480.00
Viessmann
Vitodens 200-W Combi 30kW Weather comp
Combi
30kW
A
£1,370.00
Worcester Bosch
Greenstar 30Si Compact ErP
Combi
30kW
A
£1,250.00



best boiler for a four bedroom house

Best Boiler for a Four Bedroom House

Large, four bedroom and above houses, will have higher heating and water demands and will therefore require a more powerful boiler. Typically experts do not recommend combi boilers for larger houses as they do not cope as well with multiple showers and appliances using hot water simultaneously.

Speak to an expert installer to find out what type of boiler would be best for your property. These are our recommendations for the best boilers for large, 4 bedroom houses in 2018.

Brand
Product Name
Type
Maximum Output (kW)
ErP Efficiency Rating
Average Price
Grant
VortexBlue Internal Sealed System 26
Conventional
36kW
A
£2,615.00


Ideal
Mexico HE 36
Conventional
36kW
A
£2,615.00
Vaillant
ecoTEC plus 438
Conventional
38kW
A
£1,400.00
Viessmann
Vitodens 100-W Open vent 35kW WB1B
Conventional
35kW
A
£1,365.00
Worcester Bosch
Greenstar FS 30CDi Regular ErP
Conventional
30kW
A
£1,470.00


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FAQs

What is the best boiler?

The best boiler for your home depends on the type and size of the boiler you need. Boilers by brands such as Worcester Bosch, Viessmann, and Vaillant are considered the best on the market. The best boilers are:

  • Best boiler for a one/two bedroom house: Viessmann Vitodens 100-W Combi 26kW
  • Best boiler for a three bedroom house: Worcester Bosch Greenstar 30Si Compact ErP
  • Best boiler for a four bedroom house: Vaillant ecoTEC plus 438

What is the best combi boiler?

The Worcester Bosch Greenstar Highflow 44 0 CDi ErP is the best combi boiler for most homes, and at £1,900 it is a mid-range price for a free-standing, energy efficient boiler.

Which boiler brand is the best?

Based on feedback from homeowners and boiler engineers, the best boiler brand in the UK is Worcester Bosch. Worcester Bosch makes over 40 different boilers, which have been praised for their reliability and performance. Other high quality boiler brands include Viessmann, Vaillant, Grant and Ideal.

How often do you need a new boiler?

A boiler should last up to 15 years before it needs replacing. If your boiler is approaching this age, you should think about investing in a new one. To ensure your boiler lasts for as long as possible, you should have it serviced every year. This will make sure it’s working properly and safely, and will help to avoid any damage or faults.

How much does it cost to replace a boiler?

It costs anywhere from £500 to over £4,000 to buy a replacement boiler, with installation costing around £500 to £1,500 on top. Exactly how much you’ll pay will depend on what type of boiler you get and where you have it installed in your home. To find out more about the cost of a replacement boiler, visit our guide to boiler prices.

What's the easiest way of comparing boiler quotes?

Our expert boiler reviews use independent research from the most trusted sources: Which? reports, real-life user reviews on Trustpilot, and our own surveys of engineers and boiler owners should help you be ready to compare prices from the UK's leading boiler brands.

Here at Eco Experts, we are helping our readers get free quotes in three simple steps:

  1. Fill in our form to tell us what you need
  2. Get matched, and talk directly with the best boiler suppliers for you
  3. Compare the quotes, and see how much time and money you save

Just click below to get started.

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