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Last updated: 13 March 2024

What is a Conventional Boiler? Pros, Cons & Prices Included

Conventional boiler

A conventional boiler —also known as a regular boiler or a heat-only boiler— is a traditional heating system suitable mainly for large houses. These units are among the oldest types of boilers around; however, it doesn’t mean they are outdated models. In fact, all boiler brands keep manufacturing highly efficient regular boilers compatible with modern technologies.

In this article, you will learn about conventional boilers’ features, pros, cons, and also prices. We have also included our selection of the best regular boilers by the top brands available in the UK.

Conventional Boilers’ Key Features

Conventional boilers produce hot water for central heating, but not for your taps or showers. This is why they are also called heat-only boilers. To do the full job (providing hot water for your central heating system and also for domestic use), they need a large tank of water in the loft and a hot water storage cylinder.

As you can see, a regular boiler will take some space around your home. However, having a hot water storage cylinder is precisely the feature that allows conventional boilers to provide hot water to multiple hot water outlets at the same time. The bigger the cylinder, the higher the domestic hot water demand your conventional boiler can meet.

This might make you wonder what size of hot water cylinder your house needs. Another option is installing multiple cylinders. You can look at the table below to get an estimate.

Conventional Boilers Cylinders For Different Types of Houses

Bedrooms

Bathrooms

Cylinder Capacity (litres)

1

1

120 – 150

2

1

180

3

2

210

4

2

250 – 300

4+

2+

300+

At GreenMatch, we are committed to helping homeowners across the UK in their efforts to make their houses greener. When it comes to domestic heating, low-carbon systems such as solar panels in the UK, heat pumps, or biomass boilers are the most sustainable alternatives to gas boilers. However, we know that these are expensive alternatives.

If you want to replace your old conventional boiler but are not ready yet to switch to low-carbon systems because of either technical or financing reasons, then consider installing a new one that is highly efficient. As a new boiler will burn less fuel to achieve the same result, you will reduce your home’s carbon footprint.

Our experts can send you up to 4 offers for boilers from suppliers that operate near you. Comparing them will allow you to lock in the best deal. Our service is free, and you are not obliged to accept any quote you receive.

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How Does a Conventional Boiler Work?

To provide heating, cold water from the tank in the loft feeds down to the boiler. This water deposit is typically positioned as high above the boiler as possible to improve the water flow. When the boiler fires up, a heat exchanger warms up that cold water before it is pumped to the radiators or the hot water cylinder. 

Once in the cylinder, the water will be directed to the taps/showers as needed. You can use multiple hot water outlets simultaneously without experiencing a decrease in the hot water flow or its temperature. However, if you use too much hot water, you may need to wait until your conventional boiler heats up more water to refill the cylinder.

Conventional boiler diagram

You are already familiar with a regular boiler’s main components, how they work, and how much space they will take. The diagram below summarises it.

Conventional Boiler Diagram

Pros and Cons of Conventional Boilers

Pros of Conventional Boilers
  • Can meet high demands for heating and hot water. Due to its large storage capacity, a regular boiler is a great choice if you live in a home with several bathrooms and a high demand for heating and hot water.
  • Simple to replace for a new regular boiler. You won’t need to adjust the pipework or remove components such as the cold water tank.
  • New models are highly efficient. Condensing technology has improved conventional boilers’ efficiency (up to 97% for some models). A condensing regular boiler can help you reduce your heating bills and also your home’s energy consumption.
  • Solar compatible. Many regular boilers are compatible with solar thermal panels. You can improve the hot water generation process by making it more eco-friendly.
Cons of Regular Boilers
  • Take up a lot of room. Conventional boilers are not suitable for homes with limited space since they need extra components in addition to the main unit (e.g. cold water tanks and hot water storage cylinders).
  • Hot water isnt instant. Even though you can get hot water from multiple taps or showers at the same time, you will have to wait until the cylinder refills if you use all the hot water at once. Houses with larger demands for hot water require bigger or multiple cylinders.
  • Expensive installation. A new regular boiler installation can be costly, requiring separate parts to be installed throughout the house. However, a like-for-like regular boiler replacement is likely cheaper since you can use the same pipework, water and gas installations.

Combi vs conventional boiler

Combi boilers are the most commonly installed type of boiler in the UK. As they are more modern systems than regular boilers, you might be considering one of those for your house. Nevertheless, it is better if you compare them and analyse whether they suit your property.

A combi boiler is an all-in-one unit. It does not need extra components such as feed tanks or hot water cylinders. This is certainly good news if your home has limited space available. 

They also provide hot water on demand, meaning you won’t have to wait for the cylinder to refill if you use too much hot water. The downside is that since combi boilers don’t have a storage cylinder, the hot water flow may weaken if multiple outlets are used simultaneously. For this reason, they are recommended for small to medium-sized homes with 1 bathroom.

System boiler vs conventional boiler

System boilers are also a viable option. They are considered modern, smaller versions of conventional boilers mainly because they both need storage cylinders to supply hot water to your taps, showers and baths. The main difference is that system boilers take cold water from the mains rather than from a tank in the loft. This means that you will save space.

But space is not the only thing you would save if you decide to replace your old boiler with a new combi, system or regular boiler. For instance, in a gas-heated detached home in England, Scotland or Wales, you could save up to £580 per year on your energy bills by replacing a poorly efficient boiler with a highly-efficient condensing one.

Considering that the average household currently pays £1,971 per year on energy bills, £580 represents approximately your domestic energy expenses for more than three months. To start saving, just click on the button below, and we will send you up to 3 free, non-binding quotes.

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Best Conventional Boiler

Below, we’ve listed what are, in our opinion, the best conventional boilers available in the UK. We included 1 model from each of the top 5 boiler brands in the country.

Best Worcester Bosch regular boiler

Worcester Bosch Greenstar 8000 Life

Worcester Bosch Greenstar 8000 Life

  • Available central heating output ratings: 30kW, 35kW, 40kW, 45kW, and 50kW
  • Suitable for: Homes with up to 20 radiators to larger homes with over 20 radiators and high demand for heating.
  • Efficiency: 94% efficiency and ErP A-rated for heat.
  • Warranty: 5 years as standard. It can be extended to 12 years when installed by a Worcester Bosch Accredited Installer.
  • Estimated price (Exc. installation): £1,255 – £2,300.

Best Vaillant regular boiler

Vaillant ecoTEC plus

Vaillant ecoTEC plus

  • Available central heating output ratings: 30kW, 35kW, 40kW, 45kW, and 50kW
  • Suitable for: Homes with up to 20 radiators to larger homes with over 20 radiators and high demand for heating.
  • Efficiency: 94% efficiency and ErP A-rated for heat.
  • Warranty: 5 years as standard. It can be extended to 12 years when installed by a Worcester Bosch Accredited Installer.
  • Estimated price (Exc. installation): £1,255 – £2,300.

Best Baxi regular boiler

Baxi 800 Heat

Baxi 800 Heat

  • Available central heating output ratings: 16kW, 25kW, 30kW
  • Suitable for: Homes with up to 15 radiators to properties with around 20 radiators.
  • Efficiency: 93% and ErP A-rated for heat
  • Warranty: 10-year parts and labour warranty
  • Estimated price (Exc. installation): £787 – £944

Best Ideal regular boiler

Ideal Logic Max Heat

Ideal Logic Max Heat

  • Available central heating output ratings: 12kW, 15kW, 18kW, 24.2kW, and 30.3kW
  • Suitable for: Homes with around 10 radiators to houses with approximately 20 radiators
  • Efficiency: 93% (94% the 24.2kW model) and ErP A-rated for heat
  • Warranty: 10-year parts and labour warranty
  • Estimated price (Exc. installation): £885 – £1,117

Best Viessmann regular boiler

Vitodens 100-W Heat Only

Vitodens 100-W Heat Only

  • Available central heating output ratings: 11kW, 16kW, 19kW, 25kW, and 32kW
  • Suitable for: Its wide range of available central heating output ratings makes this boiler suitable to meet the demands of almost any type of house
  • Efficiency: 93% and ErP A-rated for heat
  • Warranty: 5 years as standard. It can be extended to 12 years if installed by a Viessmann Trained Installer.
  • Estimated price: Currently, some Viessmann partners’ web pages show Vitodens 100-W Heat Only prices ranging from £1,099 to £1,607 (Inc. VAT). However, it is subject to availability. They also mention that the Recommended Retail Price is much higher (£2,199.60 to £3,214.80)

Conventional Boiler Prices

Conventional boiler prices range from around £500 to £2,000. This excludes the hot water storage cylinder and installation

Regardless of type, several factors can affect the cost of a new boiler. For instance, the brand, model, output rating (power), special features, accessories, and warranty length can impact the final price.

Additionally, you must consider installation costs. This will vary depending on the complexity of the installation, the installer’s rates and the region or city you live in. For example, boiler installations tend to be more expensive in big cities than in rural areas.

Cost to replace a conventional boiler

You can replace your conventional boiler with a new one or with any other type of boiler. However, a like-for-like boiler replacement will cost less than a complete change of heating system.

It is worth noting that, at approximately £3,500, replacing a conventional boiler with a combi is probably the most complex and expensive boiler swap. The installer will need to reconfigure the pipework setup and remove the hot water storage cylinder and the feed water tank.

In this regard, as installers’ rates vary from heating company to heating company, comparing offers from multiple engineers in your area is a practical way to lower costs and avoid being overcharged. The only downside is that looking for local heating engineers takes lots of time and effort. But this is something we can help you with.

Click on the button below, and we will send you up to 4 offers from local Gas Safe registered engineers. You will save a lot of time and will get attractive deals to choose from. Our service is free of charge, and you don’t have to accept any quote you receive.

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FAQ

Luis Antonio Gómez Pérez

Luis Antonio is a seasoned Content Writer with international journalism experience. His writing style, enriched by a Master’s in Journalism, contributes informative content to GreenMatch on topics including low-carbon heating systems.

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