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What is a Regular (Conventional) Boiler? Pros, Cons & Costs

Becky Mckay
By: Becky Mckay
Updated: 6th July 2022

Regular Boiler

A regular boiler (also known as a conventional or heat only boiler) is the traditional heating system found in the UK. If you have a large tank of water in the loft and a hot water cylinder in an airing cupboard, you have a regular boiler.

Here we answer all your questions about regular boilers, including the all important question: how much does a regular boiler cost?

What is a regular boiler?

Regular boilers are one of the oldest types of boilers around. They are also known as ‘traditional’ or ‘conventional’ boilers. In the industry, they are known as ‘heat only’ boilers, because they will produce hot water for central heating, but not for domestic use, i.e. taps, baths or showers.

A regular boiler is fed cold water from a water storage cistern (commonly called a ‘tank’) which is stored in the attic. It also requires a hot water storage cylinder to be able to provide hot water for daily use.

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How does a regular boiler work?

To provide heating, cold water from the cistern in the loft feeds down to the boiler. The cistern is usually as high above the boiler as possible to help improve the water flow in your system.

Regular Gas Boiler

When you fire up the boiler (either by turning on the hot tap or switching on the heating), that cold water is then warmed up by a heat exchanger. The heated water is then pumped to a hot water storage cylinder (which is usually in an airing cupboard) where it is stored and circulated until you need it. From there, valves will direct the hot water to either your heating or your taps/outlets.


Regular boilers are the most traditional type of heating system. Whilst a system or a combi boiler might appear to be more convenient, regular boilers are still a viable option for many homes.

Difference between regular and system boilers

A regular boiler and a system boiler are very similar in that both rely on a hot water storage cylinder to keep a store of hot water ready for your taps. The key difference, however, is that a regular boiler is supplied with cold water via a cistern in the attic, while a system boiler takes its water supply directly from the mains. This means that you don’t need to have a cold water cistern in your attic.

Difference between regular and combi boilers

A combi boiler is a more modern system, and the most commonly installed type of boiler in the UK today. A combi boiler is an all-in-one unit that does not need a cistern in the attic or a hot water cylinder. The combi takes its cold water supply directly from the mains and heats it on demand. This means that there is no large store of hot water, so they are generally only recommended for small to medium-sized homes which use less hot water.

Is a regular boiler right for your home?

There are many things to consider when choosing which type of boiler is right for your home. It’s good to weigh up the pros and cons so that you get the most suitable set-up for your needs.

Pros of regular boilers

Can meet high demand for heating and hot water

If you live in a home with several bathrooms or have an especially high demand for heating and hot water, a regular boiler is a great choice. With its large storage capacity for hot water, it means multiple taps and outlets can be used simultaneously.

Simple to replace an older system

If your home already has a regular boiler system, it will prove less disruptive and costly to simply replace it with a newer version.

They've become more efficient

Regular boilers that are non-condesing should be replaced with a new condensing one, as it will make your energy consumption much more efficient and help to reduce the cost of your bills. Some regular boilers can now reach efficiencies of as high as 97%.

Fit an immersion heater as a backup

To ensure that you won't go without hot water if your boiler breaks down, you can fit an electric immersion heater to the hot water cylinder for an alternative way to heat the water.

Solar compatible

Many regular boilers can work with solar thermal panels to generate warm water using energy from the sun. You will just need to ensure that the cylinder and model you chose is compatible.

Cons of regular boilers

Take up a lot of room

Since you need space for a cold water cistern and hot water storage cylinder, regular boilers aren't really suitable for homes with limited space.

Hot water isn't instant

Due to the hot water being stored in the cylinder, once it's used up you will have to wait for it to refill before you can use hot water again. It's important to think about how much water is used around your home when choosing a water cylinder as they come in different capacities.

Expensive installation

As they require separate parts installed throughout the house, a new regular boiler installation can be a lengthy and costly process.

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Which are the best regular boilers?

Regular boilers are available in either gas or oil from a range of manufacturers. Rather than list every range available, we've listed the ones that consistently receive excellent reviews for customer satisfaction and engineer recommendations.
Baxi 430 Heat

Baxi 400 Heat

  • Up to 5 year parts and labour warranty
  • Fits inside a standard kitchen cupboard
  • Works extremely quietly
  • Rear flue option for an even neater finish
  • Compatible with market-leading Megaflo Eco cylinder
  • Available in 12, 15, 18, 24 or 30 kW

Ideal Logic Max Heat H30

Ideal Logic Max Heat

  • Up to 10 year parts & labour warranty
  • Made in the UK
  • High quality brass system filter
  • Compact cupboard fit, discrete install
  • Easy to install (low lift weight) & easy to use
  • Available in 12, 15, 18, 24 or 30 kW

Vaillant ecoTEC Plus

Vaillant ecoTEC plus Regular

  • High performance, control and efficiency
  • Compact enough to fit in a kitchen cupboard
  • Hand-built in award-winning Derbyshire manufacturing plant
  • A wide range of heating control options including smartphone app
  • 5-year guarantee as standard with 7 to 10 years available
  • Available in 12, 15, 18, 24, 30 or 35 kW

Viessmann Vitodens 100-W

Viessmann Vitodens 100W Open Vent

  • Compact dimensions to fit in standard kitchen cupboards
  • LPG conversion available
  • Energy efficiency class: A
  • Standard efficiency up to 97% through stainless steel Inox-Radial heat exchanger
  • Weather compensation option
  • Large user display
  • 5 year comprehensive warranty as standard (extended warranty option up to 10 years)
  • Available in 13, 16, 19, 26 or 35 kW

Worcester Bosch Greenstar Ri

Worcester Bosch Greenstar Ri

  • Small enough to be installed in a standard kitchen cupboard
  • Up to a 10 year guarantee
  • Simple boiler controls
  • Suitable for homes where the heating system includes a hot water storage cylinder
  • Frost protection
  • Can be used with Greenskies solar panels

Comparing regular boiler reviews

Finding the best boiler for your home involves taking the time to compare different models. When comparing regular boilers, here are some things to look for:

Output rating

This is the power of the boiler and is measured in kilowatts (kW). Regular boilers have a central heating output rating which gives an idea of how many radiators the unit will be capable of heating up. As general guidance, allow for between 1.5kW and 2kW per radiator.


Boilers convert fuel into usable energy and how much of the fuel ends up being converted is reflected in the efficiency rating. The higher the rating, the less fuel is wasted.


All boilers come with a warranty which will see that you're covered by the manufacturer should it develop an issue after the installation. What the warranty covers, and how long for, will vary from boiler to boiler.

Potential cost

Regular boiler prices range from around £500 to £2,000 without the cylinder, and before installation. Depending on how much you're looking to spend there are options to suit all budgets.

Heating controls

Having greater control of your heating will allow you to keep energy usage to a minimum. Many modern boilers can now be controlled from a smartphone or tablet.

Heating engineer reviews

When it comes to boilers, heating engineers are the experts. Reading their reviews, and getting opinions from fully-qualified heating engineers will give you valuable insight into the boiler you're considering.

Customer reviews

Taking the time to read through reviews left by homeowners can give you an idea if others have had any problems over the years. Take care not to focus your whole decision on this though, as no two properties, or personal usage, are exactly alike.

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Boiler installation costs

Boiler replacement costs will vary depending on the work involved and the type of boiler being installed. The cost of installation will also need to be considered, as the rates charged by engineers will differ.

Regular gas boiler prices can range from as little as £600 right up in the region of £3,000 depending on the make and model. You will also need to consider the cost of replacing the hot water cylinder.

Various factors can also influence how much an installation will cost, some of these include:

  • The complexity of the installation (a like-for-like replacement will cost less than a complete change of heating system)
  • Accessibility
  • Whether the boiler is moving to a new location
  • Where you live (boiler installations tend to be more expensive in London, for example)

What size regular boiler do you need?

Boiler Size
The size of the regular boiler is one of the most important factors to consider. By size, we don't mean the physical dimensions of the boiler, we mean how powerful the boiler is. This is known as the output rating and is measured in kilowatts (kW).

Effectively, the higher the output rating, the more powerful the boiler. Having said this, it isn't a good idea to simply install the boiler with the highest output rating. An output rating that's too high for your home could cause your energy bills to rise. If it's too low, it will struggle to meet demand.

The recommended output ratings in the table below are intended as a guide. To get a more accurate idea, you should get a quote from a Gas Safe registered engineer.

Bathrooms Radiators Recommended Output
1 10 10-18 kW
2-3 15 18-26 kW
3+ 20 27-40 kW

What size hot water cylinder do you need?

If you have a large home, with more than 1 bathroom you should choose a hot water cylinder with a larger capacity. This will ensure it meets the demands of your home. If it’s a particularly large property, however, you may even consider multiple cylinders.

The table below shows a guideline for the capacity you should consider depending on the size of your property.

Bedrooms Bathrooms Cylinder Capacity (litres)
1 1 120 – 150
2 1 180
3 2 210
4 2 250 – 300
4+ 2+ 300+

Finding the best regular boiler installer

A new regular boiler is a big investment, so you'll want the installation to be carried out to the highest standard by a competent installer for the best possible price. By law all gas-fired boilers must be installed by a Gas Safe registered engineer (an OFTEC technician is needed for the installation of oil boilers).

Rather than accepting the first quote you receive, we highly recommend comparing at least 3 quotes from different companies. Taking the time to compare quotes will help you to find the most competent installer offering the most competitive price.

At Boiler Guide, we have a network of over 5,000 Gas Safe registered boiler installers. Complete our online form today to get free quotes from up to 3 local heating companies.

Becky Mckay

About the author

Becky Mckay

Becky is one of our home heating and renewable energy experts and has a wealth of experience writing about the world of heating.

approved by engineer This article has been checked and approved by a Gas Safe registered engineer.

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