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1,263 reviews

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1,263 reviews

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

Regular Boiler
A regular boiler (also known as a conventional or heat only boiler) is found in a traditional UK heating system. 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 the oldest type of boiler around. Which is why they are also known as traditional or conventional boilers. Another name for them is heat only boilers, because they will produce hot water for a central heating system, but not domestic use, i.e. taps, baths or showers.

A regular boiler is fed cold water from a large tank of water which is stored in the attic and also requires a hot water storage cylinder to be able to provide hot water for daily use.

In the past, regular boilers would be installed into your home as standard, but now there are more popular options such as a system or a combi boiler. However, in some homes, a regular boiler is still an effective heating system.
Regular Gas Boiler

How does a regular boiler work?

A regular boiler needs a large tank of cold water (which is usually installed in an attic) to supply it with cold water from the mains. To provide heating, cold water from the tank in the loft feeds down to the boiler with a helping hand from gravity. The tank needs to be as high above the boiler as possible to increase the pressure of the water in your system.

When the boiler ignites, a heat exchanger warms up the water. The heated water is then pumped to a hot water storage cylinder (which is usually in an airing cupboard) where it is stored until you turn on your heating, a shower or a tap.

Regular boilers are the most traditional type of heating system and many homes may find either a system or a combi boiler 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 radiators and taps. The key difference, however, is that while a regular boiler is supplied with cold water via a feed tank in the attic, a system boiler takes its water supply directly from the mains. This means that you don’t need to have a large tank of cold water in your attic.

Difference between regular and combi boilers

A combi or combination 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 which does not need a feed tank in the attic or a hot water cylinder in an airing cupboard. The combi takes its cold water supply directly from the mains and heats it on demand. This means that there is no store of hot water, however, so they are generally only recommended for small to medium sized homes.

Is a regular boiler right for your home?

While lots of homeowners choose to replace an old regular boiler with either a system or a combi boiler, there are some situations where installing a modern, efficient regular boiler is the best solution.

Here are some of the main pros and cons of installing and living with a regular boiler.

Pros of regular boilers

Can meet a high demand for heating and hot water

If you live in a large home with several bathrooms or have an especially high demand for heating and hot water, a regular boiler is the ideal choice. By storing hot water, ready to be sent to taps and radiators for use when required, hot water can be served to several places simultaneously.

Simple to replace an older system

If you live in an older home with a traditional heating system, then installing a new regular boiler will minimise the disruption and cost involved.

They've become more efficient

Regular boilers that are a few years old should probably be replaced with a new one as it could make your home 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 tank 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 that then feeds into the central heating system.

Cons of regular boilers

Take up a lot of room

As you need space for a hot water tank and a cylinder, regular boilers require lots of space which means that they aren't really suitable in homes where space is limited.

Hot water isn't instant

The hot water is stored, which means that once it's used up, you'll need to wait for more water to heat up. It's important to think about how much water is used around your home when choosing a water cylinder.

Heat loss

Another downside to the water being stored is that there is potential for heat loss. To help prevent this, ensure that your hot water tank is well insulated.

Expensive installation

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

Swapping a regular boiler for a combi or system

Converting from a regular boiler to a system or combi boiler will require a more complex installation and will therefore be more expensive, but if you are carrying out an extensive refurbishment on your home anyway, it may be the perfect time to update the heating system.

Here are some situations when a combi or system boiler might be the best choice.

  • If you have a small home and are looking to free up some space, then swapping your regular boiler for a combi boiler is a great idea as you will be able to get rid of the tank in the attic and the cylinder in your airing cupboard. You will have hot water on demand which is often much more convenient and cheaper than having to heat a store of hot water.

  • If you have a larger home, e.g. a 3-4 bedroom home with multiple bathrooms, then swapping your regular boiler for a system boiler could be the best choice. You will be able to get rid of the tank in the attic but will still have the higher volume of hot water.

  • If you live in an area with strong mains water pressure, swapping from a regular to either a system or a combi boiler will improve your water pressure.

However, it may be best to stick with a regular boiler system, but to upgrade to a more efficient model. For example, if you have an older property, the pipework may not be able to cope with the stronger water pressure a combi or system will deliver.

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 by all of these manufacturers, 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
  • Fits in a standard kitchen cupboard
  • 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 regular boiler for your home involves taking the time to compare different models. To do this, you'll need to know what to look for and compare. When comparing system boilers, here are some things to make note of:

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.


Boilers convert fuel into usable energy and how much of the fuel ends up being converted is reflected in the efficiency rating. Effectively, the higher the efficiency rating, the less fuel the boiler will need to use.


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 many 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 system boiler you're considering.

Customer reviews

You want to be confident that your new system boiler will be reliably heating your home for many years to come. Taking the time to read through reviews left by homeowners who have already installed a certain boiler will let you know if they've had any problems over the years.

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Regular boiler prices

There are several regular boilers available on the market by a number of manufacturers, meaning that there's a wide range of potential boiler prices from around £660 ranging upwards of £1,200.

Regular Boiler Model Average Price (excluding installation)
Baxi 400 £660 – £940
Ideal Logic Max Heat £700-£940
Vaillant ecoTEC Plus Regular £800-£1,200
Viessmann Vitodens 100-W Open Vent £900-£1,200
Worcester Bosch Greenstar Ri £800 – £1,100

This price range doesn't include the price of installation which will vary depending on the engineer carrying out the work.

Regular boiler installation costs

Boiler replacement costs will vary depending on the work involved. The potential cost of a gas boiler replacement could go up or down depending on a number of factors. Firstly, there's the type of boiler being installed.

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

Secondly, when weighing up the potential cost of a boiler replacement, you will also need to consider the installation itself. As the price of boilers can vary so can the rates charged by heating engineers for the installation. Factors that will have an impact on how much the installation will cost include:

  • Type of boiler being installed (a like-for-like replacement will cost less than a complete change of heating system)
  • Whether the boiler is moving to a new location
  • The rates charged by the installer (installers in London tend to be more expensive than those in other areas of the UK)
  • What size regular boiler do you need?

    Boiler Size
    The size of the regular boiler is one of the most important factors to consider. And 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 system boiler with the highest output rating. An output rating that's too high for your home could cause your energy bills to rise and if it's too low, it will struggle to meet demand.

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

    Bedrooms Bathrooms Radiators Recommended Output
    2 1 10 10-18 kW
    3 2-3 15 18-26 kW
    4 3+ 20 27-40 kW

    In addition to the size of the regular boiler, the cylinder will need to have sufficient capacity to meet the hot water demands of your home.

    What size hot water cylinder do you need?

    Blaze with hot water cylinder
    Unlike combi boilers, regular boilers don't provide domestic hot water on demand. Instead, hot water is stored in a cylinder until it needs to be delivered to a bath, tap or shower. This means they can meet a higher demand for hot water, which is ideal for properties with multiple bathrooms.

    The disadvantage to this is that when the hot water is used up, you have to wait for the cylinder to fill up again. The time it takes to refill with hot water will depend on the model but it typically ranges from 20 to 30 minutes.

    If you have a large home with several bathrooms you should choose a cylinder with a larger capacity.

    As a guide, the table below shows the cylinder capacity (litres) you should consider depending on the number of bathrooms in your property.

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

    Leading hot water cylinders include the Heatrae Sadia Megaflo, Worcester Bosch Greenstore and Viessmann Vitocell 200-V.

    You should check that your new regular boiler is compatible with the cylinder that you're considering. Additionally, if you're planning to invest in solar thermal in the future then the cylinder must be solar compatible.

    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. A gas-fired system boiler 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.

    Boiler Guide Team

    About the author

    Boiler Guide Team

    Boiler Guide has been home to a host of heating experts who have helped millions of UK homeowners searching for advice and guidance. If you’ve got heating questions, we’ll have the answers.

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