Different types of central heating boilers in the UK

A boiler is the main component of a domestic central heating system as it supplies hot water across all the taps and radiators in the house.

The basic concept of a central heating boiler is straightforward. A boiler, In simple words, is a gas-fueled, easily regulated furnace.

It is installed at a convenient location in the house, such as in the kitchen or bathroom for easy access and it requires water, which is moved by an electrically powered pump, to transport heat to radiators across all the rooms in the house.

How does a boiler work?

To know which boilers can work the best for which type of home space, it is important to understand the basic working mechanism of the boilers.

Central heating boilers are similar to a large furnace that receives a constant supply of natural gas from a pipeline that connects to a gas main in the street.

To start the process of heating, one needs to turn on the boiler with an electric switch. This will pen up a valve that enables the gas to enter a sealed combustion chamber inside the boiler.

The chamber has a series of tiny jets and an electrical ignition system to ignite them. The gas jets are directed at a heat exchanger that is connected to a cold water line. The heat exchanger absorbs the heat from the gas jets and heats the water to around 60 degrees Celsius.

The water pipe is a segment of a larger continuous pipe circuit which runs all around the house and across each hot-water radiator before returning to the boiler.

As the water passes through the radiators, some of its heat escapes, warming up the rooms, and by the time the water returns to the boiler it has cooled down considerably.

Hence, to maintain the water’s temperature it is necessary that the boiler keeps firing. The thermostat keeps the temperature of the boiler in check – it turns the boiler off when it is hot enough and vice-versa.     

Different types of boilers used in the UK

Even though most boilers perform the relatively similar basic operations of burning fuel and transferring water to radiators and taps, each boiler type operates in a different way from the others.

The following sections explain how each boiler type provides warmth and hot water:

Combi boilers

Combi boilers or combination boilers are the most common types of boilers used in the UK, however, they are mostly used in smaller spaces.

They provide both, heating and hot water across the home. A Combination boiler does not need any additional tanks or cylinders and its independent heat exchangers are directly connected to your radiators as well as the hot-water supply.

These types of boilers come with control valves and the purpose is to control the supply of heat and that is the reason why they cannot provide both at one time.

System boilers

System boilers are pressurized insulated systems. A filling mechanism draws cold water straight from the mains supply,  this eliminates the need for cold water storage.

This water is heated before being transferred to either the hot-water storage container or the radiators. The system boiler will provide hot water to the taps when it is required.

The average system boiler is still quite economically viable and efficient to run, however, they can be way too expensive in a smaller household where the family members do not require a lot of hot water at any given time.

A system boiler is an excellent solution for homes with several bathrooms. They may, however, require more maintenance and space to be installed effectively.

Conventional boilers

The boiler, cold water tank, and hot water storage cylinder are all present in a traditional boiler.

The boiler may offer both hot water and heating water since it feeds hot water to both the central heating system and the storage cylinder.

A cold-water tank, which is usually positioned in higher areas of the house, such as the attic or loft, provides cold water to the boiler. Gravity aids in the filling of the boiler.

The boiler will provide hot water to the hot-water cylinder or the radiators once it has started.

One should be able to use water from many taps at the same time as long as the cylinder contains enough hot water. A traditional heating system is very likely to be installed in older properties.

Is it possible to change the type of boiler I use in my home?

It is entirely possible to modify the type of boiler one possesses. Due to the changes in family needs, boilers are often replaced after every 10-15 years.

The boilers need to be changed keeping some critical factors in mind which are discussed in the following section.

How to choose a boiler for your home?

Choosing the right type of boiler for any home should be based on the following parameters:

Size of the property

A boiler is the main heating system for houses hence it is important to choose a boiler that emits enough heat to keep the property warm.

The size of a domestic boiler is determined by its heat generation efficiency, which normally ranges from 5 to 35 kW.

Water Usage

The usage of water is directly proportional to the number of family members. A 24-30 kW boiler is ideal for most houses with a single bath and shower.

If there is an additional en-suite bathroom, a larger 30-35 kW boiler may be preferable. In larger homes where everyone has a separate bathroom, a system boiler that stores hot water in a storage cylinder may be ideal.

Available space

The space is a good deciding factor for the type of boiler one should invest in. If the space is tiny then it is better to opt for a boiler that does not need a separate hot water storage tank.

This article has conducted thorough research about the benefits and drawbacks of various types of boilers, as this can save hundreds of dollars on heating expenses and help meet one’s needs better.