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LPG Boilers Explained - Adaptable To Calor Futuria Liquid BioGas


It is estimated that the majority of the 1.3 million UK homes that are not connected to the mains gas grid use an oil-fired boiler as their main heating source. While these boilers have many benefits and are effective, they also produce significant levels of carbon which is a significant contributor to global warming.

When the time comes to replace an oil boiler, or to switch to LPG,  many of these home owners are choosing to make the switch from oil to a cleaner energy source such as a Liquefied Petroleum Gas (LPG) powered boiler. The boiler is fed from either an external LPG propane storage tank or via large externally stored LPG propane gas bottles (for bottled LPG consumption rates explained please go here).

Liquid Petroleum Gas (LPG) is a combination of propane and butane stored under moderate pressure. It is widely available in the UK and is recognised as a low carbon and low polluting fuel. There is also an even greener alternate LPG biofuel on the market which can power all current LPG products and appliances.


Because LPG is 250 times denser as a liquid than as a gas, a large quantity of LPG can be stored in a small space. This makes an LPG boiler an ideal choice for installing in a wide variety of property sizes.

LPG Boiler Types


There is a wide choice of LPG boiler options available on the UK market. These include dedicated LPG boilers, standard natural gas boilers that can be adapted using an LPG conversion kit, and boilers which automatically adapt to the properties of LPG without the need for a conversion kit. 


Like mains gas and oil boilers, LPG boilers are available as combi boilers, regular boilers, and system boilers. 


Combi LPG Boilers

Combi boilers offer a combination of hot water production for both taps and radiators. Their compact nature makes them increasingly popular within smaller homes. These appliances work by heating water within the boiler system, as and when hot water is required.

All modern combi boilers include condensing technology to increase their efficiency. This means that during heating, excess water vapour condensation is gathered to be recycled. This uses less fuel and offers savings on energy bills.

Condensing LPG boilers are best suited for small-to-medium-sized properties with no more than 4 bedrooms.

Regular LPG Boilers

Generally considered to be the traditional method of heating a home, regular boilers are the preferred choice when plenty of hot water is required at the same time. The system operates with two water tanks for hot and cold storage. This generally requires a large amount of storage space in the home.

If the property already has a cylinder, a boiler, and a storage tank, then a regular LPG boiler is a good substitute to simply replace the in-situ boiler without installing everything else.

System LPG Boilers

System boilers are one of the best boilers for homes with more than one bathroom as they are also compact to store. They tend to be highly efficient and can be quick and easy to install. 

Due to a lack of cold water storage, the system takes up less space within the home. Instead, many of the heating components are housed inside the appliance. Hot water is then stored within cylinders to ensure an efficient supply of hot water as it is needed.

LPG Boiler Costs


An LPG boiler costs less to buy than an oil boiler in general terms, when comparing similar power outputs and capabilities.

Obviously, the better the standard of LPG boiler, the more expensive it will be, but that is the same for any type of boiler, and oil boilers also vary in cost due to build quality, reliability and other factors.

Put simply, in choosing LPG for central heating, the buyer will get a better boiler than paying the same price for the oil alternative.

The average annual cost for heating and hot water using LPG in the UK is £796 pa (compared to oil-fired costs of £672 pa, and all-electric costs of £2,235 pa), this is based on a 3-4 bedroom house consuming around 12,000 kWh a year. This figure is derived by using the average cost of LPG across the UK in 2020 and then multiplying this by the amount of kWh used on average by a medium gas-energy user according to Ofgem.

Although LPG boilers are usually more expensive to run than oil boilers, they are cheaper to buy and install and can easily be combined with renewable energy sources. LPG is also a highly efficient fuel which gives a good return on every unit of energy used. The higher the energy efficiency of a boiler, the less it will cost to heat a home as less energy is wasted by the boiler itself  in simply performing its job correctly. 

By changing to a new A-rated LPG boiler, savings of between £300 – £600 per year are achievable.

It should be noted that the cost of running an LPG boiler is dependent on a number of factors, including :-

  • The size of the household and its hot water demands.

  • The size of the property and the number of radiators installed.

LPG Boiler Power -  What kW Power Is Required ?

Deciding on the right LPG boiler for a property greatly depends on the output (kW) level required to achieve maximum energy and cost efficiency, and to ensure that the water needs are met. All boilers have an output level which indicates the power of the boiler as well as how much it will cost to run.

LPG boilers come in 3 separate kW power output groupings :-


  • 24kW – 27kW

  • 28kW – 34kW

  • 35kW – 42kW

The following guidelines should assist in choosing the appropriately powered boiler for a given property size :-

a) Property Size :- 1-2 Bedrooms, 1 Bathroom, 10 (or less) Radiators : A 24kW – 27kW Output Boiler Is Required. 


b) Property Size :- 3-4 Bedrooms, 1-2 Bathrooms, 8-15 Radiators : A 28kW – 34kW Output Boiler Is Required.

c) Property Size :- > 4 Bedrooms, 2+ Bathrooms, 15-20 Radiators : A 35kW- 42kW Output Boiler Is Required.

The above are only guidelines, and if the household has a greater demand for heat and hot water created by 'extra' living space such as a converted loft, a conservatory, or en-suites and shower rooms, then a larger boiler will be required to service that demand.

The standard of insulation witihin a property also plays a part in the boiler output that is required because newer properties have better insulation than older properties and can therefore manage on a lower output. 

Advantages & Disadvantages Of LPG Boilers

Advantages Of LPG Boilers :-

  • LPG boilers are cheaper to buy and install than oil boilers.

  • Widely available across the UK and easy to transport.

  • LPG does not contain sulphur, so it burns cleaner than oil.

  • A more environmentally friendly choice than oil.

  • LPG is a highly efficient fuel, providing a good return on investment.

  • LPG boilers can be utilised with renewable energy sources.


Disadvantages Of LPG Boilers :-

  • The boiler, LPG tank and all appliances will need to be annually serviced.

UK LPG Boiler Brands

There are several leading UK LPG Boiler brands, and these are listed below in alphabetical order with links to their websites :-


Please do not contact Angus Maciver Ltd about the technical aspects of LPG boilers or their purchase and installation. For any of these types of enquiries you are advised to contact a local Gas Safe Registered plumber, gas engineer, or building contractor. For bottled LPG consumption rates explained please go here.

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