LPG Explained Re July 23, 2021

LPG Explained


You may notice whilst shopping online for your new or replacement boiler, that many boiler models will note that they also come in LPG. But what does this mean? This blog aims to explain what LPG is, what type of LPG boiler you need for your home, as well as their prices and installation costs.

What is LPG?

LPG stands for Liquified Petroleum Gas. LPG boilers are often used in homes that are not connected or close to a national grid and used as an alternative to natural gas.

Natural gas is preferably used in many households as it poses less of a risk. However, unless it is accessible in pipe form, for example, connect to your boiler via pipework, then it can not be used. This is where LPG comes in handy. 

You can convert natural gas into LPG, which can then be stored in a tank or canister, which is a lot more convenient for many, especially for those who are off-grid in more rural areas. This is because the gases liquify at only moderate pressure, meaning that the fuel can be stored and transported conveniently in a concentrated liquid form. It is also 250 times denser as a liquid than as a gas, resulting in a relatively large quantity of fuel being able to be stored in a small space such as a boiler. 

LPG’s adaptability means that it can provide an energy solution for several applications, as well as for heating, hot water and cooking. 

LPG is a by-product of crude oil refinement and is therefore classed as a fossil fuel. LPG is a chemical mix of two flammable, non-toxic gases called propane and butane. These chemicals are called hydrocarbons, which means that their molecules are made up of a combination of hydrogen and carbon atoms. LPG can also contain a variant of butane, called isobutene on occasions. 

Propane is typically used to create LPG at is not affected by freezing temperatures as it has a much lower boiling point making it better for all-year-round outdoor use in colder climates. Household tanks are more likely to contain a majority of propane to allow slow-burning at lower temperatures.

About 60% of the world supply of LPG comes from the separation of natural gas products, and 40% is a by-product from the distillation of crude oil.

LPG is recognised as a secure fuel supply and is produced in vast quantities in the UK. It is also a low carbon and low polluting fossil fuel.

LPG has the advantage of becoming liquid when under pressure, and reverting to gases at atmospheric pressure. As a result, it can be stored conveniently as a liquid. This provides an advantage over natural gas. It is typically used in a ‘wet’ heating system with an LPG fired boiler. This heats water which in turn provides central heating.

What type of LPG boiler do I need?

Similarly to Natural Gas boilers, LPG boilers are also available as a Combi, System or Regular boiler.

What is an LPG Combi Boiler?

Combination or ‘combi’ boiler for short are loved by many households, thanks to their compact and lightweight design. Combi boilers heat water as and when you need it, ideal for homes with a higher demand for instant hot water. However, they are limited to the amount of water they can supply. For example, if you have a 30-minute shower, you will see a noticeable drop in the temperature of your water by the end of it. 

If you have a larger property with a high demand for hot water, a system or regular boiler may be more beneficial for you. If you want to learn more about how a combi boiler works, click here.

What is an LPG System Boiler?

System boilers are ideal for bigger homes that need instant hot water or homes that need to run the shower and the taps at the same time. 

However, you must consider the additional space you will need for your hot water cylinder that you will need to store your hot water. These are typically located in an airing cupboard or similar sized space in your home.

What is an LPG Regular Boiler?

Regular boilers are great for homes with a high demand for instant hot water, however, they require a lot of room in your home. 

You will need the space for an additional hot water cylinder and water storage tank. These are installed in your airing cupboard and the attic of your home. The price of your LPG boiler installation is going to be much higher with this upgrade, in comparison to just replacing the type of boiler you already have.

What KW LPG boiler do I need?

When it comes to the kW outputs of your boiler, it can all become a little confusing. Unless you’re a Gas Engineer, we don’t expect you to know what kW means or how it relates to your boiler. If you want more information on what kW means when it comes to your boiler, we have a separate blog for that (cheeky self-promo). 

This section will explain what kW LPG you need in the most simple way.  So simple, we’ve put the information in a table for you:

Property SizeNumber of RadiatorsNumber of BedroomskW Output Needed

Small Properties

1-2 bedrooms

10 or less124kW – 27kW

Medium Size Properties

3-4 bedrooms

Between 8 and 141-229kW – 34kW

Large Properties 

4+ bedrooms

Between 14 and  20235kW – 42kW

Please note that this is a guideline and may not be completely accurate for your home. It is always best to ask your Gas Safe Engineer or a boiler manufacturer for advice if you are unsure.

How much do LPG boilers cost to run?

The running costs of LPG boilers are not hugely dissimilar to those of oil boilers and, like oil boilers, LPG boilers require a storage tank and a fuel feed. The cost of installing and running an LPG system will vary depending on several factors:

  • If you choose to rent or buy a storage tank
  • The size of your home
  • How many radiators you have in your home
  • How you use your heating

Pros and cons of LPG boilers

Pros of LPG

If your home isn’t connected to the mains gas grid, there are many advantages to installing an LPG boiler over a unit fueled by oil:

  • LPG is a highly efficient fuel.
  • It produces very low sulphur emissions.
  • Combustion is virtually odourless compared to oil.
  • By law, anyone carrying out work on your boiler is required to be on the Gas Safe Register.

Cons of LPG

Even though there are many advantages to LPG boilers, before committing to a new boiler it’s always important to consider the possible downsides:

  • New installations can be costly.
  • Prices for this type of fuel are on the rise.
  • LPG is not considered to be a clean source of energy as it produces carbon dioxide when burnt.
  • LPG boilers need to be serviced annually to maintain efficiency.

LPG boiler installation cost

The overall cost of your LPG boiler and installation cost can vary depending on your installer as well as the boiler model. Other factors that may affect your overall installation costs are the following:


First, you have labour prices. Are you using a large national company, or in an area with a high cost of living like London? There’s a good chance the price you pay for labour, is going to be much higher than someone using a cheaper local installer in the Midlands or the North.


It is important to note that additional parts and materials may be needed. If these are not included in your original quotes, this can affect the final costs. One thing worth noting is a lot of installers will include a boiler filter, that catches debris that otherwise would damage the boiler. If another installer isn’t including one as part of the price, you’d be adding around £200 to your quote.


And, upgrades can cost a lot of money. Whether that’s a gas main upgrade, or you want to switch your regular/system for an LPG combi boiler or additional controls.

For more information about boiler installation costs, we have a separate blog that covers this for you to read 😊

Can I fit my own LPG boiler?

The simple answer is no. There seems to be a bit of confusion when it comes to who can fit an LPG boiler, however, legally, you will need a Gas Safe registered engineer that has also completed their LPG qualification to install your LPG boiler. For residential property, they will need CCLP1 PD.

The top 3 best LPG boilers

We’d always recommend sticking to top brands. Sure, the boiler is a large cost. But, with fittings and installation, the total cost can almost double. For the small difference of around £100-200 for a quality boiler brand, it could last between 7-10 years more.

You can’t really go wrong with products from any brand below, however, to find the best boiler for you, you can take our 90-second survey which asks you a few simple questions about your current heating system and what you are looking for, and bobs your uncle!

  • Worcester Bosch
  • Ideal Boilers
  • Viessmann
  • Potterton
  • Vaillant
  • Baxi
  • Vokera Boiler

Worcester Bosch Greenstar i

Worcester Bosch is an incredibly popular and successful boiler manufacturer who have been in business for a long time now. 

The Worcester Bosch Greenstar I range achieves an efficiency rating of 92% energy efficiency and has an ErP A-rating. With these ratings, this boiler could potentially help you to lower your energy bills in the long run.

This boiler range has an output that reaches 30kW for both the combi and system boiler models. 

Key Features:

  • Easy to use and easy to maintain
  • Full graphic display
  • Magnetic flap cover for easy access
  • 5 Years Warranty
  • Wall-mounted
  • Rear piping

Viessmann Vitodens Open Vent 100-W

The Viessmann Vitodens has an energy efficiency of around 97%, which easily scores it an A rating. The Vitodens 100-W range is available as a combi, system and regular boiler model, so there is an option for everyone. 

One of the biggest advantages that Viessmann have over other boiler manufacturers is the fact that they use patented Inox-Radial Stainless-Steel Heat Exchangers, which are not only more durable and resilient than the aluminium heat exchangers used in many competitor boilers, they are also extremely resilient to corrosion.  This means they will last longer, and be just as efficient 10 years down the line. 

Key Features:

  • Patented Inox-Radial stainless steel heat exchanger
  • Condensate and pressure release valve combined into one
  • Built-in shock arresters (reduces/avoids water hammer)
  • 10-year comprehensive extended warranty
  • Wall-mounted
  • Easy to use
  • Compact, making it easier to site
  • Lightweight

Ideal Vogue Gen2 Boiler

Undoubtedly, the Ideal Vogue Gen 2 is one of the strongest and best performing condensing boilers on the market. 

Ideal is known for being a more affordable boiler brand, however, this is definitely a good boiler that you should not pass on so easily.

This boiler is capable of achieving energy efficiency of up to 93%, and an ErP A-rating, helping you save money on your energy bills. 

Key Features:

  • Crystal clear LCD monitor display for easy use
  • Error and fault logging
  • Wall-mounted
  • Easy to use
  • Easy to maintain
  • Lightweight
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