Could LPG save you a fortune?

Would you like to cut 40% off your motoring fuel bill? Who wouldn’t?

Close up of someone filling their car at a petrol station

Save money on your car insurance

Start a quote

One option that could be worth a look is converting your car to run on liquid petroleum gas (LPG). Not only is it easier on the pocket at the pumps, it’s also easier on the environment and could even cut your running costs further by getting you a reduction on your road tax.

And although it usually costs between £1,200 and £1,500 to convert your car to ‘bi-fuel’ – which means that it will run on both LPG and petrol – if you’re spending around £60 per week at the pumps the conversion should have paid for itself in a year or so because LPG is almost half the price of other fuels on the forecourts.

This is largely due to the fact that LPG has lower rates of fuel duty than other fuels: petrol, diesel and biofuels (biodiesel and bioethanol) are all subject to 61.0 p/litre in duty costs, LPG has a rate of just 37.3 p/kg.

(Quick note: LPG is a gas, so it is often measured by mass, not volume, which means prices are sometimes given per kilogram and not per litre.)

Despite the cheaper fuel costs there are still thought to be fewer than 200,000 cars running on LPG on the UK’s roads– a miniscule number when you consider there are over 31million cars registered in the UK.

So why aren’t more of us making the switch, particularly as petrol prices are soaring to such levels that the Office of Fair Trading (OFT) has launched a price review? Is it down to the installation costs, or a worry that the car’s performance could be affected? Or are people worried about the insurance implications?

Or is it down to good, old-fashioned apathy?

But before we get into that, let’s first let’s see what’s actually involved in converting your car to run on LPG… 

What’s involved in an LPG conversion?

Converting your car to run on LPG does require some major work that will see you parting with your car for the best part of three days and will see your bank account parting with the thick end of £1,500.

The process involves having a second, independent fuel system, including a secondary fuel tank, installed in your car, and this will come with a separate fuel gauge so you know when it’s time to refuel. Depending upon the type of car, you may also have to have an additional lubricating system fitted to avoid excessive wear on the engine.

That is why it is vital that you have the right sort of LPG system fitted in your car and make sure that it is fitted by one of the 200 or so LPGA approved installers. You can find your nearest, approved installer by clicking here. You should have the system serviced annually and any minor maintenance costs involved in this should cost between £25 and £50.


Around 90% of petrol cars currently registered in the UK can be converted to run on LPG. While diesel cars can also be converted, the process is a lot more complicated and is not recommended given the current technology.

Once installed, you simply fill up your new tank at a service station forecourt as you would your petrol tank. There’s no danger of putting in the wrong fuel or overfilling as the LPG hose has a unique nozzle and an automatic shut-off valve.

Even though you’ll be running your car on LPG, it’s still worth keeping your petrol tank topped up as you can still switch over to petrol at any time. If you happen to run out of gas the car should automatically switch back over to petrol.

But with over 1,400 LPG stations covering the length of the UK, from Southampton to Stornoway, you should never be too far away from an LPG filling station –  a full list of LPG refilling stations can be found at

Any problems with LPG?

Although LPG offers significant savings on fuel bills, is available at plenty of forecourts and saw 12,000 new conversions last year, you could argue that it hasn’t taken off as it should have. So what exactly is the problem?

One issue is that there is still something of a negative perception surrounding LPG. This is a legacy of the fact that some of the earlier installations resulted in a significant loss of boot space and were sometimes so poorly fitted they caused owners all manner of problems.

However, there have been significant technological advances made over the last five years or so, as Mike Champman of the UKLPG Association, explains: "The latest systems work with the engine management system, and are extremely reliable. Almost all petrol cars can be converted. Some of the newer direct-injection engines are not suitable, but to all other drivers, a correctly installed and maintained system will offer no problems. We know of many cars that have covered 250,000 miles on gas."

In addition, most LPG units are now either fitted in the spare wheel well in the boot or, in the case of 4x4 vehicles, under the chassis, so there is no longer a loss of boot space. If you have a tank fitted in the spare wheel well, it’s vital that you carry a foam tyre repair kit in lieu of your spare wheel – and it’s also worth investing in breakdown cover in case you ever have a complete blow-out.

Despite advances in LPG technology, some drivers who run their cars on LPG encounter a loss in power and performance. And there is usually about a 15%-20% drop in fuel efficiency when compared with running on unleaded petrol, something which can result in a range of just 150-200 miles on a full tank.

However, in reality, any drop in power is usually negligible and the lower miles-per-gallon ratio is more than offset by the lower fuel costs, which average at about half the price of petrol, meaning that LPG is still a cheaper option than unleaded.

What are the main benefits of LPG?

Aside from the obvious savings on fuel costs, running your car on LPG will make it a much greener machine, with a drop in CO2 emissions of around 20% and almost no particulate emissions. And, provided you inform the DVLA that you’ve converted to LPG, running a more environmentally friendly car will net you a reduction in road tax of £10 per year – not a massive saving, but a saving all the same.

Shelling out: LPG is almost half the price of petrol

As well as informing the DVLA that you have had your car converted to LPG, you need to inform your insurer as it is, to all intents and purposes, a modification. However, unlike most modifications, it shouldn’t result in an increase to your premium as it is not seen as any adding any greater risk to the vehicle.


Unfortunately, even though its more environmentally friendly, it’s unlikely that insurers will reduce your premium as they do with other eco-cars, nor will it get you a discount on the London congestion charge (currently £10 a day).

Running your car on LPG can also prolong the life of your engine. As a cleaner burning-fuel it actually reduces wear and tear on your engine and, provided the system has been fitted by an approved installer, it could actually increase the sell-on value of your car, particularly as people look to reduce running costs.

Please note: Any rates or deals mentioned in this article were available at the time of writing. Click on a highlighted product and apply direct.

Did you enjoy that? Why not share this article

Take control of your energy bills

Our handy tips and tools will help make sure you never overpay again

Popular guides