LPG is an alternative fuel which is cheaper than petrol and diesel – but is the cost of an engine conversion worthwhile?

We see how much it costs to convert five popular UK cars to run on LPG and how much money they could save you.

What is LPG?

Liquefied Petroleum Gas (LPG) – or Autogas – is an alternative fuel which costs about half the price of petrol and diesel and cars emit less CO2 when powered by it.

Can my car run on LPG?

Most engines can be converted to run on LPG, but not all – check with a UKLPGA-approved installer - the UK trade association for LPG. Converted engines are bi-fuel, which means they can run on either petrol and LPG, both stored in different tanks. If you’re running low on one type, flick the switch on your dashboard to change to the other.

It’s not currently possible to convert a diesel engine to run on LPG and diesel.

How much does a conversion cost?

Costs start from about £1,600, depending on car make and model. The UKLPGA claims this cost will be recouped from lower running costs.

We found out how much it costs to convert the following cars and how much they could save you on fuel:

Ford Focus

Cost: £1,956
Annual fuel saving: £578
How long until you save: 3 years and 4 months

The Ford Focus 1.6-litre Ghia is one of the UK’s most popular hatchbacks – and costs £1,400 for petrol each year. The same car running on LPG will cost £823 per year.

Vauxhall Astra

Cost: £1,921
Annual fuel saving: £526
How long until you save: 3 years and 6 months

It costs £1,276 per year to run a 1.4-litre Vauxhall Astra on petrol, or £750 if it runs on LPG.

Audi A4

Cost: £1,925
Annual fuel saving: £794
How long until you save: 2 years and 5 months

Running an Audi A4 saloon will save you almost £800 per year on fuel – and it’ll take two and a half years before the initial switch to LPG is paid back.

Renault Clio

Cost: £1,921
Annual fuel saving: £509
How long until you save: 3 years and 9 months

The standard 1.2-litre Renault Clio will reach savings of more than £2,000 in fuel costs after four years of driving on LPG.

Peugeot 206

Cost: £1,921
Annual fuel saving: £603
How long until you save: 3 years and 2 months

If you drive an LPG-powered Peugeot 206 you’ll spend £860 per year on fuel, compared to £1,462 in petrol.

All cars are based on an annual mileage of 10,000 miles. Most conversions take around three working days to complete.

To find out how much it’ll cost to convert your car, visit greenfuel.org.uk.

Where can I get an LPG conversion?

View the UKLPG’s map of approved installers.

Where can I fill up with LPG?

View the UKLPG’s map of UK refuelling stations. There are currently more than 1,400 LPG refuelling stations in the UK. Alternatively you can visit Calor's website, who also supply LPG.

Do LPG engines have poor fuel economy?

The mpg rate for LPG cars is around 20 per cent less than petrol. However, as LPG generally costs half the price of petrol, you should still save money.

Do I need to inform the DVLA of a change?

Yes. Qualifying vehicles will receive a road tax discount.

Will my cost of insurance increase?

Most insurance companies won’t charge a premium if your engine is converted by your car manufacturer or an LPGA-approved installer, but you must inform your insurance company of the change.

Will I be exempt from the London Congestion Charge?

Yes – but only the cleanest LPG vehicles qualify for a full discount. Registration costs £10 per year and has to be renewed each year. For more information read our complete guide to the London Congestion Charge.

Can I buy an LPG car from new?

Yes. Some manufacturers which offer new LPG cars include:

• Vauxhall
• Ford
• Citroen
• Diahatsu
• Fiat
• Mercedes
• Nissan
• Diahatsu
• Proton
• LDV vans