Should I convert my car to LPG?

The news that residents parking charges in London will be linked to the levels of carbon dioxide emissions of their vehicles has got us thinking about LPG – Liquid Petroleum Gas.

Those with cars that emit high levels of carbon dioxide will now pay three times more for their parking permits, if they live in the London Borough of Richmond.

Are there benefits in converting to LPG? Are there costs as well as environmental reasons to switch? We examine some of the arguments for and against in this article.

What is LPG?

LPG is a gas in liquid form, so filling your car with LPG is very similar to filling it with petrol or diesel. Built in safety measures during filling prevent spillage making LPG slightly more safe than petrol and about as safe as diesel.

LPG has major environmental benefits as it emits about 20% less carbon dioxide than petrol and less harmful particulates than diesel. This means that LPG powered cars and vans have far less polluting and green house effects than their petrol and diesel counterparts.

Because of major tax incentives, LPG costs about half the price of petrol or diesel – about 46p per litre at the moment. Apparently there is no performance degradation when using LPG, although we haven't tested this.

There are currently around 1200 petrol stations that sell LPG in the UK so there should be a supplier reasonably nearby to you.

Converting your vehicle to LPG

Converting your car to run on LPG must be undertaken by trained and qualified specialists who ideally belong to the LPGA. They will ensure that your car can be successfully converted and that there are no warranty issues with converting your car in this way.

You will also need to advise your insurance company about the conversion. Generally there should be no premium increases if the conversion has been undertaken by a LPGA approved installer.

Conversion costs vary, depending on your car, however they will be in the £1,500 to £2,000 range. Lets see if this is a wise investment.

Cost benefits with using LPG

Assuming it costs £2,000 to convert your car, and that it normally costs you £50 to fill your tank with petrol, you will need to fill your tank 80 times to recoup the conversion costs.

So if you fill your tank once a week, it will take about 18 months to pay for the conversion costs.

If you own a large “gas guzzling” car with poor fuel economy you will therefore benefit. Convert it and keep it for three years and you will save considerable amounts of money for at least 18 months of that time.

There are other cost benefits too

You can get 100% discounts on the London congestion charge if your LPG vehicle qualifies for the power shift register. At £8 a day, this could save you over £1000 a year if you drive into the London congestion charge zone regularly.

With the London congestion charge zone now extending further west, and with other cities considering adopting similar congestion charges, many people could benefit from these discounts.

Of course congestion charge savings dramatically reduce the pay back times of the conversion costs, so if you drive a 4×4 on the school run in London, you will be making considerable savings in less than a year, and you are helping the environment too.

Other points to consider

Cost savings depend on your car, your mileage and whether you have to pay congestion and parking charges linked to your car emissions. Savings can be dramatic, as we've shown and are a no brainer in certain circumstances.

You still have to be close to petrol stations that supply LPG, though you can have your car converted to run on both LPG and its normal fuel, for convenience.

The effect of LPG conversion on the depreciation of your car is an unknown, though it seems sensible to assume that a 4×4 type vehicle would probably depreciate less, particularly with increasing road duty and other green taxes being targeted at these vehicles.

So is there benefit in converting to LPG?

We have looked at the cost benefits and found there to be a strong financial case for converting to LPG, depending on your exact circumstances, and almost certainly for 4×4 drivers in cities, particularly London.

Switching to LPG has very strong environmental benefits so if you want to make an effort to reduce your carbon footprint and are willing to make a financial sacrifice with the conversion costs, or want to drive a large car, then converting to LPG is probably a good idea.