Car hire companies have been ordered to treat customers more fairly after the European Union found complaints about rental firms have doubled in recent years.

EU consumer body the European Consumer Centres Network said that in 2016 it received twice as many complaints about the car rental sector as it did in 2010.

Working with the European Commission (EC), five major firms – Avis, Europcar, Enterprise, Hertz and Sixt – have made improvements to address the types of issues reported and to comply with EU consumer rules. These companies represent two-thirds of the EU's car hire market.

But while the EC and the national consumer authorities involved are satisfied with the changes brought in by these five firms, they have warned they will continue to "monitor the car rental market closely", stressing that all car hire companies, agencies and price comparison sites "should offer the same level of transparency on the service and the cost".

EU trade association Leaseurope is developing the consumer guidelines for the whole car rental sector.

For full help on what to watch out for when renting a car, see our Cheap Car Hire guide.

What must firms do under the new EU rules?

The consumer improvements unveiled by the EC apply to cars hired for use across the EU, including in the UK. The key rules are:

  • Total booking price to include all compulsory charges. For example, when winter tyres are compulsory by law in some countries, the headline price of renting a car must include winter tyre fees.
  • Clear and simple language. Customers must be provided with clear information about important aspects of the rental agreement, such as whether mileage is included, the fuel policy, the cancellation policy and deposit requirements.
  • Clear information on insurance 'extras'. Customers must be provided with clear pricing and details of optional extras – in particular for insurance excess 'waivers' that reduce what you have to pay in case of damage. It must be made clear what these extras cover before the customer books.
  • Transparent fuel policies. Customers must always have the option to get a car with a full tank and bring it back full.
  • Clear procedure for vehicle inspection. Customers must be provided with reasons for damage surcharges and evidence of any damage, before the payment is taken, and the customer must have the chance to challenge damage charges.

In a related move facilitated by the EC, the Competition and Markets Authority (CMA) wrote to price comparison sites last summer, warning them to adhere to consumer law, and in January 2016 Avis, Enterprise, Europcar, Sixt and Hertz committed to introducing a raft of pricing and policy transparency improvements within the UK.

It's still unclear how the UK exiting the EU will affect enforcement of these improvements, with the CMA telling MoneySavingExpert.com that it would depend on the precise terms of the Brexit deal.

What does the EU say?

Věra Jourová, EU Commissioner for Justice, Consumers and Gender Equality, said it was a "great day for European consumers".

She added: "We worked hard with the car rental companies to guarantee that people across the EU can rent a car and are treated fairly – no matter where in the EU they rent a car... Consumers across Europe can now enjoy their rights and be better protected."