Warning – some hotel comparison sites highlight 'deals' costing 20% more than the cheapest

Analysis of 100 hotel listings across Trivago and Kayak has revealed that the most prominently displayed deals – those shown in the biggest font and isolated from the others – could often be found cheaper in the very same search results.

We discovered that the booking site highlighted for each hotel quoted a price that on average was 3.2% more expensive than the cheapest. In one case, a hotel deal being shown in the top position was over 20% more expensive than the best available.

With Trivago, the most prominently displayed deal was pricier than the cheapest on 30 out of the 50 hotels we looked at. On Kayak, it was costlier than the cheapest on 23 out of the 50. We also checked Skyscanner and TravelSupermarket but didn't spot the same issues.

When pressed on the price discrepancy, Trivago and Kayak explained that they used a variety of factors when deciding which hotel deals to highlight, including the revenue the deals would make for them.

Comparisons scour deals from numerous hotel booking sites and travel agents to find you the cheapest place to book a room in seconds. If you're using a hotel comparison site, make sure you check all the deals for a particular hotel – not just the one highlighted.

We've previously warned that at least eight major booking sites – including Booking.com, Ebookers and Expedia – may rank hotels higher in their default search results if they receive commission for reservations. See our Booking sites' commission warning MSE News story for more.

For how to unearth the best deals, check out our Cheap Hotels guide.

What exactly did our investigation find?

We searched Trivago and Kayak for hotels in 10 cities across the world – Cape Town, Lima, Lisbon, London, Madrid, Mexico City, New York, Paris, Sydney and Tokyo – and looked at the top five hotels listed at each location.

We searched for a range of stay lengths – one to seven days – and for a range of travelling parties – from a single person to a family of four – but we used the default ordering setting on the hotels each time.

On Trivago, hotels and various booking offers are displayed as below, with one deal pulled out and highlighted on the right-hand side. This wasn't always the cheapest offer, as in this case, which shows a search result for a Paris hotel:

Similarly, on Kayak, listings appear as below:

Overall, across the 100 listings we looked at, we found that the most prominent listing on Trivago was an average of 3.9% more expensive than the cheapest available, whereas on Kayak, it was 2.5% more expensive. Overall, the biggest discrepancy on Trivago was 20.6%, while on Kayak it was 11.8%.

Why are the 'top deals' not always the cheapest?

We asked Kayak and Trivago why they both highlighted booking sites that weren't the cheapest.

Kayak told us it ordered results and selected the provider which it highlighted on the right-hand side based on a "composite score" that includes overall predicted revenue and quality metrics including customer support and price competitiveness. It also noted that it does show the cheapest deal available in green, if it isn't highlighted on the right.

Similarly Trivago told us its algorithm takes into account a "number of relevant factors", such as search criteria, the offer's price, its "general attractiveness" and the payment booking sites provide it with when a user clicks on an offer. 

'You need to be on your guard when booking'

Guy Anker, deputy editor of MoneySavingExpert.com, said: "Comparison sites such as Kayak and Trivago are a good place to find cheap hotel prices but our investigation shows you need to be on your guard and double-check everything or you could inadvertently overpay.

"Whatever their excuses I'm sure these sites know exactly what they're doing by highlighting pricier deals to boost their coffers as they'll know people often click on the most prominent link. But if you spend only a few seconds more checking the detail it could be worth its weight in cash."

Beyond this, when using a hotel broker or comparison site, always remember that a range of factors affects the default results and you can instead use different filters to search by the factors that are most important to you, eg, price or reviews. If you've time, check multiple sites to ensure you get the best price too.

For more help on how to find the best hotel deals, see our Cheap Hotels guide.