How we test venting hobs

A venting hob, also known as an air-vented induction hob is an induction hob with a downdraft extractor built into it. Like a washer-dryer it does the job of two appliances in one and as such, we test their capabilities both as hobs and extractors.

Our test lab sorts the best performing venting hobs from the rest. We put them through our rigorous test programme so you can be sure that the ones we recommend live up to their claims.

For shopping advice and to see the best we've tested, visit our guide to the Best venting hobs.

Why our venting hob tests are different

Many websites review venting hobs using an individual tester to generate scores based on that individual's preferences, or a small number of cursory tests. Free-to-access sites also typically receive appliances free of charge directly from manufacturers or their PR representatives.

As well as using multiple testers in a laboratory setting, the Which? overall percentage score is calculated purely on the measurements and ratings supplied by the lab, meaning there is no room for unconscious bias when giving a rating. We also buy every single appliance we test - we do not accept free samples for any of our full lab tests.

What are Which? Best Buys and Don't Buys?

Best Buys are given to venting hobs that impress most in our tests. A venting hob that scores 77% or more is a Best Buy and comes with a firm overall recommendation, although you should still read our reviews to check for any weaknesses that might impact your buying decision. Any venting hob that scores 45% or lower is a Don't Buy that's best avoided.

• Best Buy venting hobs typically tick the most important boxes - they are quick to heat up, stick closely to the correct temperature and the downdraft extractor pulls in any steam and grease that would otherwise linger in your kitchen. 
• Don't Buy venting hobs tend to fall down in the most important areas - they leave too much water and grease floating around your kitchen, they may be cramped and difficult to use, or they might have poor heat control that makes it hard to cook your food as you need it. 

Find out which models are better than the rest by reading our venting hobs reviews.

How is the Which? score calculated?

The Which? overall score is a percentage. This score only takes into account the results of our tests and ignores price completely.

This means that all venting hobs are tested on exactly the same scale, so you can compare any venting hob at any price and how it measure up against its rivals in key areas.

A Which? overall score is made up of dozens of individual tests and checks, from key factors such as the hob's speed of heating up, and how well the extractor removes steam and odours. 

To keep things simple, the most important scores are shown as star ratings out of five in the test results section of each review. This gives you an easy-to-compare list of the strengths and weaknesses of different models.

How the overall venting hob test score is calculated

The following assessments go into making the final overall score for each venting hob we review. Because we know what's most important to you, some elements are more important than others, so carry different weights:

• 30% hob performance
• 30% extraction performance
• 20% ease of use
• 20% ease of cleaning

Read on to find out exactly what goes into each of these scores.

Our key testing criteria

The following are our key testing categories for venting hobs and how we evaluate each one.

Hob performance

Key question: How well does the hob heat up?

To see how quick and efficient a hob is, we time how long it takes to heat a pan of water from room temperature to 90°C, and we also record how much energy it uses in the process. 

The best hobs take less than four minutes to heat 1.5 litres of water, while the worst take closer to 11 minutes to do the same job.

Key question: How good is the hob at simmering?

We heat a pan of baked beans and then leave it to keep just warm to find out how gently a hob can heat and to see how responsive the controls are.

The best hobs are very easy to control and adjust, while the worst give poor results and prove difficult to use in our trial.

Key question: What is the hob like at frying?

To see how well heat spreads across the base of a pan, we heat a frying pan to 200°C and take a photo with a thermal imaging camera. This shows how well distributed the heat is across the surface area of the pan. The best hobs will heat the base of the pan evenly, and so deliver a perfect pancake, but the worst will leave some areas much cooler leaving your food liable to be cooked improperly.

Extraction performance

Key question: How well does the venting hob remove steam, grease and odours?  

To keep your air clear and your kitchen clean, we put each venting hob through a series of tests to make sure it's capable of extracting the air and venting it outside. 

• We boil four pans of water on the hob until our test chamber has a humidity level of 90% and then we see how long it takes for the venting hob to reduce the humidity of the room to 60%.
• We drip fat into a hot pan for 30 minutes and measure the grease filters before and after to see how much is trapped in the venting hob's filters. The best will capture about 80% of the grease produced by frying.
• We cook methyl ethyl ketone, a pungent chemical with a strong synthetic smell, to see how effectively the venting hob removes odours from the room. We use a flame ionisation detector in four points around the room before and after we start extracting to see the difference. 

Ease of use

Key question: How easy is it to use both the hob and the extractor?

We have three expert assessors to find out how easy the venting hob is to use. We assess how easy it is to operate the controls, check how clear the markings are and see whether there’s enough space to use all cooking zones at the same time. And we listen out for any unusual or irritating noises. 

We also find out how easy it is to replace grease filters and control the downdraft extractor in conjunction with the hob.

Ease of cleaning

Key question: How easy is it to clean? 

To see how easy each hob is to clean, we heat cooking oil and allow it to splatter on the burners, and we also allow a pan of rice to boil over. The grimy hobs are then left to dry overnight after which we attempt to clean them with washing-up liquid and a sponge.

We'll also clean the grease filters to see how tricky it is to make these grease traps pristine again. 

Venting hob safety testing

As well as the tests outlined above, we also put venting hobs through fire safety testing to make sure that they pass requirements created to keep you safe in your home. 

Venting hobs have fans which pull things towards them. This could include a flame on your hob, in an event such as a fire in your pan. Standards require certain components in your venting hob to be sufficiently fire resistant if they come into contact with a naked flame. 

If a venting hob fails any fire safety test, it automatically becomes a Don't Buy, and this is highlighted with a safety alert banner on our review. 

Our fire tests follow appropriate British and European Standards and include testing how long individual components within a venting hob burn for if they are ignited.

Find a great venting hob with Which? reviews

Venting hobs are expensive, but spending a lot doesn't necessarily mean you'll get a better product. We've found venting hobs that are pricey and failed our safety testing, making them Don't Buys.

Our venting hobs reviews will help you look beyond the price when shopping, and will help you to shop with confidence.