How high should an extractor hood be above the hob?

Two numbers govern how much of the plume a hood catches: how far it has to rise, and how wide the canopy is when it gets there. A plume spreads as it rises, so height and width trade against each other. Mounting height is also a safety constraint on gas, where the flame and the hot pan support are directly below the canopy.

Safety

What you'll need

• The hood's installation instructions
• The hob's installation instructions
• A tape measure
• A helper, for holding the hood while marking (optional)

Step by step

1. Read both sets of instructions and take the larger figure.The hood states a minimum above gas and above electric. The hob states a minimum to anything above it. They can differ, and the binding number is whichever is greater. This is the only figure that actually governs the installation.
2. Use the typical ranges as a sanity check, not as the specification.Induction and ceramic usually 65 to 75cm; gas usually 75cm or more, sometimes 80. If your instructions say something outside that, follow the instructions — some slim and some canopy designs differ.
3. Then go as low within the range as you can.Lower means the plume has spread less by the time it reaches the canopy, so more of it is caught. Every extra ten centimetres of height needs a disproportionately higher extraction rate to compensate for what escapes.
4. Check it against the height of the people who cook.A canopy at 65cm over a 90cm worktop is 155cm off the floor, which a tall cook will meet when leaning over a front pan. The usual answer is not to raise the hood but to choose a hood with a shallower canopy or an angled front.
5. Make the hood at least as wide as the hob.Width matters more than most people expect. A 60cm hood over a 70cm or 90cm hob cannot catch the plume from the outer rings at all. One size wider than the hob is the ideal, and it is the cheapest capture improvement available.
6. Check the depth of the canopy against the front burners.A shallow canopy leaves the front of the hob outside the capture area. On a deep hob, or one where the front zones are used most, canopy depth is as important as width.
7. Confirm the chimney will actually reach.Chimney hoods have a telescopic section with a minimum and maximum extent. On a high ceiling you may need an extension chimney; on a low one the chimney may not compress far enough for the height you want. Check before drilling.
8. Mark and mount to the fixings, then check with a pan.Before finalising, put your tallest pan on the rear zone and check the lid clears the canopy and that you can still see into the front pan. It is easier to adjust on paper than on a tiled wall.

Tips

• If the hood must go high for headroom, buy more extraction rather than accepting the loss. Height costs capture and the only compensation is airflow.
• Over an island, mount within the stated range and expect worse capture anyway, because there are no walls to contain the plume and cross-draughts pull it away.
• A hood mounted over a window is a common awkward case. Check the window opening does not foul the canopy before fixing anything.
• Angled and slimline hoods are designed to be mounted lower without hitting heads. If height is the problem, that geometry solves it better than raising a box canopy.

Common mistakes

• Mounting below the stated minimum over gas — It is a safety figure. A tall flame under an empty pan reaches the canopy, and the filters and canopy are not designed for that heat.
• Fitting a hood narrower than the hob — The outer zones' plume rises outside the canopy entirely. No amount of extraction rate compensates for a capture area that does not cover the source.
• Setting the height from the wall units rather than the hob — The relationship that matters is hood to hob. Lining a hood up with the bottom of the adjacent wall units looks neat and frequently puts it far too high.

Questions people ask