Induction cooktops

Find out how induction cooktops work and what to consider when buying one.

Saucepans on induction cooktop

Induction cooktops produce a high-frequency magnetic field. When you put cookware such as a steel-plated pan on to the magnetic field, energy is transferred into the metal.

The pan then heats up and cooks the food directly. And because the heat is generated inside the pan, the cooktop stays reasonably cool.

Induction cooktops are highly responsive – unlike a conventional radiant-ceramic cooktop. When you adjust the temperature, the change happens immediately.

You sometimes hear whistling or cracking sounds (especially if you’re using multi-layered saucepans), humming when you use high power levels and clicking when zones turn “on” or “off” or change their power levels. This is all perfectly normal.

Speed

We knew induction cooking was fast – but to see just how fast, we boiled 1 litre of water on 3 cooktops: induction, radiant-ceramic and gas.

The induction cooktop was at least 3 times faster at boiling water than the radiant-ceramic or gas models.

Approximate time to boil 1 litre of water
  • Induction: 2 minutes
  • Radiant-ceramic: 6 minutes
  • Gas: 8 minutes

Size and cooking zone layout

Before you buy an induction cooktop, think about what size you need and how many cooking zones you’re likely to use at once.

Induction cooktops mainly come in 3 size options – 60cm, 90cm or somewhere in between. They have 3 to 6 cooking zones and some zones can combine into a flexi-zone.

However, if you’re using all the zones at once, the cooking space can become quite cramped and cooking can begin to interfere with the controls, making them greasy and unresponsive to touch.

As a general rule, a 60cm model can accommodate 3 zones comfortably, 70-85cm cooktop 4 zones, and a 90cm model 5 zones.

You should also consider the cooking zone layout. A very good layout has the small and large cooking zones at the front, or all zones are the same size. This means you won’t be leaning across cooking zones when you’re stirring.

Power management

The power supply to the cooking zones works in a way that takes some getting used to. The cooking zones are organised into pairs (usually arranged as 1 pair on the left side and 1 pair on the right side).

The maximum available power is shared between the 2 cooking zones in a pair. When the “power boost” function is selected for 1 cooking zone, the additional power is made available by limiting the power of the other cooking zone in the pair. For some cooktops, the power boost function can only be used if the other cooking zone in the same pair is switched off. If you want maximum power in 2 pans, use 1 cooking zone in each pair.

For some induction cooktops, even when not using the “power boost” feature, if all cooking zones are in use at the same time, some cooking zones may be reduced in power. Check when buying whether the cooktop you want has any limitations.

Suitable cookware

Cookware used on induction cooktops must be made of ferrous (iron) materials. Induction cooktops won’t work unless you use magnetisable cookware.

Cast-iron cookware – including ceramic- or porcelain-coated cast iron – is fine. Some stainless-steel and multi-layered cookware is also suitable. But copper or aluminium pans won’t work unless they’ve got multi-layered bases with an outer layer of suitably ferrous material. Non-stick pans without an outer layer of iron won’t work either.

Most cookware will say whether it’s suitable for induction cooktops.

Tip: Take a magnet with you when shopping for cookware. If the magnet sticks to the base of a pan, the pan will work on an induction cooktop.

For induction cooktops to perform most efficiently, a pan’s base must cover at least 60-75% (depending on the model) of the cooking zone and be no more than the recommended maximum diameter. The cooktop’s manual will tell you the recommended maximum diameters.

To find suitable cookware, see our tests of pots and pans.

Safe with pacemakers?

The area around an induction cooktop is electromagnetically charged. It’s unlikely to affect pacemakers or other implanted electronic devices, but some pacemaker brands recommend you keep a distance of at least 60cm from an induction cooktop. Before you buy get advice on any possible safety concerns from the manufacturer of your pacemaker and your doctor.

Features to look for

If you are buying an induction cooktop, here’s what to consider.

Flexi-zones

Flexi-zones (sometimes called a “bridge function”), where both left or both right zones can be joined and operated as a large cooking zone, increase the flexibility of an induction cooktop. When joined, you can use large oval or rectangle pans on the cooktop. It’s important to keep stirring when using bridged zones as there is a cooler spot where the zones meet.

Safety sensors

These monitor the temperature of the bottom of the cookware. So if an empty pan’s left sitting on a zone that’s “on”, the sensor adjusts the power output to avoid damaging the cookware or the cooking zone.

Automatic switch-off

If a zone’s not in use, this feature switches it off after a pre-set time.

Power boost

A “boost” feature heats food or liquid quickly at the highest setting and then automatically reduces the heat to a pre-selected lower setting.

Residual-heat indicator

This is a light that stays on until the temperature gets down to a safe level.

Protection against overflows

The hob may shut down with a “beep” if a pan overflows on to the buttons. Remove the overflow, then begin cooking again.

Pan detection

When you remove a pan from the cooking zone, the zone stops operating – and a display symbol appears, telling you what’s happened (when you put the pan back the symbol disappears and cooking resumes). If you try to use cookware that’s not suitable, yet another display symbol lets you know what you’ve done (and after a short period the zone switches itself off).

Timers

For each cooking zone. Some models have separate timers for general kitchen use.

Memory

Allows you to programme the full cooking cycle for a particular preparation.

Auto heat-up

Allows the cooking zone to heat to a higher setting, then automatically turn down to a preset setting after a certain amount of time. This is handy if you’re cooking rice using the absorption method and want to bring it to the boil initially and then simmer.

Keep warm function

A very low simmer setting that can be used to keep food warm.

Other considerations

Installation issues

Induction cooktops need to be specially installed. The electronics shouldn’t be exposed to significant amounts of heat during cooking – and so they usually come with fan-cooled “heat sinks” to disperse the heat. (You may hear some noise from the heat-sink fans during and after cooking.)

Adequate ventilation space is also essential. The manufacturer’s installation dimensions must be carefully followed.

Not all induction cooktops can safely be installed above every brand of under-bench oven. Check the installation instructions to see which combinations are acceptable.

Tip: Be aware that manufacturers may try to steer you towards using one of their ovens, even though other brands would work fine.

Because they heat so quickly, these cooktops draw plenty of energy. A normal power socket has a 10-amp connection, but an induction cooktop may require a connection of 20, 32 or even 42 amps. This must be hard-wired by a licensed electrician (the cost will depend on how difficult it is to install a dedicated circuit between the main power board and the kitchen). Before buying an induction cooktop, we recommend getting a quote for installation costs.

How cheap to run?

The sales talk highlights induction cooktops’ efficiency and cost savings – but when we compared them with a ceramic cooktop they weren’t any cheaper to run over the same period of time.

Because it boils water in seconds, an induction cooktop may save a little energy. But the purchase price is high. And if you don’t have suitable cookware there’s the added expense of new pots and pans.

Our cooktops test and buying guide

Our cooktops test and buying guide

Our cooktops test and buying guide

Induction, ceramic or gas? Find out which type of cooktop will best suit your needs, the features to look for, and compare test results for all 3 types.

Learn more

Member comments

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Graham D.
30 Mar 2019
Buy a separate single induction hotplate.

Bought a Millen single induction hotplate a while ago. Excellent for single person. Don't use the normal hot top any more!

Daniela B.
03 Apr 2019
where can I buy a single induction cooktop from a reputable brand?

I see there is a wide range of cheaper single cooktops on sale (different retailers), but none from Miele or Bosch and I was wondering where we could buy a single induction cooktop that Consumer Institute would recommend? Thanks for your time

Consumer staff
05 Apr 2019
Re: where can I buy a single induction cooktop from a reputable brand?

Hi Daniela,

We recently reviewed two single induction cooktops, and you can find our results here: https://www.consumer.org.nz/articles/breville-the-quick-cook-vs-anko-induction-cooker.

Kind regards,

Natalie - Consumer NZ staff.

Lucy T.
17 Feb 2019
How to tell if oven compatible with induction hob?

We're updating our kitchen and planning to replace our gas hob with an induction hob. Our oven (Westinghouse EW100SD) is about 15 years old but still in good working order so we'd like to retain if possible. How do we tell if our oven is compatible with induction hobs? Do we contact Westinghouse? Or our preferred induction hob manufacturer?

Consumer staff
18 Feb 2019
Re: How to tell if oven compatible with induction hob?

Hi Lucy,

If it’s a built-in oven, you shouldn’t be tied to a specific brand cooktop, even if you originally bought the oven and cooktop as a package. So long as you choose a cooktop that fits the space (allowing for space as recommended by manufacturer) and check with your electrician that it can be installed, it should be fine to replace the old cooktop with an induction hob. The only complication might be if the oven has cooktop controls on it (or vice-versa), but that would probably mean the “oven” is actually a stove. It’s not a bad idea to check with both manufacturers, though.

Kind regards,
Julia - Consumer NZ writer

Donald S.
07 Oct 2018
Interface for Induction Hob

We stayed at a number of EU apartments and the interfaces for activating the hob and then adjusting the temperature were wonderful / intuitive in some cases and really stupid in others. This is one one 'feature' that the potential purchaser needs to carefully consider.. the wrong design will bug you forever

Lucy T.
17 Feb 2019
Please expand!

I'd love to hear which interfaces you found intiutive and which ones were stupid, it would really help with working out what to look for and what to avoid when we (shortly) buy one!

Bridget P.
19 Apr 2018
Just out of warrantee

We moved into a spec house in February 2016. Lovely kitchen including Induction cooktop. We had the correct cookware except for frying pan and stock pot, which we have purchased. Suddenly there was a flash in the middle of one element, and then nothing worked, even the oven was off. Having turned it all off at the wall, we tried to get an electrician. We finally got one around to have a look, he got the oven going again, and was recommended another person who can deal with Smeg. Another week went by before he could come by and have a look. The result is that it cannot be repaired and we will have to get a new one installed at over $2000. I am appalled that such an expensive appliance should last such a little time only 2 years and 2 months.

Marie M.
04 Aug 2017
Had Induction Cooktop for 18 years - Looks like new

Our Bosch Induction cooktop is 18 years old and we have had no problems with it until now, when one pair of elements are no longer working. It still looks as new and it was well used. Will be buying a new on.e

John S.
05 Nov 2016
Would never go back

We have had induction for nearly 6 years and would never go back.
It still looks and works like new.
Very easy to wipe clean (then a quick polish with a hand towel every day)
To avoid scratches, just need to keep bottoms of pots clean - grit will scratch glass.
Power management never a problem - induction is so fast that boost is never needed for long.
Cost of new pots is largely a myth - 100% aluminium will not work, but there is a wide choice of low cost quality cookware suitable for induction, and it is marked as such - you don't need to check with a magnet. And non stick does not need a steel bottom - many have a steel layer inside.
Matching pot to hob size has never ever been a problem for us. We have run our largest pot on the smallest hob and vice versa with no problems, as a trial, but never need to in practice!
Finally, although Consumer may have been unable to observe any power saving compared to ceramic tops, perhaps someone can then explain how it can be that induction is three times faster and also how the ceramic top becomes very hot, without using more power than the induction top.

Kim A.
24 Sep 2016
touch buttons can be difficult for some to use

My parents were recently sold an induction cooktop but have found it quite difficult to work with the touch buttons to swap between elements, change temperature etc. There has been lots of cursing from the kitchen :) Mum also has trouble with arthritis & getting her fingers in the right position to be able to use the panel. Just worth considering when choosing a cooktop - if we had the opportunity again we would definitely choose something easier to use.

David S.
16 Jul 2016
Induction tops best in our experience

This comment facility is really bad. Just spent half an hour writing notes re our experience of induction vs gas. Clicked out to Windows file manager & opened a Word doc to check the actual year we first installed induction cook top (early 2001, so more than 15 yrs ago), came back to finish off the comments only to find everything I had written had disappeared. Sorry, do not have another half hour to spare.

Very briefly, induction much better in our experience - much quicker, safer, including no burns from very hot pot sides and handles, no wasted heat flowing up the sides of pots. So much easier to keep clean (than both gas and radiant ceramic - latter bad when spills burn on at high temperature). Had no problems with scratching but then we use smooth SS cookware, not CI. Heaps of induction ready cookware now available, unlike back in 2001.

Previous member
19 Jul 2016
re: Induction tops best in our experience

Hi David,

We’re sorry about your experience with the comment feature. Your feedback has been passed on to our team to be considered in updates to our website. In future, we’d recommend writing any lengthy comments in a program like Notepad or Microsoft Word first. Apologies for the inconvenience caused.

Thanks for your feedback on both the comment facility and the induction cooktops — we appreciate hearing what our members have to say.

Kind regards,

Fonda
Consumer NZ staff

Laraine B.
30 Jul 2016
David, it stinks when this happens

It's happened to me (but not on Consumer's web site) and like you I didn't have another spare half hour. Induction is the only thing I'd ever desert gas for but alas it's way too expensive. I use SS pots too. When buying these it's important that you make sure they don't just have copper on the bottom. The copper (or aluminium) core should go right up the sides as well. The lids should also be such a good fit that if you turn off the heat and leave the pot for a while the lid won't be easy to get off. Ours have both these features and they are over thirty years old. I stayed with someone who had induction and it certainly made me wish I could have it too. You get clumsy as you get older, and osteoarthritis makes my hands even clumsier. I'm always burning myself, though not with the gas. Well, not yet.

Marcela A.
02 Jul 2016
Induction Hobs: Extremely delicate surface.

I cook at home on a regular basis. I decided to buy an induction hob after carefully researching the market as the safety and electromechanics behind it are sounded.
I have to say that the downfall to the induction surface is the fragile glass surface that gets scratched by regular use. 4 months in my kitchen under my own use the hob has inexplicable marks. I'm careful, I had my cookware replaced and carefully reviewed before putting on the hobs.
I have found no way to repair those hairlines marks except by replacing the glass.

Daniel M.
12 Mar 2016
Some downsides to induction cooktops

Induction cooktops are a huge improvement over radiant-ceramic cooktops. However, there are also several downsides with induction cooktops compared to gas that need to be taken into consideration when deciding the type of cooktop:

- Gas is much more effective if using a wok for cooking. The magnetic field from an induction cooktop only heats the potion of the wok on the cooking surfrace, while gas flames go up the side of a wok.

- Gas cooktops work during powercuts (we found this extremely useful after Christchurch Feb 2011 earthquake when without power for 5 weeks!)

- Gas cooktops with cast iron trivets are much more robust. They can take huge amounts of abuse when tossing food in cast-iron pans which could damage or break a ceramic/glass top.

- Gas cooktops are simple and generally very reliable. Induction cooktops have complex electronics which are more prone to failure.

Laraine B.
30 Jul 2016
You have a point here, Daniel

Persistent power cuts, especially in winter, is the main reason we opted for a stove with a gas hob.

Elizabeth R.
18 Nov 2017
Excellent point

You have an excellent point re induction hobs and power cuts. We counter this with an emergency pack which includes a two burner gas stove and a gas bbq.
I love my induction hob.

Paul & Karen C.
14 Feb 2016
Induction cooktops - eye wateringly expensive to repair

Yes, we love our DeDietrich induction cooktop and then after 7 years the pair of elements on one side died.
I pulled the the cooktop apart and found that the elements were OK but the control board for the pair of elements had a short circuit. I was able to identify the board id.
Now the philosophy of induction cooktop manufacturers for repairs is that it is done on a "whole board" basis. So my assessment from searching De Dietrich parts suppliers in France is that the cost of a new board is around $900 NZ + labour - I then did more Internet searches to find this scale of cost seems comparable across all brands.
So this fact of a likely high cost associated with failures should, I believe, be added to your article on Induction Hobs.
Paul
PS. I analysed the circuitry to find the shortcircuited bits and total cost of these from Element14 is around $50 NZ. However, doing this repair is not for Kiwi bodgers as there are extremely lethal (300V DC) voltages in these boards.

Pamela T.
15 Feb 2017
Yes hugely expensive to repair

My whole Electrolux induction cooktop failed on Christmas Day. Seven years old. Cost to repair $1500 and a 6 week wait for parts.
Installed as per manufacturers specs. - I am now told they have changed the specs. to allow for even more for cooling required under the bench. How long this one will last I don't know - great cooking, easy cleaning BUT ridiculous repair costs.

Anna T.
14 Jun 2017
Far too expensive to repair!!

We've had a Fisher and Paykel induction cook top for 6 years - absolutely love it - except when its not working! An element blew a few years back and was repaired under warranty. Now, just one year out of the 5 year warranty period something has blown again and it's not working. At this stage it looks like its an even bigger problem than last time and the repair man is talking about $1000 in parts to fix it!! Apparently this level of fault is perfectly acceptable according to the lady on the phone and I can't help but feel that it's definitely not ok - seriously not happy!!