Induction vs radiant electric cooktops

Cooking with electricity has advantages over gas, including better safety and cooking performance. In particular, electric cooktops are superior to gas when it comes to indoor air quality. Induction cooktops also transfer energy more efficiently and will boil a pot of water faster than any other technology.

However, not all electric cooktops are the same. Electric coil cooktops, which have been around for more than a century, are reliable and usually the least expensive option, but they have disadvantages such as slow response to temperature changes and mediocre energy efficiency.

A sleeker-looking upgrade to electric coil burners is a glass-ceramic electric cooktop, also known as a smooth top. If you go to the appliance store, you might have trouble telling them apart from induction cooktops, which also have smooth glass-ceramic surfaces. However, there’s a big difference in cooking performance and energy efficiency.

That doesn’t mean that induction is always the best choice for homeowners. This article will explain the pros and cons of induction and smooth top radiant cooktops to help you decide what’s best for your kitchen.

All about radiant and induction glass-ceramic cooktops

Radiant and induction cooktops look similar. They both use smooth glass-ceramic surfaces that cover all the elements of the cooktop and have lines that mark the location of the elements.

Glass-ceramic is stronger and can tolerate temperature changes better than conventional glass. Glass-ceramic cooktops can easily handle the weight of heavy pots, but they aren’t indestructible. They can be shattered by impacts, such as dropping a heavy pot onto the surface. And while they are scratch-resistant, they aren’t scratch-proof. Dragging a cast iron pan across a glass-ceramic surface can scratch it.

And while they are designed to handle high heat, rapid temperature changes can also shatter glass-ceramic cooktops. For example, don’t place a very hot pan onto a cold cooktop.

Advantages glass-ceramic are that it looks great and is easy to clean. If you have gas or electric coil burners, you know how annoying it is to clean up spills. In contrast, you can just wipe spills off a radiant or induction cooktop.

What is a radiant electric burner?

Radiant electric cooktops have elements that generate heat that causes the glass-ceramic surface above to heat up. The cooktop is also partially transparent, allowing some infrared energy to pass through directly.

The element underneath the glass operates on electric resistance, the same as a conventional electric coil: electricity passes through the element, causing it to heat up. The difference between an electric coil and a radiant element is the thickness of the wire. While an electric coil needs to be thick enough to directly handle the weight and physical impact of pots and pans, radiant elements are protected by the glass above. This means that the elements can be made much thinner, which allows them to respond quickly when you switch on the power.

This causes the elements to glow bright red when they’re switched on. In fact, these are sometimes called halogen elements because they operate similar to a halogen incandescent light bulb.

Faster response time, easier cleaning, and a sleek appearance are the key benefits of radiant cooktops over conventional electric coils.

One disadvantage is that radiant elements have a limited lifespan - up to 4,000 hours according to some manufacturers. This means that you should be prepared to replace an element if you plan to keep your cooktop for a long time. (It’s possible to do this yourself if you can find the correct replacement part.)

What is a magnetic induction cooktop?

A magnetic induction cooktop operates on an entirely different principle from electric resistance-based radiant and coil elements. Instead of generating heat directly, induction cooking uses magnetic fields to induce what are known as eddy currents in metallic cookware. An eddy current is a closed loop of electric current¹. Electrical resistance in the metal cookware causes it to heat up in the same way as the wire in a light bulb or cooking element.

In other words, electric resistance is also responsible for producing the heat in induction cooking. The difference is that it happens in the cookware directly rather than in a heating element.

The cookware needs to be made of a material that is ferromagnetic, which means that it can be attracted to a magnet. This includes cast iron, enameled cast iron, carbon steel, and some types of stainless steel. In general, 18/0 stainless steel is induction-compatible, but 18/10 and 18/8 are not. Look for the induction symbol on the bottom of the pan to be certain.

This difference in the way induction works means that the glass surface of the cooktop doesn’t heat directly and will only get hot from contact with the pan above. This cooler temperature is a big safety advantage, but there are other advantages too. You can learn more in my introductory article on induction cooking.

Key differences between induction and radiant electric cooktops

I mentioned at the start of this article that induction cooking has significant advantages over older radiant technology. While this is true, there’s a couple reasons why someone might choose to go with radiant. The main reasons are lower cost and compatibility with more cookware.

Advantages of radiant cooktops:

• Lower cost (roughly 33% less than an equivalent induction model)
• Works with a wider variety of cookware
• More models available (for now)
  
  

Cost is maybe the most obvious advantage of radiant cooktops. In general, radiant cooktops will cost less than an induction cooktop with the same size and number of burners. After researching induction and radiant models from the same manufacturer on the Lowe’s website, I found that you can expect to pay very roughly 1/3 less for a radiant model.

That said, both radiant and induction cooktops are available in high and low end models, so it is possible to find low cost induction cooktops – something that wasn’t possible a few years ago.

Radiant cooktops also don’t require magnetic cookware, so if you have a large collection of copper, aluminum or incompatible stainless steel cookware, a radiant cooktop won’t require you to purchase new pots and pans.

Finally, you’ll find more choice with non-induction cooktops, although that is changing rapidly as induction is becoming more popular.

Advantages of induction cooktops:

• Much better cooking performance
• Higher energy efficiency
• Multiple safety features
• Sensor-based temperature control
  
  

Radiant cooktops win on lower upfront cost and avoiding the need to invest in new cookware, but induction is far superior when it comes to cooking. Induction even outperforms gas cooktops, which for long have been the standard for cooking performance. Power output varies, but you can expect an induction burner to boil a pot of water in half the time of a gas or conventional electric burner.

Not only that, but induction cooktops respond instantly when you adjust the power output, which traditionally has been a main advantage of gas cooking. When you cut the power to an induction cooktop, the heat input stops immediately, unlike a conventional electric burner which stays hot for several minutes.

Health and safety features are also reasons to choose induction. Indoor air pollution from gas stoves is a particular problem. For example, gas stoves are implicated in a significant percentage of childhood asthma cases.

Induction cooktops also have sensors that provide safety features that other cooking technologies can’t. For example, if you forget a pot on an induction stove and let it boil dry, a temperature sensor will detect when the pot has exceeded a safe temperature and will automatically turn off the element. If like me you’ve ever had to worry about elderly family living alone, this is a great feature.

Temperature sensors also enable induction cooktops to automatically hold a pot at set temperature. This makes it a lot easier if, for example, you want to simmer a pasta sauce for a long time without burning it. Just set a low temperature, and the cooktop will automatically adjust the power output to keep it steady.

Finally, there’s no issue with an induction cooktop about forgetting to turn off a burner. If there’s no cookware present on an element that is turned on, the cooktop will sense this and turn the element off. No more worrying about whether you left your cooktop on before going on vacation!

Radiant, gas, and induction energy efficiency compared

One big advantage of induction cooking is that it is more efficient than either gas or conventional electric cooking.

According to one study², the average efficiency of gas, conventional electric, and induction cooktops was 28%, 39% and 70%, respectively. Efficiency means the amount of energy that is transferred to the cookware rather than being lost to the air or otherwise wasted by the cooktop.

The study also examines the effect of cookware size on cooking efficiency. If a pot is too small for the cooking element – especially with gas and conventional electric – heat will be lost up the sides of the pot. This is less of an issue with induction cooking. In the study, the maximum efficiency achieved by gas, conventional electric, and induction was 35.5%, 51.8%, and 81.3% respectively.

Better energy efficiency is a great feature for saving money, but it is also the reason why induction cooktops are able to boil a pot of water much more quickly than other types.

Power output and electrical requirements of radiant and induction cooktops

Radiant and induction ranges generally require a 240-volt circuit with 30 to 50 amps of power. This means that if you already have an electric range, you can likely upgrade to an induction model without needing to upgrade your electrical.

If you choose a cooktop (that is just a cooking surface without an oven), the power requirements will be lower - generally 30 amps or less.

You can even get started with a single element induction cooktop that plugs into a standard 120-volt outlet.

The maximum power output of radiant elements varies from as little as 800 watts for small simmer elements up to 4,800 watts. Induction ranges can put out even more power - I found a high end model with a 5,500 watt element. Combined with the high efficiency of induction cooking, this level of power output will let you bring even a large stock pot full of water up to a boil very quickly.

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