Electric induction cooktops use a magnetic field to heat cookware rather than the cooking surface itself. This magnetic field is harmless and imperceptible -- unless you put a metal pan on the burner. When that happens, the magnetic field reacts with iron molecules in the pan, exciting them and generating heat. The stronger the magnetic field, the hotter the pan gets and the faster food cooks.
Because heat transfers directly, induction cooktops are nearly twice as energy efficient as gas, smoothtop or electric coil cooktops, meaning they heat up in far less time. They're also safer. If a child accidentally moves a pan, the pan heat immediately decreases, and the elements themselves stay much cooler than a traditional electric or gas burner.
Still, there are a few drawbacks. For starters, some users say their induction cooktops make a slight humming sound when in use. More importantly, induction cooktops require magnetic cookware to work. Cast iron and most kinds of stainless steel are okay, but not copper, glass, ceramic or aluminum. These cooktops are also more expensive on average than other types, starting at around $1,200 -- about what you'd pay for a top-of-the-line electric smoothtop.
In professional testing, the GE Profile PHP900DMBB (*Est. $1,480) earns outstanding marks for its performance on both high- and low-heat settings. This 30-inch induction cooktop is made of black ceramic glass and is available with or without a stainless-steel frame. Its four induction burners range in size from 6 to 11 inches and in power from 1,800 to 3,700 watts, and each has 19 power settings for precise temperature control. Other features include touchpad controls with a child lockout, hot-surface lights for each burner and a sensor that automatically adjusts the heating element to the correct pan size. The cooktop comes with a one-year warranty.
We found about 50 user reviews of the GE Profile PHP900DMBB at Buzzillions.com and Amazon.com. Owners are enthusiastic about this cooktop's fast heating, superb temperature control and easy cleanup. They also appreciate the stay-cool induction burners; one user from Texas says they make a tremendous difference in kitchen temperature and the induction cooktop will pay for itself in reduced cooling costs. Most users find the touchpad controls easy to use.
A few users mention a buzzing or humming noise when the cooktop is in use, while others grumble about the need for ferrous (magnetic) cookware. The most serious complaints were related to durability. One user says the cooktop scratches easily, even with careful use. Two others report that their cooktops broke down one to three years after purchase, requiring repairs that would have cost more than replacing the entire cooktop.
The Kenmore 43800 (*Est. $1,520) also performs very well in professional tests, with overall scores nearly as high as the GE Profile's. This 30-inch induction cooktop is made of black ceramic glass with a stainless-steel frame and electronic touch controls. It has four heating elements ranging in size from 6 to 10 inches, each with 15 heat settings. Each burner automatically senses the presence of magnetic cookware and adjusts its size accordingly. Other features include hot-surface indicators, a control lockout, an automatic shutoff and a warming setting that lets you hold cooked food at the temperature you want. The Kenmore cooktop has a one-year warranty.
Reviews for the Kenmore 43800 are scarce. We found a couple at Sears.com, the only retail site that sells Kenmore appliances. These reviewers are very pleased with the induction cooktop's surface, although one warns that it's an exaggeration to say that it stays cool to the touch. The cooktop's fast, responsive heating is also cited as a plus, and one user was pleased that the new cooktop provided an excuse to replace old cookware.
The Bosch NIT5065UC (*Est. $2,000) also scores highly in independent tests; like other recommended induction cooktops, it gets excellent scores for both high and low heat performance. Like the Kenmore, this 30-inch cooktop has a black ceramic surface with stainless-steel trim and electronic touch controls. Its four burners range from 6 to 11 inches; like other induction cooktops, this one will automatically adjust burner size to fit your cookware. Burner power ranges from 1,800 to 3,600 watts, and each burner has 17 power settings. Other features include a child lock, a hot-surface indicator, a separate timer for each burner and an overflow detection feature that shuts off the cooktop in the event of a major spill. The cooktop is covered by a one-year limited warranty.
Like most induction cooktops, the Bosch has not received many reviews from users. We were able to scrape together only a handful of reviews from retail sites AJMadison.com and ABT.com. All reviewers give this cooktop 5 stars, praising its responsiveness, fast heating and easy installation. However, two users, though delighted with their new cooktops, mention durability problems; one warns that the surface can be scratched by pans sliding back and forth, and another says that "our granite installers" cracked the cooktop, presumably while installing new counters. Even though both these users still award the cooktop 5-star ratings, two durability problems out of three reviews isn't the most impressive record.