Induction cooktops heat pans directly via electromagnetic fields, not the surface.
- You need ferromagnetic cookware like cast iron or magnetic stainless steel.
- Induction is more energy-efficient and faster than gas or radiant electric.
- Safety benefits include cool surfaces and auto shut-off, but installation requires a 240-volt circuit.
What is induction cooking?
Induction cooking uses electromagnetism to heat cookware directly. A copper coil sits under a ceramic glass surface. When you turn on a burner, alternating current flows through the coil. That creates a rapidly changing magnetic field. The field passes through the glass and hits the pan's ferromagnetic base. It induces swirling electric currents, called eddy currents, inside the metal. These currents generate heat from electrical resistance. The pan heats up, but the cooktop surface stays cool to the touch.
How does the magnetic field generate heat?
The magnetic field oscillates at a high frequency, typically between 20 and 100 kHz. That oscillation makes the magnetic domains in the pan flip rapidly. Flipping domains cause friction at the molecular level, producing heat. Additionally, eddy currents flow in loops within the pan's base. Resistance to those currents converts electrical energy into thermal energy. Both effects work together to heat the pan quickly. The heat transfers to food through the pan's surface. No flame or radiant element is involved.
What cookware works with induction cooktops?
Induction requires ferromagnetic cookware, meaning it must contain iron. Cast iron, enameled cast iron, and most stainless steel with a magnetic base work. To test, hold a magnet to the bottom of a pan. If it sticks firmly, the pan is compatible. Aluminum, copper, and glass do not work unless they have a magnetic layer bonded to the base. Many modern pans now include an induction-ready disc. Check the product label for an induction symbol or the word 'induction.'
How efficient are induction cooktops compared to gas or electric?
Induction is about 84 to 90 percent energy efficient, according to the U.S. Department of Energy. That means most of the electricity becomes heat in the pan. Radiant electric cooktops achieve only about 74 percent efficiency. Gas is even lower, around 40 percent, because heat escapes around the pan. Induction also heats faster because energy goes directly into the metal. Boiling water can take half the time of gas. Over a year, that efficiency can lower your energy bill.
What are the safety benefits and limitations of induction?
The cooktop surface stays cool, reducing burn risk. It also shuts off automatically if no pan is detected. There are no open flames or hot coils, so fire risk drops. However, induction requires a dedicated 240-volt circuit in most homes. Some models need special installation, which adds cost. The glass surface can scratch if you slide heavy pans. Also, induction can interfere with pacemakers, so check with your doctor if you have one.