Induction Heating (IH) Cookers

IH cookers are appliances that heat food using only electricity, without the need for gas or fire. Using a technology called Induction Heating (IH), these cookers offer several advantages, such as avoiding polluting indoor air pollution and reducing fire hazards.
While many people think of stovetop IH cookers, other appliances using the same heating principle, such as IH rice cookers, are also available.

Types of IH Cookers

Stovetop IH cookers come in two types: "Iron & Stainless Steel Heating" and "All-Metal Heating." The "All-Metal Heating" type can accommodate various metals, and therefore, uses a higher frequency magnetic field compared to the "Iron & Stainless Steel Heating" type.

Induction Heating Mechanism

When an intermediate-frequency alternating current (20 kHz to 90 kHz) flows through the coil placed under the top plate of an IH cooker, magnetic field lines are generated from the center of the coil. These magnetic field lines induce eddy currents at the bottom of metal pots and pans, causing the cookware itself to heat up due to its electrical resistance, thereby heating the contents.

Values of Magnetic Flux Density Generated by IH Cookers

The reference level for general public exposure to 20 kHz - 90 kHz magnetic fields, as recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) is 27 µT (microtesla).
The Japan EMF Information Center (JEIC) measured the magnetic field density (MFD) from three types of household IH appliances—stovetop IH cookers, portable IH cookers, and IH rice cookers— in accordance with the guidelines outlined in IEC 62233. All the measured values of MFD were found to be below the reference levels recommended by the ICNIRP.

Health Effects of Magnetic Fields from IH Cookers

Scientifically established effects on human body (short-term exposure effects): When the human body is exposed to very strong magnetic fields, more than a thousand times stronger than those generated by IH cookers, the phenomenon known as electromagnetic induction can affect nerve and muscle activity. Even stronger magnetic fields can impact heart function.

Scientifically unestablished effects on human body (long-term exposure effects): Research on the health effects of intermediate frequency electromagnetic fields used in IH cookers is limited compared to low-frequency and radio-frequency electromagnetic fields. While more research is needed, no scientific evidence currently indicates any health effects. Studies in Japan have examined whether IH cookers cause miscarriage, preterm birth, or fetal malformations, or have carcinogenic effects, but none have found any negative impacts on pregnant women or fetuses.
For more details, click here:
[Ministry of Health, Labour and Welfare Science Research Database] Research on Intermediate Frequency Electromagnetic Fields in Residential Areas [only in Japanese]
Maternal Use of Induction Heating Cookers During Pregnancy and Birth Outcomes: The Kyushu Okinawa Maternal and Child Health Study
[Central Research Institute of Electric Power Industry] Carcinogenicity of intermediate frequency magnetic field in Tg.rasH2 mice

For Those Concerned About Using IH Cookers

The magnetic field leakage from IH cookers can increase if small pots are used or if pots are not centered on the heater. However, following the manufacturer’s recommended pot sizes and usage guidelines can minimize leakage. For those who are still concerned those still concerned about electromagnetic fields, it is important to read the instruction manual carefully and use the appliance correctly.
The Swiss Federal Office of Public Health (FOPH) has published an EMF Fact Sheet on Induction Heating Cookers with guidelines to minimize unnecessary exposure to magnetic fields. Here are some recommendations:
− Make sure that you have read and understood the operating and safety instructions in the operating manual and follow these correctly.
− Use the right size of cookware for the size of the cooking zone marked out on the glass ceramic surface; don't put a small pan on a large zone, but use a pan that covers the cooking zone completely. Always place the pan in the middle of the cooking zone.
− Don't use damaged pans with buckled or rounded bases, even if they can still be heated without difficulty.
− Persons standing close to the hob or who touch the worktop with their body during cooking are advised to use the rear cooking fields, or the front cooking fields at reduced power.
− Exposure to magnetic fields can be reduced greatly by keeping a distance of 5-10 cm between your body and the hob.
− It is vital to use specially manufactured pans to ensure that energy is transmitted efficiently from the hob to the pan. They are labelled by the manufacturer as suitable for induction cooking.
− People with a cardiac pacemaker or an implanted defibrillator should talk to their doctor before using an induction hob. To prevent leakage currents from flowing through your body which could possibly interfere with these devices don't use metal cooking spoons.

Regulatory

In Japan, the radio frequency electromagnetic fields emitted by IH cookers is regulated by the "Radio Law Enforcement Regulations."

For more details, click here.