Do Infrared Saunas Use Microwaves? Infrared vs. Microwaves

Short answer

No. Infrared saunas use heaters that give off infrared radiation, with wavelengths from 780 nanometers to 1 millimeter. Microwave ovens use waves about 12 cm long that make water molecules in food vibrate. Both are non-ionizing radiation, so neither has enough energy to knock electrons out of atoms. With both, the main known risk is too much heat.

Infrared saunas and microwave ovens both use electromagnetic radiation to make things warm, so it is easy to mix them up. They are different technologies with different wavelengths, and they heat in different ways. Here is what official science and safety sources say.

Table of Contents

Infrared vs. microwaves at a glance

Infrared saunas vs. microwave ovens (sources checked 21.10.2026)
	Infrared sauna	Microwave oven
Type of radiation	Infrared (780 nm to 1 mm)	Microwaves, part of the radio-frequency range (100 kHz to 300 GHz)
Typical wavelength	Nanometers to micrometers (for example, heat lamps 500 to 3,000 nm)	About 12 cm
Source	Carbon or ceramic panels, rods or filtered lamps	Magnetron (an electron tube)
How it heats	Radiant heat absorbed by the skin	Makes water molecules in food vibrate
Ionizing?	No	No
Main known risk	Thermal injury to skin and eyes, heat stress	Heating of tissue (burns) at high levels

Sources: ICNIRP: Infrared, ICNIRP: RF EMF, NASA: Infrared waves, NASA: Microwaves and FDA: Microwave oven radiation.

How microwave ovens create heat

The FDA explains that a device called a magnetron inside the oven produces microwaves. They bounce off the metal walls and are absorbed by food, where they make water molecules vibrate. That vibration produces heat. NASA adds that ovens use microwaves about 12 cm long. Microwaves are reflected by metal and pass through glass, paper and most plastics, which is why food goes into those containers.

The FDA also clears up two myths. Microwave ovens do not cook from the inside out: the outer layers heat first and the inside cooks mostly by conduction. And microwaved food does not become radioactive. A federal standard limits leakage over an oven’s lifetime to 5 milliwatts per square centimeter at about 2 inches from the surface, which the FDA calls far below the level known to harm people.

How infrared heat works

ICNIRP defines infrared radiation, also known as thermal radiation, as the band of the spectrum just beyond visible red light, from 780 nm to 1 mm. It splits it into IR-A (780 nm to 1.4 µm), IR-B (1.4 to 3 µm) and IR-C or far-infrared (3 µm to 1 mm). The sun and fire are natural sources. NASA notes that we cannot see infrared, but we feel it as heat, and that heat lamps often emit at 500 to 3,000 nm.

Infrared does not need to heat the air first. It is absorbed by whatever it reaches, including your skin. How deep it goes depends on the wavelength: ICNIRP says IR-A penetrates skin to several millimeters, while IR-C is absorbed at the surface.

How an infrared sauna is heated

ICNIRP describes three main types of infrared cabin. Two emit almost only far-infrared (IR-C): large, low-temperature wall panels (surface about 50 to 70°C), or ceramic or metal rods (about 300 to 400°C) with reflectors. A third type uses filtered lamps that emit IR-A or IR-B and a little visible light. The cabin air stays around 40°C, compared with 85 to 90°C in a traditional sauna. For panel types, see infrared sauna types and ceramic vs. carbon heaters; for real temperatures, see how hot infrared saunas get.

You will often read that infrared heats you “from the inside out”. ICNIRP says the opposite for far-infrared: it is completely absorbed in the most superficial layers of the skin, which is why skin can get hotter and stay red for a while.

Is infrared more harmful than microwaves?

Higher frequency means more energy per photon, and infrared does have a higher frequency than microwaves. But both are non-ionizing. NASA and the FDA explain that only ionizing radiation, such as X-rays, gamma rays and some ultraviolet, has enough energy to knock electrons out of atoms and damage cells that way.

For both, the known risks come from heat. ICNIRP says that after decades of research the only substantiated health effect of radio-frequency fields is heating of tissue, and the FDA notes that high microwave levels can cause burns or cataracts. For infrared, ICNIRP says harmful effects are due to thermal injury, mainly of the eyes and skin. It also states that infrared is not thought to play a role in starting skin cancer.

In 2011, the WHO’s cancer agency IARC classified radio-frequency electromagnetic fields as “possibly carcinogenic to humans” (Group 2B). That rating is based on limited evidence of an increased risk of glioma linked to wireless phone use. It concerns radio-frequency fields, not infrared.

Using an infrared sauna sensibly

ICNIRP gives practical advice for infrared cabins:

People at risk from overheating, such as those with cardiovascular disease, should get medical advice before use.
Anyone whose sense of heat or pain is reduced by medication, drugs or alcohol should limit exposure.
Avoid infrared cabins and lamps within 24 hours of intense sun or UV exposure.
If skin redness lasts more than a day, or color changes persist, stop and get medical advice.

ICNIRP also says the scientific evidence for the claimed health benefits of infrared cabins is currently limited. Read more in can infrared saunas be dangerous, can an infrared sauna burn your skin and can an infrared sauna hurt your eyes.

What about EMF from infrared saunas?

EMF is a separate topic from microwaves. Infrared saunas run on mains electricity. ICNIRP explains that people are exposed to low-frequency (50 or 60 Hz) electric and magnetic fields around electric appliances, mostly at home and at work, and an infrared sauna is one such appliance. Some brands advertise low-EMF heaters. We explain what that means in are Dynamic saunas low EMF.

Frequently asked questions

Do infrared saunas use microwaves?

No. Infrared saunas use carbon or ceramic panels, rods or lamps that give off infrared radiation. Microwave ovens use a magnetron, an electron tube that makes microwaves. The two sit in different parts of the electromagnetic spectrum.

What is the difference between infrared and microwaves?

Wavelength. ICNIRP defines infrared as 780 nm to 1 mm. Microwaves are longer; NASA says microwave ovens use waves about 12 cm long. Microwaves are part of the radio-frequency range, which ICNIRP defines as 100 kHz to 300 GHz.

Is infrared radiation more harmful than microwaves?

Not in the way the question usually means. Both are non-ionizing. ICNIRP says the harmful effects of infrared come from thermal injury, mainly to the eyes and skin, and that the only substantiated health effect of radio-frequency fields, including microwaves, is heating of tissue.

Does an infrared sauna heat you from the inside out?

Not really. ICNIRP says far-infrared, the type most cabins use, is absorbed completely in the outermost layers of the skin. Near-infrared (IR-A) reaches several millimeters. Even microwave ovens do not cook from the inside out, according to the FDA.

Are microwaves classified as possibly carcinogenic?

In 2011 the WHO’s cancer agency IARC classified radio-frequency electromagnetic fields as possibly carcinogenic to humans (Group 2B), based on an increased risk of glioma linked to wireless phone use. Infrared is a different part of the spectrum, and ICNIRP says infrared is not thought to play a role in starting skin cancer.

Do infrared saunas give off EMF?

Infrared saunas are electrical appliances, and ICNIRP notes that people are exposed to low-frequency (50 or 60 Hz) electric and magnetic fields around electric appliances. Some brands sell low-EMF heaters. That is a separate question from microwaves; see our guide to low-EMF saunas.

Sources

This guide is based on the linked NASA, FDA, ICNIRP and IARC sources, checked on October 21, 2026. We did not take any measurements ourselves. It explains the physics and does not give medical advice.