How infrared heaters work

Heat that travels like light

An infrared heater warms you the way sunlight does on a cold, clear day. Its element sends out infrared radiation, which mostly passes through the air without heating it and warms the furniture, floors and people it reaches. Source: Health Physics Society

The Department of Energy describes radiant heating the same way: it transfers heat directly from a hot surface to people and objects in the room. A fan heater or oil-filled radiator works by convection instead, warming air that then circulates. Source: DOE

Line of sight matters

Because the heat travels in straight lines, you feel it where the heater can see you. A sofa back, a desk panel or a person standing in the way casts a heat shadow. Aim the heater at the place you sit, not at the middle of an empty room. Source: Far Out editorial

Surfaces that absorb the radiation get warm and give some of that heat back to the room over time. In a small, closed room the air warms up gradually as a result, but the first thing you notice is the warmth on your skin. Source: Far Out editorial

Why the warmth comes and goes quickly

A radiant heater does not need to warm a room full of air before you feel it, so comfort arrives soon after you switch it on. The flip side is that the direct warmth stops soon after you switch it off, because there is no reservoir of warm air or oil behind it. Source: Far Out editorial

That pattern suits short sessions in one spot: a garage workbench, a reading chair, a desk. For steady warmth across a closed room for many hours, a convection heater or the home's main heating system may suit better. Source: Far Out editorial

Glowing elements and quiet panels

The hotter an element runs, the more it glows. Quartz and halogen tubes give off visible orange light along with their heat, while low temperature panels and many carbon elements give off little or no light. Our heater types guide compares them. Source: Far Out editorial

The National Fire Protection Association's space heater tip sheet describes the category in one line: in infrared heaters, heat is created by infrared bulbs. Panel models use flat elements instead of bulbs, but the principle is the same. Source: NFPA

Is infrared radiation harmful?

The Health Physics Society, a professional body for radiation safety, says infrared heaters used indoors or outdoors are safe, especially when the appropriate safety factors are considered. It notes that heater radiation is much different from the radiation associated with x-ray machines or germicidal lightbulbs. Source: Health Physics Society

The same answer names the real risks. Extreme heating of materials or skin can cause fires or burns, and staring at a heater for a long time can overheat the eye. Keep a sensible distance, do not watch the element and keep combustibles clear. Source: Health Physics Society

Do infrared heaters dry out the air?

A radiant heater warms surfaces rather than blowing heated air, so it does not move air the way a fan heater does. It does not add or remove moisture either. Indoor air in winter can feel dry for many reasons, and a heater of any kind will not fix that. Source: Far Out editorial

Do infrared heaters work outdoors?

Yes, for people within range. Because the heat reaches you without warming the air first, a radiant heater can warm a seating area on a covered patio where a fan heater's warm air would blow away. Electric outdoor models need an outdoor listing; see our patio guide. Source: Far Out editorial