Heaters are devices that generate and distribute heat to maintain a comfortable indoor temperature, especially during colder weather. They can be part of a central system, like a furnace or boiler, or individual units like space heaters for localized heating. Heaters work by adding thermal energy to the air, often using electricity, gas, or other fuels.

The Evaporator coil is a key component located inside the indoor unit that absorbs heat from the air, cooling it before it's circulated back into the space. It works by using refrigerant, which evaporates as it absorbs heat, causing the air passing over the coil to cool down.