An air heater is provided for use in buildings or other structures. The air heater uses infrared lamps to generate a temperature rise in a forced air chamber that contains several infrared lamps, in which two ends of the chamber act as an inlet and an outlet, and in which the chamber has a highly reflective interior surface that reflects the light being emitted by the lamps to multiply the thermal effect of the infrared light sources. An alternative embodiment uses a closed chamber, in which the temperature rise causes the unit to act as a detonator.