Abstract: A heater which is preferably rated at about 1,500 watts is described. This heater contains at least three separate heat exchangers; each of the heat exchangers contains heat exchanger tubes, and each of the heat exchangers contains a different fluid capacity.A blower passes cold air, in sequence, past the first heat exchanger, then past the second heat exchanger, and then past the third heat exchanger. At the same time, a pump forces a heated heat-exchange medium through the third heat exchanger, through the second heat exchanger, and then through the first heat exchanger.