The object) aimed at in the improvements, is to obtain as much caloric as possible from the furnace ... air passes, and by fixing outside the same air chambers or drums, through which the hot ...

Gas and oil furnaces burn fuel to provide heat for homes ... which typically consists of an array of metal tubes. Hot air from the primary exchanger cools and condenses when it enters the tubes ...

Although some furnaces generate heat through electricity, or by burning wood, coal or oil, they most commonly burn natural gas or liquid propane gas (LPG). If you own a gas-burning forced-air ...

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