A combination heating system and method, including a combustion chamber, a combustion heat exchanger receiving heat from the combustion chamber, and a thermal storage reservoir. The combustion heat exchanger includes first fins extending outward from the combustion heat exchanger, and at least some of the first fins may have a profile that is at least partially curved or S-shaped. The thermal storage reservoir has an outer wall and an inner wall, and may contain a fluid such as glycol between the outer wall and the inner wall. The inner wall forms a hollow passageway through which the combustion heat exchanger extends. The thermal storage reservoir also includes second fins extending inward from the inner wall toward the combustion heat exchanger. The first fins interdigitate with the second fins in a spaced-apart manner such that airgaps exist between adjacent interdigitated ones of the first fins and the second fins.

Example embodiments relate to a device for heating air and a liquid. A control unit controls an air conveying device and a liquid conveying device depending on whether the device heats only air in an air mode or liquid in a different mode.

Example embodiments relate to a device for heating air and a liquid. A control unit controls an air conveying device and a liquid conveying device depending on whether the device heats only air in an air mode or liquid in a different mode.

Disclosed is an air heating apparatus including an expansion tank that preserves water, a water heater that receives heat from a combustion gas generated through a combustion reaction to heat the water, a heating heat exchanger that receives the water heated by the water heater and exchange heat with air that is to be discharged for heating, a fan that sends the air to the heating heat exchanger, a circulation supply passage that connects the expansion tank, the water heater, and the heating heat exchanger to guide the water in the expansion tank to the heating heat exchanger via the water heater, a circulation recovery passage formed to connect the heating heat exchanger and the expansion tank to guide the water that exchanged heat with the air to the expansion tank, and a hot water heating passage.

Disclosed is an air heating apparatus including an expansion tank that preserves water, a water heater that receives heat from a combustion gas generated through a combustion reaction to heat the water, a heating heat exchanger that receives the water heated by the water heater and exchange heat with air that is to be discharged for heating, a fan that sends the air to the heating heat exchanger, a circulation supply passage that connects the expansion tank, the water heater, and the heating heat exchanger to guide the water in the expansion tank to the heating heat exchanger via the water heater, a circulation recovery passage formed to connect the heating heat exchanger and the expansion tank to guide the water that exchanged heat with the air to the expansion tank, and a hot water heating passage.