Yes, a gas furnace is a type of HVAC system. A gas furnace, specifically, falls under the heating component of HVAC. It works by burning natural gas to produce heat, which is then distributed throughout a building via a network of ducts and vents. This makes it an integral part of many HVAC systems, particularly in regions where cold weather demands efficient, powerful heating solutions.

An HVAC gas furnace works by drawing in cold air from the room, cleaning it through an air filter, and then heating it using a gas burner and a heat exchanger. The burner ignites the gas, creating heat, which is transferred to the air within the heat exchanger. This heated air is then circulated throughout the building via a system of ducts by a blower motor.

The exhaust gases produced in the combustion process are safely vented out of the building through a flue or chimney. The furnace's operation is regulated by a thermostat, which ensures that the indoor temperature remains at the desired level, turning the furnace on and off as needed.

A gas furnace typically lasts between 15 to 20 years, though this lifespan can vary based on the furnace's make, model, and overall quality, as well as how well it is maintained. Regular maintenance, such as cleaning and replacing filters, checking and cleaning burners, and ensuring the thermostat and other controls are functioning properly, can significantly extend a furnace's life.

Environmental factors and usage patterns also play a role; for instance, a furnace in a region with long, harsh winters may have a shorter lifespan due to more intensive use. Upgrading to a newer, more efficient model might be cost-effective even before the end of the furnace's operational life, considering advancements in technology and energy efficiency.