A residential HVAC system is a combination of heating, ventilation, and air conditioning systems designed to provide comfortable indoor temperatures and air quality in a home. The system typically consists of a furnace, air conditioner, and air handler, as well as ductwork and other components. The furnace is responsible for heating the air, while the air conditioner cools it. The air handler circulates the air throughout the home, and the ductwork distributes the air to each room. The system is designed to maintain a comfortable temperature and humidity level, as well as filter out airborne particles and pollutants.