2022-12-27 · Replacing an HVAC system costs $5,000 to $11,000, including a new central air conditioner unit and a new gas furnace. Furnace replacement costs $2,000 to $5,400 on average, depending on the system size, efficiency, brand, and fuel type. Installing a heat pump costs $3,800 to $8,200, depending on the type, size, brand, and efficiency rating.