How to Integrate a Heat Pump with an Existing Gas Furnace
Published: July 20, 2026 — BC Wide Home Services Ltd, doing business as BC Wide Heating & Air Conditioning — Greater Vancouver, BC
System Components
A dual-fuel system requires: outdoor heat pump, indoor evaporator coil (installed above the furnace), a transition box (if needed for duct connection), a dual-fuel thermostat (Ecobee, Nest, or manufacturer-specific), and a control board that manages the changeover between heat pump and furnace.
Installation Cost
Adding a heat pump to an existing gas furnace costs $6,000-10,000 (heat pump, coil, controls, installation). If the furnace also needs replacement, total cost is $10,000-18,000. CleanBC rebates of $2,000-4,000 apply to the heat pump portion.
Changeover Logic
The thermostat decides which heat source to use based on: outdoor temperature (setpoint), indoor temperature versus setpoint difference (large difference = furnace), and time to recover from setback. Most systems prioritize the heat pump and only use the furnace when needed.