Heat pump reversing valve
The reversing valve is the part that makes a heat pump a heat pump — it flips the refrigerant flow between heating and cooling.
What the reversing valve does
The reversing valve is a brass component near the compressor in the outdoor unit. An electric solenoid shifts it to change the direction of refrigerant flow, switching the system between heating and cooling. It is the single part that separates a heat pump from a plain air conditioner.
Signs of a stuck or failed valve
- Stuck in cooling — blows cold air even when set to heat.
- Stuck in heating — blows warm air when set to cool.
- Won't switch modes at all, or switches randomly.
- A loud "whoosh" is normal when it shifts; grinding or no shift is not.
A failing solenoid coil (cheaper) can mimic a failed valve (pricier), so a technician should diagnose which it is.
Repair cost
Replacing a reversing valve typically runs $600–$1,300 including labor and refrigerant recovery/recharge — it is a sealed-system repair requiring an EPA-certified tech. Just the solenoid coil is far cheaper. On an old, out-of-warranty unit, weigh the repair against replacement. More on repair costs.
Frequently asked questions
What does a reversing valve do in a heat pump?
It changes the direction of refrigerant flow to switch the system between heating and cooling — the part that makes a heat pump able to do both.
How much does it cost to replace a reversing valve?
Typically $600–$1,300 including labor and refrigerant work; replacing just the solenoid coil is much cheaper.
Can a stuck reversing valve be fixed?
Sometimes the issue is just the solenoid coil, which is inexpensive. A truly failed valve needs sealed-system replacement by a certified technician.
Related
Sources & further reading
Educational guide, reviewed against US DOE & ENERGY STAR guidance and updated June 2026. Estimates only — not a substitute for a professional assessment or Manual J load calculation.