Heat Pump Making Noise? What's Normal in Durham Region and What Isn't
Written by Zack Laundrie | Licensed HVAC Technician, Durham Region | Published on March 12, 2026
Your heat pump has been running fine all winter, and then one morning it starts making a sound you haven’t heard before. Maybe it’s a low hum that seems louder than usual, a clicking at startup, or something closer to a rattle or bang. The question most Durham Region homeowners ask next is the same one: is that normal, or do I need to call someone?
The honest answer is that heat pumps are not silent machines, and not every unfamiliar sound is a red flag. But a few specific sounds do mean the system needs attention before a small issue turns into a costly repair. This guide walks through the sounds you will actually hear from a properly running heat pump, and the ones that should put you on the phone with an HVAC technician.
Sounds a Healthy Heat Pump Makes
Understanding baseline heat pump noise in Durham Region starts with knowing what these systems do. A heat pump moves refrigerant between an outdoor unit and an indoor air handler, runs a fan in both locations, and cycles a compressor on and off as demand changes. Each of those actions produces sound.
Steady Low Hum
The outdoor unit’s fan and compressor create a continuous hum during operation. Most cold-climate heat pumps installed across Durham Region today run at 55 to 65 decibels at normal distance, roughly equivalent to a quiet conversation. You should hear it from the backyard but not clearly from inside the house through closed windows. If it was always this loud and has not changed, it is normal.
Clicking at Startup and Shutdown
A few clicks when the system powers on or shuts off is normal electrical relay activity. You might hear two or three distinct clicks as the contactor engages or releases. This is expected behaviour and nothing to worry about.
Whooshing or Swooshing Sound Every Hour or So in Winter
This is the defrost cycle, and it is one of the most commonly misunderstood sounds a heat pump makes. When outdoor temperatures are near freezing, frost builds on the outdoor coil. The system periodically reverses refrigerant flow to clear it, which produces a whooshing sound followed by a brief release of steam from the outdoor unit. The fan may also shut off temporarily. This is completely normal.
Mild Gurgling or Refrigerant Flow Sounds
Refrigerant moving through the lines can produce a soft gurgling or bubbling sound, particularly at startup or when the system switches between heating and cooling modes. This is generally within normal range unless it becomes noticeably loud or is accompanied by a loss of heating or cooling performance.
Sounds That Mean Something Is Wrong
The following sounds indicate an issue that will not resolve on its own. Catching them early is the difference between a heat pump repair visit and a compressor replacement.
Loud Banging or Clanking
A bang or clank from the outdoor unit almost always means something is physically loose or broken inside the cabinet. The most common culprits are a loose fan blade, a broken motor mount, or a compressor with internal damage. Turn the system off and call for service. Running the unit with a loose component can cause secondary damage quickly.
Grinding or Screeching
This sound typically points to a bearing failure in the fan motor or the blower inside the air handler. Bearings wear over time, and when they start to go, friction creates a grinding or high-pitched screech. Left unaddressed, the motor will seize. A technician can replace the motor or bearing assembly before that happens, which is significantly cheaper than waiting.
Hissing or Bubbling Louder Than Usual
A pronounced hissing sound, especially one that did not exist before, often indicates a refrigerant leak. Refrigerant under pressure escapes through small cracks in line sets or fittings with a faint hiss. The system will also start to lose heating or cooling capacity as refrigerant levels drop. Understanding heat pump costs in Durham Region can help you weigh whether repair or replacement makes more sense once a technician diagnoses the leak.
Rapid Clicking That Continues Running
A few clicks at startup is normal. Rapid, repeated clicking that continues while the system is running usually means a relay or contactor is failing to hold properly. It can also indicate an electrical fault. This needs diagnosis before it strands you without heat on a cold Durham Region night.
Rattling from the Outdoor Unit
Rattling is often debris caught in the fan, a loose panel screw, or vibration from a unit that has shifted on its pad or stand. Before calling for service, it is worth visually inspecting the unit and clearing any obvious debris from around it with the system off. If the rattling persists after clearing the area, a technician can check for loose internal components.
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Why Proper Placement Reduces Noise Problems in Durham Homes
A significant number of heat pump noise complaints in Durham Region are not equipment problems at all. They are placement problems. When an outdoor unit is mounted directly on a deck, placed too close to a bedroom window, or installed without vibration isolation pads, normal operational noise gets amplified and transmitted into the home.
Proper installation involves mounting the unit on a raised stand or solid pad to prevent frost bridging and ground vibration, positioning the unit away from windows where occupants sleep, and ensuring adequate clearance on all sides for airflow. This is a core part of how HVAC Zack approaches every heat pump installation — placement and commissioning decisions made at install time determine how the system performs and how quietly it runs for years afterward.
If your heat pump was installed without those considerations, repositioning the unit is a straightforward job that can make a noticeable difference in how much noise reaches the interior of the house.
Seasonal Noise Changes Are Normal in Ontario's Climate
Durham Region winters push heat pumps harder than mild climates, and that means some seasonal variation in sound is expected. Cold-climate units running at high capacity in January will be louder than the same unit on a mild October evening. The compressor works harder, the fan moves more air, and the defrost cycle runs more frequently.
What should not change is the character of the sound. A unit that has always hummed but suddenly starts grinding, clicking rapidly, or banging has developed a new problem regardless of the season. Sudden changes in sound quality are the thing to pay attention to, not gradual increases in volume during a cold snap.
What to Expect from a Hybrid Heat Pump and Furnace System
Many Durham Region homes run a hybrid heat pump and furnace setup, pairing a heat pump with a gas furnace as the backup heat source. When the temperature drops below the heat pump’s balance point and the furnace kicks in, you will hear the furnace ignition and the gas burner start, which sounds noticeably different from the heat pump’s operation. That transition is not a problem. It is the system working as designed.
If you hear the system cycling back and forth between heat pump and furnace frequently on a moderately cold day, the system’s balance point settings may need adjustment. That is a configuration issue a technician can address in a single visit. If you are still running a standalone furnace and wondering whether a hybrid upgrade makes sense, the heat pump vs. furnace comparison for Durham Region is a good place to start.
When to Call HVAC Zack About Heat Pump Noise
A good rule of thumb: if the sound is new, if it has gotten noticeably worse over a short period, or if it is accompanied by a drop in heating or cooling performance, it warrants a service call. Heat pumps that develop problems and keep running tend to turn minor repairs into major ones.
If you are thinking about whether to repair or eventually replace, the heat pump cost guide for Ontario walks through what installed systems typically run and what factors drive the price up or down.
HVAC Zack services heat pumps of all makes and models across Oshawa, Whitby, Ajax, Pickering, Bowmanville, and Port Perry. If you are not sure whether what you are hearing is normal, the fastest way to get an answer is to call.
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About The Author
Zack Laundrie is a licensed and insured HVAC technician with over 15 years of hands-on experience serving Durham Region homeowners. He specializes in heat pump installation, hybrid systems, and honest diagnostics across Oshawa, Whitby, Ajax, Pickering, Bowmanville, and Port Perry.