Heat Pump Noise: Handling the Winter Hum from Your Neighbor's Unit

Why They Get Louder in Winter

In cold weather, a heat pump's compressor runs at a higher speed to extract heat from the outside air. Additionally, the unit must periodically enter a "defrost cycle" to melt ice off the coils. This cycle can cause:

• Whooshing sounds: From the reversing valve shifting.
• Steam/Hissing: As ice melts.
• Increased Vibration: Ice buildup on the fan blades can cause the unit to wobble and vibrate, sending low-frequency noise through the ground.

Tonal Noise and Ordinances

Standard decibel readings (dBA) often fail to capture the annoyance of heat pumps because they filter out low-frequency bass sounds. However, some advanced noise ordinances have penalties for "tonal noise"—a sound that is concentrated at a single frequency (like a hum or whine).

Even if the unit is technically under the 55 dB limit, a distinct, penetrating hum can still be classified as a nuisance under "unreasonable noise" clauses if it is audible inside your bedroom.

Solutions to Suggest

This is a mechanical issue, not a behavioral one. When talking to your neighbor, approach it as a repair problem:

• Vibration Isolation Pads: Suggest installing rubber pads under the unit's feet. This is a cheap fix that stops the hum from traveling through the ground or deck.
• Snow Clearance: Politely mention if the unit looks buried in snow, as this restricts airflow and increases noise.
• Sound Blankets: Compressor sound blankets can be installed inside the unit to dampen the motor noise.

The Takeaway

If a neighbor's heat pump is disturbing your sleep, it's likely working too hard or needs maintenance. Framing the conversation around efficiency and maintenance ("I think your unit might be struggling, it's making a loud vibrating noise") is often more effective than a standard noise complaint.