Record the pattern without touching the unit

From a safe distance, note when the noise begins, its duration, outdoor conditions, and whether the sound ends when normal heating resumes. Record a short video if you can do so without approaching moving parts.

Distinguish a brief change in operating sound from rattling, scraping, banging, or vibration felt through a wall. Note whether the sound has changed since installation and whether ice clears afterward. Do not remove covers, chip ice, or disable defrost to reduce the noise.

If the unit is heavily iced, heating declines, or the noise is newly severe, report that when arranging service.

Ask for two separate findings

First, have the technician confirm whether the sound and defrost sequence fit the exact model. Ask them to check the installation and any suspected vibration or fault, rather than simply say “heat pumps do that.”

Second, ask whether the outdoor location, mounting, and sound reaching the bedroom or property line need improvement. Equipment functioning correctly does not automatically mean the placement is appropriate.

Ask the installer to identify applicable local sound requirements and how any sound assessment should be performed. A phone recording is useful evidence of the complaint, but it is not a reliable compliance measurement.

Compare remedies that preserve operation

If vibration or a fault is found, request the correction and a follow-up check during the relevant operating mode. If the issue is placement, compare approved mounting changes, relocation, or a manufacturer-approved sound measure with the appropriate installer.

Do not build a tight enclosure, block airflow, or modify the fan to quiet the unit. Any proposed screen or barrier needs suitable clearances and service access.

Your next step is to share the recording and timing notes with the installer and request both the model-behavior check and placement review. The useful outcome is an explanation of what is normal, what can be corrected, and how the proposed change addresses the sound where it affects daily life.