Sound Calculations and Condenser Placement in Seattle Heat Pumps
Seattle city inspectors reject nearly 35% of HVAC applications due to poor noise level projections. Here is how PermitCrab can help draft compliance narratives in seconds.
By PermitCrab Editorial
Seattle Municipal Code 25.08 sets residential nighttime noise limits at 45 dBA at the receiving property line. Most modern heat pump condensers are rated 55–68 dBA at 3 feet, so placement and barriers become the deciding factor for permit approval.
Include a scaled site plan showing the condenser location, distance to the nearest property line, and any acoustic barriers. Manufacturer sound data sheets should be attached — not just referenced.
PermitCrab's narrative generator will automatically pull the correct SMC section, calculate expected dBA at the property line based on distance attenuation, and flag units that need supplemental sound mitigation before you submit.
Pro tip: If you're within 10 feet of a shared property line, expect a second review round unless you preemptively include a signed statement from the homeowner acknowledging the placement.