Five signs your ductwork is costing you money

Homeowners replace equipment when comfort fails. Contractors love selling equipment. But in a huge share of the homes we test, the equipment was never the problem — the ducts were.

1. Rooms that never match

If the thermostat says 72° but the back bedroom lives at 78°, air isn't arriving where it should. Long duct runs with unsealed joints shed conditioned air into the attic all along the way, and starved returns leave rooms pressurized against the very air they need.

2. The dust that comes back overnight

Return-side duct leaks vacuum air from attics and wall cavities — insulation fibers, soil gas, the works — and inject it into your airstream downstream of the filter. If dusting feels futile, your ducts may be importing the dust.

3. Summer bills that outpace the neighbors

At 20–30% leakage — the measured average for homes that have never been sealed — you're paying to condition your attic. On a $350 August bill, that's real money going through literal holes.

4. A system that runs long but never satisfies

When supply air leaks away before reaching registers, the thermostat waits longer for the same result. Long runtimes with mediocre comfort usually point at distribution, not capacity — and a bigger unit would just leak more, faster.

5. Whistling, rattling, or booming ducts

Airflow noise is a pressure signature. Whistles mean high-velocity leaks; booms on startup mean flexing, undersized trunks. Healthy duct systems are quiet.

What testing looks like

A proper duct test takes about an hour: we pressurize the system with a calibrated fan and measure exactly what leaks, in CFM. You get a number, not an opinion. Sealing typically runs $1,800–$3,600 and returns 15–25% of cooling costs annually — the strongest ROI in residential HVAC, and nobody advertises it because it doesn't come with a shiny box.