What to know
Damage and accumulation feel different
Build-up happens slowly and fairly evenly. Everything drifts a little over several seasons and nobody can name the month it started.
Damage tends to be sudden or specific. One room changed. A noise appeared. Airflow dropped and stayed down. Something happened, even if nobody noticed it happening.
The most common ways ducts get damaged
- Somebody walked on a run in the attic, or stored boxes on it.
- Remodelling work disconnected a run or a boot and nobody reconnected it properly.
- A flex run has sagged over years until it kinked at a low point.
- Rodents, which is more common in crawl spaces than most homeowners want to think about.
- Corrosion in older metal ducting, particularly where moisture has been present.
- A previous repair done with the wrong tape, which held for a while and then let go.
What you can check
- Compare airflow room to room, and note whether the weak ones are grouped or scattered.
- Listen when the system starts. A new rattle, whistle or rushing sound is worth locating.
- Look at any accessible run for sections that sag, kink, or hang disconnected.
- Check whether the problem began around the time work was done anywhere in the house.
- Pull a register cover and look for daylight, gaps, or a boot that has separated from the floor or wall.
Why it matters which one you have
They lead to completely different work. Cleaning a system that has a disconnected run leaves you with a clean system and the same cold bedroom, and a bill you did not need to pay.
It is also why a quote given before anyone has looked at your ductwork is worth very little. The two problems are not distinguishable from the thermostat.
What we would do
Look at the accessible ductwork and tell you which of the two you have, with photographs. If it is accumulation, we will explain what cleaning involves and what it will and will not change.
If it is damage, that is a different job and sometimes a different trade, and you should hear that from us before anything is scheduled.