You have just bought an older home in Silver Spring. The inspection flagged a few things, the heating and cooling system works, and nobody mentioned the ductwork.
Home inspections cover whether the system runs. They rarely cover what is inside the ducts, how the runs are laid out, or what the previous owners did or did not maintain. Here is what is worth checking yourself in the first few months.
Why Older Local Housing Is Worth a Closer Look
Much of the detached housing around Silver Spring and the neighbouring Montgomery County communities dates from the middle of the last century. A house that age has usually been through several owners, at least one heating and cooling system replacement, and often an addition or a basement finish.
Each of those changes touched the ductwork. New equipment gets fitted to old duct runs. Additions get new branches spliced into the existing system. Basements get finished and runs extended into spaces that were never conditioned before.
The result is that two houses on the same street, built the same year, can have completely different duct layouts. You are inheriting whatever decisions were made along the way, and no record of them.
Check the Filter First
Pull the filter out on day one. It tells you something about the previous owner’s maintenance habits.
A filter that is grey and matted suggests it has been in place a long time. A filter that is the wrong size for the housing, or wedged in at an angle, means air has been bypassing it entirely.
Replace it regardless, following the manufacturer’s instructions for the unit, and note the size while you are there.
Look Inside a Few Registers
Take the cover off a floor register and shine a phone light down the duct. Do two or three in different parts of the house, including at least one return.
Plain sheet metal with a light film of dust is normal and nothing to act on. What is worth noting:
- A matted grey layer coating the duct walls
- Clumps of pet hair, if the previous owners had animals
- Fine white powder, which usually means drywall work and often a renovation that was never cleaned up after
- Construction debris, offcuts or rubbish left in the run
- Yellowing or staining, which can indicate smoking in the house
- Any sign of pests
Walk the Basement and Crawlspace
Follow the duct runs where you can see them. You are looking for sections that have come loose, insulation that has sagged or fallen away, flex duct that has been crushed or kinked, and tape or mastic that has let go at the joints.
A disconnected return in a basement is more common than people expect, and it means the system has been drawing unconditioned basement air into the house rather than returning room air.
Check Airflow Room by Room
With the system running, hold your hand near each supply register. You are not measuring anything precisely, just noticing whether one room is getting noticeably less than the others.
Weak airflow in one room has several possible causes: a closed or stuck damper, a crushed flex run, an undersized branch, buildup restricting the duct, or a run that was never properly connected after a renovation. Worth identifying which, rather than assuming.
Notice What the System Smells Like
Run the heating and the air conditioning, separately, and pay attention when each starts.
A musty smell when the blower starts is worth tracing. It can come from moisture in the system, a dirty condensate pan, or buildup in the ductwork. Previous occupants’ cooking smells and smoke can also settle into duct buildup and release slowly, which is one of the more common complaints from new owners of older homes.
Should You Have the Ducts Cleaned?
Not automatically. The EPA does not recommend duct cleaning simply because time has passed, and a system in reasonable condition may not need it.
Moving in is a reasonable trigger for an inspection, though, for one specific reason: you have no history. You do not know whether there was a renovation, whether anyone smoked, whether pets lived there, or whether the ducts have ever been cleaned. An inspection replaces guessing with knowing.
If what you find is a light film of dust on plain metal, you can leave it. If you find a matted layer, drywall powder, or debris left behind by a contractor, that is a different answer.
Getting It Checked
We provide air duct cleaning in Silver Spring and the surrounding Maryland communities, and we see a lot of systems in homes that have just changed hands.
We inspect first and tell you what is actually there. If the ductwork does not need cleaning, you will hear that.
Call 888-509-3828 or request an estimate.