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AC Not Blowing Air
in Portland, ME
The outdoor unit hums along and the thermostat says it's running, but the vents are quiet. The blower motor in the indoor air handler is supposed to push air through the duct system and out the vents. When it fails or when the ducts get blocked, air stops moving. Portland homes with duct systems in unconditioned attics or crawl spaces see this more often because the ducts are exposed to temperature extremes and sometimes get crushed or disconnected.
Quick Answer
When your AC runs but no air comes from the vents, the blower motor or a collapsed duct is usually the problem. In Portland homes built before 1980, older flex duct can sag and close off over time. A failed blower motor means no air moves at all even if the compressor is running fine. Call (207) 544-5500 so a tech can check which part of the system stopped moving air.
Telltale Signs
Warning Signs to Watch For
- No air movement from the vents even though the system is running
- Very weak airflow from some vents but not others
- The air handler runs but you can't feel or hear airflow at the registers
- One section of the house has no airflow while other rooms are fine
- The system runs longer than normal without reaching the set temperature
Root Causes
What Causes AC Not Blowing Air?
Failed Blower Motor
The blower motor is the fan inside the air handler that pushes air through all the ducts. When the motor fails, air simply stops moving even if the compressor outside is still running. Motors in systems that are more than 12 years old can fail without warning, and Portland's humid summers put extra load on them.
The Fix
Blower Motor Replacement
A tech removes the failed motor and installs a replacement. The motor size and speed settings need to match the original so airflow is correct throughout the duct system.
Collapsed or Disconnected Duct
Flex duct is a flexible insulated tube used to carry air from the air handler to each vent. In attics and crawl spaces common in Portland homes built in the 1960s and 1970s, flex duct can collapse under stored items, sag closed over time, or pull apart at connections. A disconnected duct dumps conditioned air into the attic instead of the room.
The Fix
Duct Inspection and Repair
A tech inspects the duct run to the affected vents, reconnects any separated sections, and supports or replaces collapsed flex duct. Sealing the connections properly stops air from leaking into unconditioned spaces.
Self-Diagnosis
Which Cause Applies to You?
Check the signs you're observing to narrow down the likely root cause before your inspection.
| What You're Seeing | Failed Blower Motor | Collapsed or Disconnected Duct |
|---|---|---|
| No airflow from any vent in the house | ||
| No airflow in one room only, other rooms fine | ||
| Air handler runs and hums but no air moves | ||
| Weak airflow in one zone, strong in another | ||
| System runs but house temperature barely changes |
Free Inspection
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An on-site inspection is the only way to confirm which cause applies to your property. Free, no obligation.
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