AC Not Cooling Upstairs
It is one of the most common comfort complaints in DMV two-story homes: the upstairs stays hot no matter how low you set the thermostat. Heat rises, ductwork is often undersized for the second floor, and small airflow problems get magnified. Here is what is really going on.
Common Causes
Undersized or Leaky Ductwork
Second-floor runs are often long, narrow, or leaky, so not enough cold air reaches the upstairs rooms.
Low Refrigerant or Dirty Coil
A system low on refrigerant or with a dirty evaporator coil loses capacity, and the upstairs feels it first.
Poor Insulation / Attic Heat
A hot attic radiates into upstairs ceilings. Without enough insulation and sealing, the AC simply cannot keep up.
Warning Signs
- !A 5-10°F difference between floors
- !Weak airflow from upstairs vents
- !The system runs constantly but never catches up
- !Higher energy bills than last summer
How We Fix It
- 1Measure airflow and temperature split to find where capacity is being lost.
- 2Seal and balance ductwork, replace filters, and clean the coil; check refrigerant charge.
- 3Recommend targeted fixes, damper adjustment, return air, insulation, or a zoning solution.
What It Costs
Diagnostics and common fixes (coil cleaning, charge, duct sealing, balancing) typically run $150-$900. Larger duct or zoning work is quoted after inspection.
If You Ignore It
A system that runs flat-out all summer wears out years early, your bills climb, and the upstairs stays miserable. Catching airflow and charge issues early protects the equipment.
Frequently Asked Questions
Do I need a whole new system?+
Will closing downstairs vents help?+
How fast can you get to me?+
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