Vent, Valve & Volt
Weak airflow from vents, or one room hotter or colder than the rest

You can fix this

Likely cause: closed or blocked registers

A register that's closed or covered by furniture, a rug or a curtain can't deliver air to the room. Open and clear it.

Why this happens

The LibreTexts HVAC course lists blocked vents among the causes of both weak airflow and uneven temperatures, and Hoffmann Brothers lists obstructed grilles. Even a partly covered register cuts what reaches the room.

How to fix it

  1. Open the register louvers fully.
  2. Move furniture, rugs and curtains so nothing covers the register or sits right in front of it.
  3. Check the room's return grille, if it has one, and clear it the same way.
  4. Give the system a full cycle and feel the airflow again.

When to stop. If the register is open and clear and the airflow is still weak, the problem is in the duct to that room.

If this does not fix it, tell the HVAC technician

  • Which registers were closed or blocked.
  • Whether the room improved after you cleared them.

Build the full list: what to tell the HVAC technician.

Start this troubleshooter over

References (every fact above comes from one of these pages)
  1. LibreTexts (Coalinga College HVAC course): Common air distribution problems and solutions
  2. Hoffmann Brothers: What triggers low airflow from AC vents

Vent, Valve & Volt is published by the team behind FourHome. Browse all FourHome replacement faucet and shower parts on the FourHome Amazon store.