Furnace runs but some rooms are much colder than others

Safety first: Ensure registers and grilles are not obstructed by flammable materials.

• Step 1 – Open all registers: Make sure supply registers in cold rooms are fully open and not blocked by furniture or rugs.
• Step 2 – Inspect accessible ducts: Look for disconnected or crushed ducts in attic, basement, or crawlspace. Reconnect and support as needed.
• Step 3 – Basic balancing: Slightly close registers in overheated rooms to push more air to colder rooms.
• Step 4 – Professional duct evaluation: For persistent issues, have a technician perform a duct balancing and airflow test.