Furnace runs but some rooms are too hot while others are too cold.

Safety: Most balancing adjustments are safe for homeowners, but do not close too many registers, which can overheat the furnace.

Steps:

• Open all registers: Start with all supply registers fully open.
• Partially close over-conditioned rooms: Slightly close registers in rooms that get too warm to push more air to cooler rooms.
• Inspect ducts: Look for disconnected or crushed ducts, especially to rooms that are too cold.
• Check filter: Ensure a clean filter is installed to maintain proper airflow.

When to call a technician: Persistent imbalance may require duct modifications, zoning, or blower speed adjustments by an HVAC professional.