Furnace runs but some rooms are much colder than others.

Safety first: Turn off power before opening any duct panels.

Homeowner checks:

• 1. Open all registers: Ensure supply registers in cold rooms are fully open.
• 2. Check for obvious duct leaks: In accessible areas, look for disconnected or crushed ducts. Seal small gaps with foil tape (not cloth duct tape).
• 3. Ensure return air path: Keep doors open or undercut to allow air to return to the furnace.

When to call a professional: A technician can measure airflow, adjust blower speed on the Philco control board, and recommend duct modifications.