How to Open a Fireplace Flue
Using Your Fireplace Damper
Understanding how to properly open and close your fireplace flue is essential for safe, efficient fireplace use. Whether you own a traditional wood-burning fireplace or a modern unit with a built-in damper system, knowing how the flue works helps ensure smoke vents correctly and your home stays comfortable. Here’s a simple guide to what a flue is, why it matters, and how to adjust it safely.
Need professional fireplace service from friendly, dependable professionals? Schedule with Fireside Home Solutions today and our team will be happy to help.
What Is a Fireplace Flue?
The flue is the vertical passage inside your chimney that allows smoke, gases, and exhaust to move safely out of your home. Think of it as the chimney’s airway. Inside that flue, there is a movable component called the damper. When people talk about “opening the flue,” they are actually opening the damper—the metal plate that opens or closes to let air flow through the flue.
If the damper is closed while a fire is burning, smoke has nowhere to go and will quickly fill the room. If it’s left open after the fire is out, you can lose heated indoor air through the chimney. That’s why understanding the difference—and how to operate the damper—is so important.
When and Why You Should Open or Close the Flue
Your flue (via the damper) should be adjusted based on whether your fireplace is in use:
- Open the flue before starting a fire. This allows proper ventilation so smoke, fumes, and combustion gases escape up the chimney instead of entering your home.
- Leave it fully open while the fire is burning. Even smoldering embers produce smoke and gases.
- Close the flue once the fire is completely out and the fireplace is cool. This helps prevent warm indoor air from escaping and stops outside drafts from coming in.
If you’re ever unsure whether a fire is fully extinguished, give it extra time before closing the damper.
How to Open a Fireplace Flue (via the Damper)
Because fireplace designs can vary, your specific damper style may look a little different—but most fall into one of two categories: throat dampers (located just above the firebox) or top-mount dampers (located at the top of the chimney). Always make sure the fireplace is cold before reaching into or adjusting any components.
1. Locate the Damper Control
For throat dampers, you’ll usually find:
- A lever you push or pull
- A rotary knob you twist
- A sliding handle inside the firebox
For top-mount dampers, the control is typically a metal chain that hangs down into the fireplace.
2. Check Whether the Damper Is Open or Closed
Before lighting a fire, visually verify the damper’s position:
- Look up into the chimney with a flashlight.
- An open damper will reveal an unobstructed vertical passage.
- A closed damper will appear as a solid metal plate blocking the flue.
3. Open the Damper
Adjust your damper control according to your model:
- Lever or handle: Push or pull until the plate swings fully open.
- Rotary knob: Turn until you feel the damper move into the open position.
- Top-mount damper chain: Release the chain from its notch so the spring mechanism opens the damper at the top of the chimney.
Make sure the damper is wide open before starting your fire to ensure proper airflow.
4. Close the Damper After the Fire Is Out
Once the fireplace is completely cooled, return the damper to the closed position to improve energy efficiency and prevent drafts. Never close it while ashes are still hot or smoldering.
Tips for Safe and Easy Damper Use
- Inspect the damper annually for rust, warping, or debris buildup.
- Keep the fireplace clean to help the damper operate smoothly.
- Always open the damper before lighting kindling—smoke forms quickly.
- If the damper sticks or won’t fully open, schedule a professional inspection.
A well-functioning flue and damper system keeps your home safe and your fireplace performing at its best.
Why Choose Fireside Home Solutions?
From helping you understand your fireplace components to providing expert maintenance and repairs, Fireside Home Solutions is here to ensure your system runs safely and efficiently. Serving the Seattle and Portland areas, our team specializes in fireplaces, garage doors, and year-round home comfort solutions.
If you have questions about your fireplace or need help servicing your damper or chimney system, contact us today. Call us to learn more about our fireplace and garage door services or to schedule your next tune-up.