How far should I open my damper?

Author: Athena Kessler  |  Last update: Thursday, February 26, 2026

Before you start a wood fire, always fully open the damper. Keep the damper fully open until all the embers are completely burned out. If you have a vented gas log set in your fireplace, turn off the flames before closing the damper as far as the safety C-clamp allows.

How far should a fireplace damper open?

You should turn the knob clockwise, as far as it can go, or push the rod all the way up to open the damper. If there is a metal chain in or besides your fireplace, it means that your chimney has a top-mounted damper. If the chain is tightly attached to a hook, the damper is closed.

Should the damper be fully open?

The fireplace damper should always be in the open position whenever you have a fire in the fireplace. Never close the damper or leave the fireplace unattended while there is a fire in the fireplace. This is not only a fire hazard, it can also cause deadly carbon monoxide poisoning.

Do you get more heat with damper open or closed?

As the air is closed down, more air is pulled through the secondary tubes. That starts burning waste wood gas for better and hotter combustion. So closing down the air actually makes the stove hotter. Running it wide open sends more heat up the flue liner.

What position should my damper be in?

HVAC Damper Open Or Closed In Summer/Winter

In most homes, dampers going to the upstairs are open in the summer and closed in the winter. By closing the dampers to the upstairs in the winter, it allows for the heat to rise naturally after first being introduced into the lower levels of the home.

How to Open a Fireplace Damper

What should my damper setting be?

What Damper Setting to Use. With a little experimentation, you will find the damper setting and drag factor that work best for you. We recommend starting out on a damper setting of 3–5. Really focus on technique, and as you improve, you may find that a lower damper setting gives you the best workout and results.

How do I make sure my damper is open?

Check for a draft

Stick your hand near the opening of the fireplace. If you feel air breeze against your hand, then it's safe to say that the damper is open. If there's a clear absence of a draft, then it's closed.

When should I close my HVAC damper?

In most houses, dampers on the upper level are opened in the summer and shut in the winter. In the winter, closing the dampers on your HVAC system to the upstairs allows for heat to rise naturally as it is distributed throughout the home.

How to maximize heat from a fireplace?

Evenly distributing small pieces of wood throughout the fireplace will increase air circulation and speed up the burning of the wood. This creates a sustainable fire, but the wood burns faster. Placing large logs closer to the fireplace will keep the fire burning longer between refills, maximizing heat output per log.

Is it OK to leave fireplace damper open?

OPEN OR CLOSED? The damper should be kept closed when there is no fire or coals burning. Warm air from your home will not be lost up the chimney when the fireplace is not being used. Fully open the damper before your start a fire and keep it fully open until all embers and coals have burned out.

How much to close a damper?

After you open the damper and light the fireplace, wait a few minutes for the fire to build into a productive fire. Then, partially close the damper about one-third of the way. This will retain more heat inside your home, leaving plenty of room for the fumes to vent.

Do you push or pull to open a damper?

Typically, to open the damper, push up or lift the rod all the way. Pull it down to close the damper. Another type of damper is a screw-type or rotary control damper. Typically, you will close the damper by turning it counterclockwise all the way, which causes the rod to hang down low.

How much heat is lost through an open chimney?

Warm air from your home naturally rises, and an open chimney provides an easy escape route. In fact, it's estimated that up to 30% of your home's heated air can be lost through an open chimney when the fire isn't in use.

Does closing the damper make the fire hotter?

Use the Damper to Control Heat

Depending on how far open or shut you have the damper, your fire will be smaller and cooler (and burn for longer), or larger and hotter (and burn more quickly). The damper is usually located at the bottom of the stove.

How to make a fireplace more efficient?

6 Tips to Make Your Fireplace Super-Efficient
  1. Burn Seasoned wood. Dry wood burns hotter and more efficiently than damp (unseasoned) wood. ...
  2. Chimney cleaning. ...
  3. Make sure your damper works correctly. ...
  4. Fix excess drafts inside your home. ...
  5. Convert an inefficient masonry fireplace.

How to set the damper on a fireplace?

The damper has notches, so you can partially close it (throttling), like a manual stick shift in a car. Next, when an intense fire burns in the fireplace, you can manually set the damper in the first notch position, slightly closing it.

How do I get the most heat out of my open fireplace?

Get the Most Out of Your Fireplace This Winter
  1. Burn seasoned firewood. Fresh wood has a high moisture content. ...
  2. Close the dampers. ...
  3. Reverse the circulation of ceiling fans to spread the warmth. ...
  4. Use glass fireplace doors to reduce heat loss. ...
  5. Install a fireplace insert to increase heating efficiency.

Why can't I feel the heat from my fireplace?

Issues may arise from a variety of factors: creosote build up or other blockages in the chimney flue, insufficient ventilation, or negative air pressure within the home. These factors impact not only the heat of your fires, but also the safe usage of your fireplace system.

How do I make my fireplace fire burn longer?

To make your fire burn for longer, reduce the airflow by partially closing the damper or adjusting the air vents. This helps regulate the oxygen supply to the fire, creating a slower and more controlled burn that can last for extended periods.

Does closing a damper increase heat?

By not creating an airtight seal, these dampers minimize the strain on the system. In summer, you can close the dampers downstairs so cooler air reaches upstairs rooms. But in winter, closing upstairs vents halfway allows heat to rise.

How to check damper position?

Inspect the Handle Position

If your dampers use a manual handle, check the handle's position to determine whether the dampers are open or closed. The HVAC damper is open if the handle is parallel to the ductwork. If the handle is perpendicular to the ductwork, the dampers are closed.

Should damper be fully closed?

The damper to your fireplace must be completely open when a fire is burning. If you close the damper even slightly, you risk allowing smoke and other dangerous contaminants from the combustion process into the house. And remember, the most dangerous by-product of combustion is carbon monoxide.

Should I open my damper all the way?

Proper Damper Use

It's important to open the damper all the way when you're using your fireplace, a partially open damper can allow smoke and gases to escape, but can also cause a backdraft that can bring cold air into the home. When you're not using your fireplace, it's important to close the chimney damper.

How often should I clean my chimney?

Regularly cleaning your chimney (about once a year) will reduce the amount of creosote in your chimney and should greatly reduce the risk of any chimney fires in the future. It's also important to make sure that the chimney cap is in good condition and that there are no gaps or holes in the flue.

How to set dampers in summer?

You want to start by making slight adjustments in each room. If a room is too hot, you will want to crank open the damper just a bit to add more airflow to the room. If a room is too cool during the summer, you will want to slightly close the vent so that it stops some of the air from entering that room.

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