Should the damper be fully closed?

Author: Julien Aufderhar  |  Last update: Tuesday, May 26, 2026

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 the fireplace damper close all the way?

No you would never burn with the top mount damper closed. The damper should be fully open when burning. The top Mount damper is more to keep warm air in and cold air out when your not using the fireplace. You should be able to adjust the handle on the cable coming down the chimney so it closes all the way.

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.

Should the damper lever be open or closed?

It connects to a lever that rotates to redirect airflow throughout your ductwork. For example, opening a damper allows the temperature-controlled air from your furnace or air conditioner to flow through that area of your duct system, while closing it restricts that airflow.

Is it okay to leave the damper open?

One common myth about chimneys is that leaving the damper open during the summer helps “air out” the chimney. However, the opposite of true. Leaving the damper open just fouls up the rest of your home, and does nothing to clean your chimney.

Chimneys Explained #16 - Chimney Dampers

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.

How far should I open my damper?

always fully open the damper. If you're burning wood, keep it fully open until all the burning embers are completely burned out. If it's a gas log set, turn off the flames before the closing the damper as far as possible.

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.

What happens if you don't open the damper?

You need to open the damper when you start a fire to allow for proper airflow and let the smoke out. A closed damper can restrict airflow and become a safety issue since smoke would fill your house.

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.

Can you partially close a damper?

Damper Throttling

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.

Can you go to bed with embers in the fireplace?

No, you should never leave a fireplace burning overnight or unattended during the day.

How do you know if your damper is closed?

#2 Check for a draft.

Maybe you can't see the damper or aren't sure whether it's a little open or closed all the way. A second way to know is to stick your hand near the opening of the fireplace. If you feel a breeze of air, the damper is open. If you don't feel a draft, it's closed.

Do you get more heat with a damper open or closed?

The handle to open and close the damper should be above the fireplace opening. To open it, slide it to the right. To create fires that produce more heat, open the damper as wide as possible when lighting a fire. A wide-open damper will increase the amount of air reaching the fire and improve combustion.

What is the difference between a flue and a damper?

The damper and flue are two different parts, but they are related and involved in the same function. The flue is the inside tunnel of your chimney that brings gases from your fireplace out of your home, while the damper closes or opens the access to the flue.

How to tell if gas logs are ventless?

Ventless logs tend to have smaller, blue-tinted flames due to their high-efficiency design. Vented logs, on the other hand, often produce larger, yellow flames for a more natural appearance. Ventless gas logs always include an Oxygen Depletion Sensor (ODS).

Should the fireplace damper be closed in summer?

One common question we get is whether you should close your fireplace during the summer or not? The answer is yes in most cases – we recommend closing your damper when your fireplace is not in use. The only instance where you should keep your fireplace open is if you have a set of gas logs.

Should dampers be closed in winter?

When Should I Open and Close My HVAC Dampers? 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.

What is the lever on the side of my fireplace?

The handle on the left-hand side is for your combustion air intake; think of this as a gas pedal in a car but is used for controlling the intensity of your fire. The handle on the right-hand side is for your flue damper; this control is used primarily to slow down the chimney draft.

Should damper be fully open?

A closed damper also stops cold drafts from coming down the chimney. When you are using your fireplace, it needs to be open so that smoke can vent outside. It also allows fresh air to come in to feed the fire.

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.

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 to get more heat from a fireplace?

Increasing Fireplace Efficiency
  1. Install a Glass Fireplace Door. Installing a fireplace door is an effective and inexpensive solution to get more heat out of your fireplace. ...
  2. Use a Fireback. A fireback is an accessory that attaches to the back of the fireplace. ...
  3. Upgrade Your Fireplace. ...
  4. Use the Damper to Turn Up the Heat.

Are dampers normally open or closed?

Outside and exhaust dampers will generally revert to a normally-closed (NC) position, while return air dampers will revert to their normally-open (NO) position to ensure that any supply fans are not deprived of fresh air.

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.

Previous article
Why do I hear walking in my walls?
Next article
What is a silent wash?