Why does my fireplace have 2 vents?

Author: Mrs. Karolann Jacobi  |  Last update: Thursday, June 12, 2025

Specialized venting includes a “direct vent” that has two chambers that work together to perform dual purposes: one chamber draws oxygen in from the outdoors for the fire, while another expels the fire's byproducts and gases outside.

Why does my fireplace have two vents?

Old fireplace with a second vent, what is it for?
  • an air vent, to allow fresh air right into the heart of the fire.
  • leftover from an old gas/wood stove, where it needed a vent there for the back of it.
  • Another vent for the smoke.

What are the two vents above my fireplace?

The two vents on the side are air intakes. There should be fans behind those vents. The vent at the top is where the air comes out. There are air ducts behind and above your firebox.

Why are there vents on the side of my fireplace?

They are used to cool the fireplace when it is in use so the framing of the home surrounding the fireplace doesn't dry out to the point that it can combust.

Why does my fireplace have 2 flues?

In older houses located in colder climates, it was fairly common to have one chimney with two or more separate flues. This would allow a homeowner to vent, say, an oil-burning appliance as well as one, two, or even three wood-burning stoves/fireplaces. “Older” is the keyword here: these houses were not airtight.

Don't CLOSE Your Vents!

What is the difference between single flue and double flue?

Single wall flue pipe is not insulated and therefore loses a lot of heat. The layer of insulation in twin wall flue keeps the flue gases warmer, allowing the flue to perform correctly and efficiently, whilst also reducing the build up of condensates within the flue system.

Why does my log burner have 2 vents?

Most wood burning stoves and multi-fuel stoves have a bottom air vent and a top air vent. Wood burns best with a good bed of ash laid down in the bottom of the stove and an air supply from the top. When lighting your stove, open both air vents fully.

What are the side vents on a fireplace for wood?

Side Vent. A side vent fireplace, aka co-axial direct vent, is vented horizontally through a wall to the outside. Zero-clearance direct vent fireplaces are used in homes without existing fireplaces and chimneys.

Should your fireplace vent be open or closed?

Dampers are in place to control the flow of air between your home and your chimney flue and everything beyond it. In other words, inside air, and outside air. When the fireplace is in use, the damper (whether it's a throat damper just above the firebox or a top-mount damper at the top of the chimney) must be open.

How do I control the airflow in my fireplace?

A damper is a device that regulates airflow in the flue. When open, oxygen enters the chimney to fuel the fire as the poisonous gases vent out of the home. Shutting the damper prevents outside air from mixing with the indoor air, increasing energy efficiency.

How do vents on a fireplace work?

“A direct vent appliance draws its combustion air from outside and the vent exhausts the combustion fumes to the outside as well—it does that all through the direct vent pipe.”

How do I know if my fireplace vent is closed?

If you don't feel any cold air coming down the chimney, it means that the damper is closed. Another way to find out if the damper is open is to do a visual check. If your chimney has a traditional damper, all you need to do is shine a flashlight up the chimney. If you can see the sky, it is open.

Why is my fireplace not venting properly?

There are a few ways problems with your fireplace and chimney can affect venting: Blockages in the chimney – when something is physically blocking your chimney, the drafting process is completely interrupted. Common blockages are insect and animal nests, an incorrectly-sized flue cap and faulty dampers.

How do I get more air in my fireplace?

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.

Why is there two air vents in my room?

Having multiple return air vents in the home allows for better air movement and helps to reduce the pressure on the HVAC system.

Does each fireplace have its own flue?

Each fireplace will have it's own separate flue which is divided by the mid feathers. The chimney breast in a lounge will usually house two flues; the lounge fireplace itself and also the bedroom fireplace directly above.

Is it OK to leave fireplace flue open?

It's best to keep the flue closed when the fireplace is not in use.

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.

Why is there a vent on the side of my fireplace?

It makes perfect sense that direct vent gas fireplaces are the most purchased hearth systems today. They offer convenience and safety, with sealed combustion systems that protect indoor air quality by drawing outside air for the fire and expelling 100% of combustion exhaust and byproducts outside the home.

Should the vent on my fireplace be open or 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.

What is the secondary vent on a wood burner?

The secondary air vents are strategically placed in the upper part or sides of the stove to introduce fresh, pre-heated air into the combustion chamber above the fuel bed. This additional oxygen helps burn off any unburned gases, reducing emissions and promoting a cleaner, more efficient burn.

What is the primary and secondary air on a wood burning stove?

The primary air is therefore closed down once the stove is fully lit and the airflow controlled with the secondary air control. As above in "Air", confusingly the "secondary" air is the one you will primarily control the stove with when burning wood! Coal burns best with a supply of air from below.

Why does my furnace have 2 vents?

Most central air heating and cooling systems have 2 intake vents that help circulate your home's air and clean out any debris by running it through an air filter.

Why does wood burn better on a bed of ash?

The remaining ashes help the wood burn faster. The ashes have properties that allow them to enclose the fire's warmth and reflect it into the wood, resulting in a faster burning process.

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