What Does Direct Vent Mean?

Posted in: Indoor Fireplaces
Homeowners throughout the U.S. are switching to a direct-vent gas fireplace or stove to heat their homes efficiently and safely. Some people, though, are unsure of what direct-vent is or how it works. In our guide, we explain what a direct-vent fireplace is with the definition, types of fireplaces, and how to add a direct-vent appliance to your home.

What are Direct-Vent Gas Fireplaces?

Direct-vent technology describes a gas-burning appliance that uses two pipes - often one smaller pipe within another larger pipe - to both exhaust the flue gases and bring in fresh air for combustion. They are one of the safest, most convenient, and most popular ways of adding a gas fireplace to your home. The area where the fire takes place, often called the combustion chamber or firebox, is sealed with a glass panel and gaskets protected by a safety barrier screen. This allows you to enjoy the view of the fire while preventing fumes from coming into the home or already-heated room air from escaping out the chimney.

How Do I Add a New Fireplace to My Home?

A direct vent built-in fireplace can be built into a wood-framed structure with proper clearances. Built-in fireplaces can be vented either vertically or horizontally with the proper direct-vent piping and vent caps. This allows for flexibility when selecting the location of the fireplace. Always review the installation instructions with regards to the length and direction of venting as it differs with every appliance. See the example here.

Direct Vent Diagram

How to Convert a Fireplace to Direct-Vent

If you have an existing wood-burning fireplace you can convert it with a direct-vent gas insert. The venting for an insert typically consists of two separate three- or four-inch diameter flexible aluminum pipes. One exhausts the flue gases and the other one draws in fresh air used for combustion. This is unique to direct-vent inserts because they are either installed into an existing masonry structure or a metal zero clearance wood fireplace with an insulated chimney system. There are also direct-vent freestanding stoves that you can add without building a new fireplace from scratch. As always, please consult the manual and local codes for proper and safe installation.

Direct Vent Inserts

Whether you are installing a built-in direct-vent fireplace, a direct-vent insert or a direct-vent freestanding stove, the principles are all the same. You get clean-burning, efficient heat from a gas burning appliance that looks like its burning real wood! Again, make sure to consult the appliance manual and local code to assure the installation is done properly.

Direct Vent Free Standing

(All images are courtesy of the National Fireplace Institute)

Direct-Vent Gas Fireplace Frequently Asked Questions

Do direct-vent fireplaces need a chimney?

While you can exhaust a direct-vent fireplace out a chimney and flue, it is not required. They also can be vented vertically through the roof or horizontally via a sidewall. This eliminates backdraft so harmful gases don't get sucked right back into the home.

How far can you vent a direct-vent fireplace?

There is no maximum distance for venting a fireplace - though you will need vertical lengths if the vent is longer than 20 inches. However, the amount of clearance you need for direct-vented appliances can vary. Among other things, the vent terminal should be at least 36 inches above forced-air intakes, 24 inches from outside building corners and 12 inches above any openable door or window.

Can a pellet stove be direct-vented?

A direct-vent pellet stove gives you the benefits of gas stoves with maximum efficiency. Some wood pellet stoves can be vented horizontally through the wall much like gas fireplaces. However, certain manufacturers discourage this due to safety concerns, so check the product information before proceeding.
July 27, 2023
1437 view(s)