Uses room air for combustion and venting terminates above the roofline (like a furnace).
More decorative, lower efficiencies.
Zero clearance to combustibles.
Relatively easy to install, space-saving depth, but requires finishing such as a mantel and surround.
Large traditional fireplaces in clean-face or circulating models.
Ideal for locating anywhere in the home where B-vent can be installed.
Less Cost than Direct Vent.
The Hearth, Patio & Barbecue Association recommends the installation of a carbon monoxide detector with all gas hearth products.

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Vent-Free

A vent-free gas fireplace operates without a chimney, flue or vent, so you can install one just about anywhere. Choose from vent-free gas fireplaces, stoves, fireplace inserts and gas logs. Modern vent-free gas fireplaces:

are inexpensive and have low operating costs
are 99 percent energy efficient and provide warmth during power outages
are Design-Certified to the latest national safety standards (ANSI Z21.11.2)
do not exceed 40,000 Btu/hr of heat output
and are a source of pleasure for years to come.

Eight million American homes and more than 45 million households worldwide already enjoy the comfort and convenience of vent-free gas fireplaces. In fact, more Americans are buying vent-free gas fireplaces than any other type of supplemental gas heating product. However, there are some areas where these units are restricted. Consumers must check with their local building departments before purchasing

How they work

Vent-free fireplaces operate on natural or propane gas. Most models require no electricity. Natural or propane gas fuels the flame through a permanent line that is connected to a blue-flame/yellow-flame burner or ceramic plaque burner within the heating appliance.
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Indoor air quality

The primary gas combustion byproducts that can affect indoor air quality are carbon monoxide, carbon dioxide, nitrogen dioxide, oxygen and water vapor (humidity). Today's vent-free fireplaces operate well within nationally recognized standards and recommendations for all five byproducts. American Gas Association Research Division confirms these low emission levels.
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Oxygen Detection Safety-Pilot

Since 1980, vent-free gas heating appliances have been equipped with a unique safety-pilot system called an oxygen detection safety-pilot, or ODS. The ODS is the proven technological innovation that revolutionized the safety of vent-free gas heating appliances. The ODS automatically shuts off the gas supply in the rare event that the oxygen level in the room falls to 18 percent. Until recently, questions remained about the long-term effect of vent-free gas fireplace emissions on indoor air quality. In 1995, the Vent-Free Gas Products Alliance of the Gas Appliance Manufacturers Association commissioned a study on indoor air quality as it relates to vent-free gas heating products in the home. The results proved that vent-free gas heating products meet or exceed the most current and applicable nationally recognized standards and guidelines for indoor air quality. Even so, the Hearth, Patio & Barbecue Association recommends the installation of a carbon monoxide detector with all gas hearth products.
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Direct Vent

Direct vent fireplace venting uses a coaxial pipe system (small pipe within a large pipe) and draws combustion air from the outside through the outer pipe.

An inner pipe vents the exhaust.
Can either vent out the top or out the back, for installation versatility.
Can vent horizontally through an outside wall, or vertically through the roof - no chimney required!
Ideal for adding warmth & efficient heating to a cold room.
Most are certified as gas wall furnace for highest efficiency.
Zero clearance to combustibles.
Convenient to install, space-saving depth, but requires finishing such as a mantel and surround.
Suitable for well-insulated homes or homes with no existing chimney.
Always have an enclosed front.
Best choice for newer, more air tight homes.

The Hearth, Patio & Barbecue Association recommends the installation of a carbon monoxide detector with all gas hearth products.
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Can I put a cabinet around direct vent, ventless or b-vent?

Cabinets are boxes that extend about 18" from the wall. Mantels are wood frames that only extend about 4" - 6" from the wall.
B-vent cannot have a cabinet. A b-vent fireplace must be installed in the wall, allowing all the piping to be hidden. You may then use a mantel.

Direct vents can have a cabinet if you vent piping out the back.
Vent-free can have a cabinet.

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Can I use vented gas logs in a stove? ...In a fireplace? ...In a coal burning fireplace?

Vented gas logs can only be used in a wood-burning fireplace. A coal-burning fireplace is too shallow. Vented gas logs are not recommended for a stove due to safety concerns.
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What is a chase?

A wooden structure built around the vent pipe to protect it from the weather and to keep the flue gases venting properly.
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How energy efficient is direct vent compared to b-vent?

A b-vent fireplace is the least efficient venting option and can be vented horizontally or vertically. Direct venting is the most efficient; some are even “heater rated” and can be vented horizontally, vertically or both.
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Can I use my wired wall switch or thermostat with variable high-lo logs or fireplace?

No. You have to use the remote that is designed for the high-lo variable logs or fireplaces. Return to top ^

What is a high-lo valve?

Via the remote, you will be able to raise and lower the height of the flame. The remotes are adjustable as either on off or thermostatically controlled.
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Should I buy a remote ready with vent-free gas logs?

Yes. We suggest that you get a thermostatically controlled remote so that you can keep the room at a comfortable temperature as well as turn the unit on and off. The longest lasting valve and remote are the units that vary the height of the flame.
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Can I convert my vent-free natural gas product to another fuel?

No. By national code, you cannot convert any vent-free product.
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Can I convert my vented propane gas logs to natural, or vice versa?

Yes. You can convert natural to propane and propane to natural, but in most cases, you need to buy a new valve. Your manufacturer can provide conversion instructions.
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How much can I close my damper with vented gas logs when in use?

You cannot close your damper at all with vented gas logs while they are burning.
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How can I seal my damper with vent-free gas logs?

We would recommend that you close the damper as tight as you can and get a Lock-Top damper that seals at the top of the chimney.
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With a direct vent insert, do I need to reline the chimney?

No, you do not have to reline to wood burning specifications, but you must use the piping that is recommended by the manufacturer, which vents through the existing chimney.
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What are the different kinds of burner pans for vent-free gas logs?

There is sheet metal, black pipe and stainless steel. The advantage of the sheet metal is that it is less expensive. Black pipe is heavier than sheet metal and costs a little more. The disadvantage of both is that they can rust through because they have very little rust protection. Stainless steel costs more, but will not corrode or burn through and it will last a lifetime.
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How high above the roof should a chimney extend?

The minimum clearance for wood or b-vent is 3 feet above anything within 10 feet. For direct vent it is 18 inches above anything within 10 feet.
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With direct vent or wood burning, what kind of piping do I use?

You must use manufacturer-approved piping.
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Can different piping be used if I can’t find the original manufacturer’s?

No. If you use another manufacturer's piping and it creates a problem in your home; i.e., a fire or smoke damage, no insurance company will cover you. You will also void the warranty and inspectors will not approve it.
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If brick is cracked can I burn wood?

If the crack is bigger than the tip of a graphite pencil, we do not recommend that you burn wood.
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What is the difference between an insert and gas logs?

An insert is usually a large metal box that fits into the opening of a wood-burning fireplace to increase its efficiency and enhance its look. Gas log sets are made to be hooked up to a gas line to simulate the look of wood logs within an existing fireplace.
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What is an insert?

Inserts are designed to enhance the operation and appearance of an existing wood burning fireplace, whether masonry or factory-built. Categorized primarily by the fuel burned for operation (natural gas, propane, EPA certified wood, pellet and coal), a fireplace insert is installed into an existing wood burning fireplace. Fireplace inserts are made from cast iron or steel and have self-cleaning glass doors that allow the dancing flames of the fire to be viewed while the insulated doors remain closed, making the fire more efficient. Many manufacturers also augment the operation of fireplace inserts by offering state-of-the-art features such as fans and thermostatic controls (depending on the fuel).
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What is the difference between an insert and a fireplace?

An insert is designed to be placed into an existing masonry or factory built fireplace. A fireplace is either masonry (not zero clearance) or factory built (zero clearance) unit built for burning wood or gas.
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What is zero clearance?

A zero clearance fireplace is a factory-built fireplace that is constructed so that it can be placed, safely, close to combustible material.
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What is the difference between natural and propane gas?

Natural gas is a lighter gas and it takes twice as much of it to get the same BTU rating as propane gas. Liquid propane gas contains 2,500 BTU's per cubic foot, natural gas contains 1000 BTU's per cubic foot. In addition, natural gas comes into your home through a pipeline from a local supplier. Propane is stored in a tank.
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What are the two kinds of gas logs?

The two kinds of logs are vented and vent-free. Within these two types, there are three kinds of materials used to create the logs: molded refractory cement, extruded ceramic clay and molded ceramic fibers. In addition to the logs, each log set generally includes a grate and a burner system.
Cement logs are best on vented units. Extruded logs are cheaper but look like spaghetti. Molded ceramic are more realistic and are best for vent-free
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Frequently Asked Questions

Venting Questions

Remote Controls

Conversion Questions

Piping, Dampers & Flue Questions

Terms

B Vent or Natural Vent