Products - Venting Primer

There are three common ways to vent propane heaters: direct vent, natural vent (B-Vent) and vent-free.

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. Some of its features are:

• 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.

B Vent or Natural Vent

This type of fireplace venting uses economical B-vent pipe for a chimney. Some of its features are:

• Uses room air for combustion and venting terminates above the roofline (like a furnace).
• More decorative, but 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 systems

Vent-Free

A vent-free gas fireplace operates without a chimney, flue or vent, so you can install one just about anywhere. Modern vent-free gas fireplaces are:

• Inexpensive and have low operating costs.
• 99 percent energy efficient.
• provide warmth during power outages.
• Design-Certified to the latest national safety standards (ANSI Z21.11.2).
• Do not exceed 40,000 Btu/hr of heat output.
• Are limited in a bedroom to 10,000 BTU.
• Can be difficult to size appropriate because code limits the size, based on the available air for combustion.

Forty-five million homes worldwide and more than eight million American homes 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. There are, however, some areas where these units are restricted. Check with your local building departments to see if a vent-free system can be used in your home.

Sealed Combustion

Sealed combustion isn't really a venting method, rather a specific design of another venting method: direct vent. But it's useful to describe here. It refers to a system in which the air you breathe is completely sealed off from the air that is bring burned. A direct vent appliance draws air from the outside, burns it, and exhausts it back out. Commonly, this is done in a way that seals the combustion air, making it a selaed combustion heater. It's important to look for a sealed combustion heater if you use any flammable chemicals in the space you're heating, or if you have athsma or other respiratory problems.