What is a Direct Vent Fireplace?
Here’s what you need to know
Most factory-built or “manufactured” gas fireplaces today are designed as “direct-vent” fireplaces. These energy-efficient venting systems have replaced more outdated designs, and in fact, are the primary style of fireplace installed in homes built within the last 20 to 30 years. These fireplaces are also perfect for use during a remodel or room addition, as well. Think a direct vent fireplace might be right for your home? Read on to learn more about these great products.
How does a direct vent fireplace work?
Direct vent fireplaces are fully contained fireplace units designed to draw in the fresh air and expel combustion byproducts outside the structure. There are two main types of direct vent fireplace: coaxial and colinear. The first type, coaxial, consists of a pipe within a pipe, where the outer portion serves as an intake and exhaust exits through the inner tube. The second type of direct vent fireplace, colinear, consists of two pipes in line with one serving as a dedicated intake pipe and the other serving as a dedicated exhaust pipe.
Both primary styles of direct venting provide several benefits. Each avoids issues such as oxygen starvation and poor draft. Additionally, these fireplaces perform well under strict energy efficiency requirements.
Primary features of a direct vent fireplace
Improved Venting Design
Direct vent fireplaces feature a “sealed” intake and exhaust. These units draw air from outside the home, exhaust to the outside, and radiate heat to the inside for an efficient design. Unlike traditional, or B-vent, fireplace's direct vent fireplace’s performance are not as impacted by drafts & air pressure in a home.
Venting Considerations
Direct vent metal vent pipes can be rigid or flexible depending on the needs of the installation as well as the manufacturer’s guidelines. These vents can be routed through an exterior wall, out the roof, or power-vented to go around obstacles or long distances. Additionally, no masonry chimney is required in a direct vent installation but clearances to combustibles must be maintained based on the manufacturer’s specifications.
Electrical Considerations
Most direct vent fireplaces are simply gas-powered and do not require electricity for basic operation. A standing pilot light combined with a simple & reliable millivolt valve system creates a safe design. In newer or more advanced direct vent fireplaces, a source of electricity may be required for features such as blower fans, lights, or electronic ignition systems. In addition, most new units feature an Intermittent Pilot Ignition (or IPI) that uses electricity to spark the pilot light and ignite the unit; then, after use, the pilot shuts down as well to save fuel costs as well as extinguish any standing flame.
How to install a direct vent fireplace
Are direct vent fireplaces energy efficient?
Direct vent fireplaces are energy efficient for several reasons, namely that a direct vent fireplace does not draw in heat/air from the room but rather, they are self-sufficient heating appliances. For this reason, some of these units operate with up to 70 percent efficiency. These fireplaces are also much more efficient than traditional or “decorative” vented gas logs, which lose the majority of their heat out the chimney.
How much does it cost to run a direct vent fireplace?
Typically, fireplaces are measured in terms of BTU (British Thermal Units) per hour. Natural gas users are typically billed in therms, which are equal to 100,000 BTU. Knowing this, many direct vent fireplaces are rated for between 20,000 BTU/hour and 30,000 BTU/hour, which would equate to about 1/5 to 1/3 of a therm for natural gas or gallon of propane.
As of November 2019, data collected from the U.S. government estimates the average cost per therm of natural gas is about $1.06. This puts the cost of using natural gas around 20 to 35 cents per hour. For propane users, propane is typically measured by the gallon, which is about 91,000 BTU total. Again, using data provided by the U.S. government, bulk LP costs about $2.00-$2.50 per gallon measured for 2019. That puts the cost of the fireplace units at 40 to 83 cents per hour.
Looking to add a direct vent fireplace to your home?
Call us today to speak with one of our fireplace experts. They can walk you through the buying process to ensure you find the right product for your home. Contact us for more information.
Originally published at https://www.fireplacesdirect.com on February 3, 2020.
