Pros & Cons of Unvented Gas Log Sets

Convenience

• Wood-burning fireplaces require considerable effort to use and maintain. Wood must be cut or purchased, loaded into the firebox and lit. Then the ashes must be cleared out after burning. The chimney and flue must be properly maintained in order to draw the smoke out of the house. Vented gas logs also require a fully functional chimney or other vent pipe. Unvented gas logs do not require venting because they are designed to burn without generating excess carbon monoxide. According to Ask The Builder, unvented gas logs that carry certification from the American Gas Association are required to have an oxygen depletion sensor that shuts off the gas supply if oxygen levels in the room drop too low.

Efficiency

• Wood-burning fireplaces are highly inefficient because most of the heat generated from burning the wood goes up the chimney. Unless an enclosed fireplace screen is installed, the flue will also draw fresh air out of the room, contributing to the inefficiency. Most vented gas logs operate at 40 percent efficiency, according to the Real Fyre website. Unvented gas logs operate at better than 98 percent efficiency. They generate more heat for less money than either wood-burning fireplaces or vented gas logs.

Concerns

• Some states and communities prohibit the use of unvented gas logs. Homeowners should check with their local codes commission prior to purchasing or installing unvented gas logs to ensure they are in compliance with local regulations. Water vapor is a by-product of burning natural gas, and unvented gas logs can produce enough water vapor to cause condensation to form on windows. Unvented gas logs may deplete the oxygen level in the room below the comfort range for people with asthma or other respiratory conditions. Since they burn natural gas, there might be a slight odor associated with the gas. Ventless gas logs require little maintenance, but if maintenance is required it must be performed by a qualified service technician.