Pros & Cons of Ventless Gas Logs

Installation and Appearance

• Since they require no flue, chimney or exhaust vent, ventless gas logs can be installed anywhere. However, ventless gas logs require natural or propane gas, and therefore gas lines must be run to the appliance. Unless you construct a housing for the pipes or are able to install gas lines within the wall, the gas pipes may unattractively extrude into the living area.

Attractiveness

• A warm, glowing fire with crackling, burning embers is very attractive on wintry evenings. Gas logs are constructed of sand, vermiculite and rock wool, and are shaped and painted to simulate a very realistic pile of burning logs. Manufacturers have designed a boundless variety of styles and sizes to suit every house design and space.

Regulations

• Some states forbid the use of ventless gas logs by residents. The reason for this is that ventless gas logs deplete the oxygen in the building for the fuel combustion process, and release dangerous carbon monoxide and vast amounts of water vapor into the building as by-products. Where allowed, local codes may require that the gas logs be installed only by professionally licensed installers.

Water Vapor Problems

• One of the by-products of burned gas is water vapor. With a ventless gas log appliance, the water vapor is dispersed into the building. Large amounts of unvented moisture in a building could lead to extreme condensation on windows and walls, mold and fungal growth. However, the appliance is most often used in the winter months when indoor air is extremely dry and uncomfortable. Therefore, a humid environment may be beneficial. If the home is new or air-tight, an open window will introduce fresh air and vent out some of the excess water vapor.

Oxygen Depletion and Carbon Monoxide

• All fuel-combustion heating systems, including wood furnaces and fireplaces, use oxygen for fuel and produce carbon monoxide as waste. Similarly, ventless gas logs take oxygen from the living area and exude carbon monoxide. Ventless appliances approved by the American Gas Association include oxygen depletion sensors (ODS) that constantly monitor the oxygen content in the room. In the event of dangerous oxygen depletion, the sensor will shut off the appliance until the oxygen level has risen. Additionally, ventless gas logs burn gas so efficiently that the appliance produces only small traces of carbon monoxide. Regardless, many municipalities require the added security of carbon monoxide detectors in buildings that use ventless gas appliances.

Efficiency

• Ventless gas logs are extremely efficient appliances, with some models operating at nearly 99.9 percent efficiency. In an age of energy conservation, ventless gas logs are an extremely attractive option for heating during the cold winter months. The appliances may also provide the advantage of zoning; strategically-placed fireplaces turned on in occupied rooms eliminate the wasteful heating of unused rooms and therefore reduce heating costs. Additionally, ventless gas logs require no electricity to operate; in the event of a power outage, the building would still have heat.