Monday, August 5, 2013

Vent Free VS Direct-Vent Gas Appliances


By Marge Padgitt


Many of our customers have asked us to take out their vent-free products due to a horrible smell, water running down the windows and walls, stains on walls, soot on walls, baseboards, and ceilings, mold and mildew issues, headaches, and being ill while in the house and using the logs. 

Regency direct vent insert

When burning gas several by-products of combustion are produced: Carbon Monoxide, Carbon Dioxide, Nitrogen Dioxide, Formaldehyde, and Water.

Manufacturer instructions say to use non-venting gas logs four or less hours per day and to operate the logs with a window open. Since these are listed as heating appliances and most customers purchase the logs as a heating source, this seems impractical in the middle of winter. The American Gas Association Research Division (AGARD) recommendations for proper usage of a vent-free appliance include that the appliance is not to be used as a sole source of heat or in confined spaces or bedrooms. What happens when there is a power outage? Homeowners are tempted to use the logs continuously.

During the combustion process moisture is created. When a 40,000 BTU vent-free appliance is used to heat it can produce over six gallons of water a day. If the homeowner notices condensation on windows and walls the vent-free appliance may be the cause. We call these appliances “Room Vented” for this reason. The condensation will be absorbed by the drywall, wood flooring & furniture, and may cause structural damage to the home. The excessive moisture may cause mold and mildew which creates problems for people with allergies, asthma, and other respiratory problems, or create new health problems.

The situation is worsened in tightly constructed homes without adequate make-up air to provide air for the appliances, and for people to breathe. Visit www.plusaireusa.com for more information on make-up air.

Carbon Monoxide is a very real issue. CO is always produced during combustion, and with room-vented heaters it is vented into the room at so called “acceptable' levels. Even at low levels, CO can be dangerous to children, pregnant women and their unborn babies, small children, the elderly, animals, birds, and people with upper respiratory conditions. See Dr. David Penny's website at www.coheadquarters.com for more information on CO.

Instead we suggest using a direct-vent gas log insert or fireplace. These types of appliances are vented through the wall or up an existing chimney. They are sealed systems which use outside air for combustion, thereby increasing the efficiency of the appliance and eliminating the need for opening windows while the appliance is in use. No by-products of combustion are vented into the room, so toxic gasses and water are vented directly to the outdoors. Direct-vent is a much better choice.

Vent-Free VS Direct-Vent
Vent-Free
Direct-Vent
Must operate with window open
Yes
No
Has its own combustion air supply
No
Yes
Is a High-efficiency appliance
Yes
Yes
Toxic gasses vented into the room
Yes
No
Moisture/water vented into the room
Yes
No
Can produce bad smells
Yes
No
Should have an annual service check-up and cleaning
Yes
Yes
Can be used in a masonry chimney
Yes
Yes
Can be used in a manufactured fireplace
No
Yes

 

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