Cold weather is often accompanied by a drop in humidity levels. This is why people experience trouble with static electricity more often during the winter. Fortunately, we don\u2019t often experience excessively dry winters in Eugene, and the drop in humidity usually stays within a pleasant and healthy range.<\/p>\n
However, you may have heard that a furnace dries out a home\u2019s air, potentially leading to air that is too<\/em> dry during the winter. Is there any truth to this?<\/p>\n The truth is that some types of furnaces can contribute to lower humidity levels. They don\u2019t exactly \u201cdry out the air\u201d so much as they pull more outside air into a home, and this air is usually less humid than the air inside.<\/p>\n This is a result of the working of an atmospheric combustion<\/em> furnace, which is a common type of older furnace. This kind of furnace has an open combustion chamber. The combustion chamber draws on the air in the house in order to allow the burners to work. As this air is pulled from the house, it leaves a vacuum that is filled with an influx of outside air. If this outside air is drier than the indoor air\u2014which it often is during winter\u2014it will lead to a drop in relative humidity. It also creates cold drafts.<\/p>\n Many newer furnaces do not have this problem, however, because they use sealed combustion<\/em>. A sealed combustion furnace has a combustion chamber that is closed off to the rest of the house. It draws air from the outside through a PVC pipe. This means there\u2019s no forced exchange of air with the outside. The furnace will not only keep the air from becoming too dry, it will also work at higher energy efficiency because it won\u2019t lose heat through an open combustion chamber.<\/p>\nAtmospheric Combustion and Dry Air<\/h3>\n
Sealed Combustion Furnaces<\/h3>\n