What could happen if an unvented hearth product is not properly sized to the room?
The biggest concern is excess moisture in the home. A principal by-product of burning gas is water vapor. An unvented appliance operating at 25,000 BTU/hr will put approximately one quart of water per hour into that room! In new homes which are tightly insulated to today’s energy codes, this excess moisture can become “trapped” inside the home, condensing on cool surfaces such as window glass and frames. This in turn can lead to the development of mold and mildew which have a negative impact on the air you breathe inside your home.
