Unvented appliances are intended to be used for supplemental heating and should not be used as a primary source of heat.  Primary heating equipment should be of the vented type.

Unvented appliances should not be installed in a bedroom, bathroom, or small room that is normally kept closed. (Exception: appliances specifically designed and approved to be installed in these areas may be permitted upon ERPUD review and approval.)

Unvented appliances should not be installed in high traffic areas, dusty, drafty, or windy areas.

Unvented appliances should be used only with the designated fuel and are not convertible from one fuel to another.

Homes of unusually tight construction or inadequate ventilation should not use unvented appliances.

Persons who have respiratory problems, smoke heavily, or are sensitive to odors should not use unvented appliances.

The ODS (Oxygen Depletion Sensor) is very sensitive and pilot outages are not uncommon, most often due to dust or dirt blocking the pilot.

Unvented appliances produce significant amounts of water vapor that can condense on cool surfaces such as baseboards and window panes.

Installation and use should comply with the manufacturer’s instructions and no alterations or changes should be made to the equipment.