The Replenum™ fireplace heat recovery ventilator prevents smoke spillage from wood-burning fire-places, while providing fresh ventilation air to the building. The Replenum system adapts a standard manufactured fireplace by installation in place of the first section of chimney, the company states. The system is designed to bring in outside air through a heat exchange chamber that picks up heat from the flue gases and delivers it to the room. A draft inducer ensures that the exhaust is always headed up and out, so no smoke spills into the room, the manufacturer says. It is fully automatic, turning on when a fire is lit and turning off when it goes out. With the addition of a timer, the Replenum can be configured to operate as a home’s ventilation system, says the manufacturer.