What do you mean by “net energy gain” from a fireplace equipped with a Replenum Ventilator?
Although there is great variation in the design and effectiveness of fireplaces, it is generally accepted that the average open fireplace has a net energy loss when it is burned. That is, the fireplace uses more energy than it produces. This is due to the fact that an open fireplace is drawing heated room air into the fire and up the chimney, which is then being replaced (through leaks and cracks in the building) with unheated outside air. The amount of heat that the fireplace adds to the structure is usually less than the amount of heat that it will take to warm the incoming air to feed the fire. This results in the home using more energy when the fireplace is used, even though the fireplace will make some apparent heat when you sit in front of it. The Replenum Heat Recovery Ventilator changes this equation in two ways. First, the Replenum balances the amount of air going up the chimney with an equal amount of fresh air from the outside, so leakage into the building is not increased b
