Water Heater Installation Cost
Venting is important for two reasons. First, it allows for air to enter the combustion process. Second, it removes dangerous carbon dioxide. It is common to have separate exhaust ducts, but some heaters use one vent inside another. Concentric models are typically more expensive, but PVC can be cheap. The other option is stainless steel. But again, this is more costly. Venting is typically done from the top of an unit. However, side venting is also possible.