Plumbing Companies
Venting is essential for two reasons. It allows air to be brought in for combustion and it helps to eliminate dangerous carbon dioxide. While it's common to have separate conduits for each, some heaters use a concentric ventilation--effectively, one pipe in the other. Concentric models, which are less expensive than PVC, can also be used. However, stainless steel is a cheaper option but it's also more expensive. Venting should be done from the top, although there are side-venting versions.