More tangible cost savings are defined when comparing the energy efficiencies of gas heaters with low NOx emissions with conventional flued types. Gas heaters with emission problems are flued and inherently lose substantial energies in the form of hot flue gases to the atmosphere. In addition, the choice of placement of flued heaters is greatly impaired due to flue installation restrictions.
In contrast, dedicated low emission gas heaters do not require a flue system. Furthermore, with the introduction of oxygen depletion sensors and thermostatic controls, they do not place critical reliance on ventilation as previously was the case. These heaters can be positioned more conveniently and centralised to affect optimum warm air distribution. By definition unflued low NOx gas heaters are 100% efficient as all heat energy released from the flame is converted to useful heat.