Navien has been pushing the boundaries of efficiency for 25 years. The NPE-240A is a result of their dedication to providing an effective and green water heating unit. The NPE-240A and all Navien models utilize condensing technology which captures additional heat lost by typical water heaters. The Navien NPE-240A's energy factor is superior to both traditional water heaters and noncondensing tankless models. Reduced vent temperatures due to this condensing technology allow you to use PVC venting, which saves you money and contributes to the ease of installation. The Navien NPE-240A has excellent technology for reducing your heating costs and carbon footprint. ComfortFlow Technology ComfortFlow is Navien's recirculation system and it is included in the NPE-240A. By combining a small insulated buffer tank with a recirculation pump the NPE-240A ensures that you will always have hot water available instantly. Help the Environment The Navien NPE-240A will reduce your home's impact on the environment.