RHFE 556 Natural Gas/Propane 7 Stage modulating gas valve Advanced circuitry and LED controls Programmable on WTA Models Remote control on FTRA-III models Whisper-quiet fan Integral humidifier RHFE 1004 Natural Gas/Propane 7 Stage modulating gas valve Advanced circuitry and LED controls Large enough for entire home Whisper-quiet fan Integral humidifier Stainless steel heat exchanger RCE-606A Vent-Free Heater Rinnai's Silent Servant is a revolutionary vent-free convection heater aesthetically designed to fit your home's decor. It silently decides which of its seven different capacities and whisper quiet blower speeds will warm you to perfection. RCE-229A RCE-329A 99.9% Energy Efficient, vent-free Tilt switch Optional 5 year warranty 3 Year Full Warranty Whisper quiet blower Oxygen Depletion Sensor Natural or LP Gas Heats up to mid-size living areas