Lennox’s Signature series model in standard efficiency is home comfort excellence. This furnace incorporates two stage operation (high/low output) with a variable speed blower motor. Variable speed fans are more electrically efficient when compared to standard fan motors and lend to better home comfort. In addition, this furnace offers more feature-rich software, so that when you combine it with Lennox’s iComfort thermostat, you will have features you would otherwise not have (e.g., a diagnostic alert system to indicate when there’s a problem with the furnace and what it is, WiFi, etc.). If you want the best within the standard efficiency group, this is the choice.