Navien’s New 2-Stage Furnace Boasts 96% AFUE

Navien has introduced a new gas furnace, the NDF600, with a 96% AFUE rating — a measure of how much fuel gets turned into usable heat, so 96% means very little energy is wasted. The furnace runs in two stages, meaning it can adjust its heat output to match how much the house actually needs, rather than blasting on and off at full power. Navien says this leads to fewer temperature swings and quieter operation compared with older single-stage furnaces. It also uses a variable-speed blower motor, which can run at different speeds instead of just on or off.

The NDF600 comes in five sizes, from 50,000 to 105,000 Btuh, so it could fit homes of different sizes and heating needs. It's also built to work alongside a heat pump as part of a dual-fuel setup, where the heat pump handles milder weather and the furnace kicks in during colder stretches. Navien notes it's certified for high-altitude installations as well, and it can pair with the company's air conditioners and coils to form a matched heating and cooling system.

This is a product announcement rather than a rebate or policy change, so there's no deadline or incentive tied to it. If your current furnace is aging or you're weighing a high-efficiency replacement, this gives you another option to ask about, with efficiency and installation flexibility as its selling points.