A HVAC assembly includes a temperature mixing valve that comprises a shaft, an upper paddle, a lower paddle, and a yielding means. The upper paddle and the lower paddle attach to the shaft. The yielding means applies a force to keep the upper paddle sealed to prevent cold air in a cold air inlet from entering a mixing zone and the lower paddle moves away from a shared sealing boundary over a predetermined angle of rotation before the upper paddle initially moves to allow cold air to enter the mixing zone. Movement of the lower paddle away from the shared sealing boundary allows cold air to enter a hot air inlet and admix with hot air to mix in the mixing zone to produce non-stratified air.