 In 2019, the Department of Energy mandated a more efficient type of fan motor in all new furnaces. This well-intentioned policy is causing problems only two years later. Here's why. Your furnace fan and ductwork function the same way your heart and blood vessels do. Blood pressure should be just right, but often it isn't. If blood pressure is too high, you could have a heart attack. In your HVAC system, blood pressure is called duct pressure, which is the pressure inside the ducts. The mandated motors are far more sensitive to duct pressure than the old type. If the duct pressure inside your system is just right, it will be quiet and use very little energy compared to the old motor. If duct pressure is too high, your new, more sensitive fan motor may be overworked and die in less than three years, which can cause an expensive repair. Even if the fan doesn't die early, they are often noisy and expensive to operate. Most systems have high duct pressure and carry some risk of early failure. If you are considering replacing your HVAC system, ask for a duct pressure test from your HVAC 2.0 contractor to understand your risk and how to reduce it.