As for the commercial sector, almost every central vacuum operate with two motors. The main reason is to get a greater airflow or more waterlift. In the residential sector, dual-motor units are generally used when a hose is longer than 40 feet (12.2 meters). As mentioned in this article, the longer the hose, the more power you lose, which is to be considered. Another reason for using a two-motor central vacuum could be because the unit is installed on a higher floor than the basement.
In a case like this, additional power is required to allow dust and other waste to be pulled upwards. If the floors of a home are mostly covered with carpet, a central vacuum with better suction power is also a better option.
However, an additional motor means additional power as well. Most of the dual-motor models needs to be connected to a 220V power outlet (even in North America). More power also means moving more air, therefore the unit will have to be connected to a muffler which will exhaust outdoors.
Now you know the reasons that could lead you to choose a central vacuum with 1 or 2 motor for your home. For more information, do not hesitate to contact us and we will be happy to help you.