When a new house is constructed of new materials, all these materials contain water. This includes the concrete foundation, wood framing, drywall, paint and carpet.
With new houses being built air-tight, this moisture has no where to go and can stay put and cause mold to form.
Mold in a house is bad and can lead to health problems.
A dehumidifier will remove moisture from the air. It works just like an air conditioner by cooling the air and water condenses on coils and drips into a tank. When the tank gets full the unit will shutoff so it does not overflow. The bigger the tank, the less you have to physically get up and empty the tank.
Try and find a dehumidifier that has a screw attachment for a garden hose. This will allow you to place the unit in the basement near the floor drain. Connect a small piece of garden hose to the bottom of the tank and let it flow into the drain and you will not have to worry about emptying it.
Let it run for several months after you move in. It is also recommended that you run the second floor main bathroom fan for several months to also help remove excess moisture from the house.