Ventilation of roof attics is required in colder climates to reduce problems created by moisture condensing on surfaces when temperatures drop. Moisture within an attic that condenses can lead to rotting structures, and damage to the interior of the house or building. Formation of ice dams can be reduced or eliminated by maintaining the attic temperatures below zero degrees Celsius, in most situations ventilation of the attic and good insulation can achieve this. In warmer climates ventilation allows heat to escape from the roof cavity, which reduces heat transferred into living spaces and can reduce energy needs.