Attic vents are necessary to enable proper air circulation in the attic and home in general. The ventilation prevents build up of moisture or heat and maintains a convenient environment in the attic throughout the year.
In the summer, the temperatures rise considerably in absence of ventilation and can get up to 100 F in the attic. Such high temperatures force the air conditioning to work harder to lower the temperatures within the home, which in turn raises the electricity bill. These temperatures can also cause damage to the roofing and building materials present in the home in the long term. Having vents in the attic diverts this accumulated heat to the outside and keeps the internal temperatures lower.
Attic ventilation is also vital in the winter to prevent moisture buildup that occurs due to high humidity and condensation. The accumulated moisture leads to the formation of mold, usually at the underside of the roof sheathing. Further increased moisture damages the wood after a period of time and causes rotting in the long term.
Attic vents are of different types and their design is aimed at meeting particular building codes. While having attic vents is important, they have to be correctly installed; otherwise, their performance is reduced.