In the movies you have probably seen attics as a mysterious place where treasure maps or secret stashes of gold are hidden. That is not the case in real life because in reality attics are boring and dusty, where mostly the junk of the house is kept. This includes leftover construction material, electrical wires, luggage, old photos and old clothes. But it is still important to keep the attic well-ventilated because it helps in keeping the house cool in summers and protects against the moist air that builds up in the winter season.
Attic ventilation during the winters evacuates the moist warm air that outflows from the living space in the house. If the air does not get out, it will most likely affect the roof sheathing which will further lead to rotting. You might find it odd to add ventilators to get warmth in winters but on the other hand also allow cold air to enter through the vents. But this is the key to having an energy efficient and durable home to live in. Once you allow the natural air to enter the attic to keep it cold, it will result in reducing the potential for ice damming (The snow that melts from the roof and then re-freezes in the gutters). And during the summer times, natural flow of air will prevent the house from getting super-heated and helps in removing moisture. Another way to do attic ventilation is through attic fans. This will help in cooling down hot attics by taking in air from outside from the attic vents and pushing the hot air outside. But, you need to be careful with them because if the attic is not sealed properly from the other parts of the house, it will not suck air from outside but from the cool air inside the house and move it to the attic. It will further cause your air-conditioners to use more energy, thus increasing your monthly electricity bill.
Having the right amount of attic ventilation is very important because insufficient ventilation can cause moisture problems in winters and during the summers it can lead to decreasing the energy efficiency. In the same way, too much ventilation is also bad for the house. Once you add vents, it created an extra roof penetration, thus adding another place where a leak can occur. So adding too much vents increases roof penetration and there are chances of blowouts during hurricanes.
Another advantage of attic ventilation is that it extends the shingle lie and prevents the roof from rotting. It will also reduce the repair cost as you won't have to give them much often. It prolongs the life of your roof structure and attic. Now you know how important it is to keep your attic well ventilated because it can save you from a lot of future problems and repairs. Along with that, they keep the air circulating in the house in a positive manner no matter what weather it is.