Fans in the attic? The idea at first may sound odd. We usually think of fans as blowing somewhere in our home where we can feel their effects, like hanging from ceilings or mounted in windows. Few people spend more time in their attic than they absolutely must, so it seems useless to install fans there.

However, attic fans can form an important part of maintaining the overall efficiency of your air conditioning system. If you’ve taken all the steps you can to keep your HVAC system working its best (regular maintenance, duct cleaning, changing the filter, proper insulation), attic fans will take you a step beyond. We’ll explain why putting in attic fans will benefit you.

Attics are both heat traps and heat escape routes. You can use insulation to stop heat from escaping in winter, but what about summer, when heat gathers in the attic and creates excessively high temperatures that will seep into other parts of your home? (Go up into your attic on a hot day and see what it’s like. It can be miserable. You don’t want any of that to get to rooms you actually use.) To stop summer attic heat, you’ll need attic fans.

Attic fans should be wired to a thermostat that will turn the fan on based on the temperature. This saves energy since you won’t have to keep the fan on constantly or continually check on it. The movement of air in the attic will lower the high temperature.

The first benefit is the most obvious: your home will not get as hot during the summer. On average, the temperature in the attic will decrease 50 degrees with a fan, which means a drop of 10 degrees in your house.

This not only translates into comfort, it also means savings on your energy bills. A cooler house requires less work from an air conditioner to cool it. You’ll spend less, and your air conditioner will not receive extra stress that will lead to repairs and possibly an early replacement.

Attic fans will also extend the life of your roof. Rising moisture in your home will get into the roof, eventually creating mold in the insulation and the roof material. In winter, the freezing moisture can be extremely damaging. Attic fans move moisture away and keep it from settling.

High temperatures cause conductors to expand and hence increase in length. The converse is true for low temperature conditions. The change in length varies from one conductor to another depending on its thermal expansivity. The length of copper conductors, for instance, changes by 5 feet per 1000 feet of length when the conductor temperature changes from 100 – 0°, while aluminum changes by about 7 feet. The length increases with increase in temperature and reduces with reduction in temperature.

This increase or decrease in length is of great concern when installing power transmission lines between poles and towers, or when installing other power connectors. There must be an allowance for this change in length since it can cause catastrophes if it’s not there.

Weather changes are associated with increase and decrease in temperature and thus affect power transmission lines and other conductors. However, change in temperature is only one factor that affects power lines. Below are the changes that occur to power lines and other conductors as a result of weather changes:

The amount of heat dissipated from power conductors is reduced during hot and calm weather conditions. Basically, if the temperature of air around the cable is low, more heat is lost from the cable to the air. If the air is already hot, the exchange of heat is lesser. This low heat dissipation causes the lines to overheat. However, the rise in conductor temperature (overheating) worsens when cables are transmitting too much power than required. The first effect of this increased conductor temperature is snagging, which is the downward bulging of the cable between two poles, caused by the increase in the length of cables.

Snagging is largest during extreme hot weather (largest increase in temperature) conditions experienced in summer. The increase in length results to downward bulging of the cable due to the effect of gravity. Excessive sagging is dangerous if it goes below the accepted height clearance – cables could come into contact with trees, buildings and other structures underneath, causing electrocution and fires.

Excessive sagging represent an added weight on the power line and this increase may cause the line to fail or to pull down weak poles and towers. The effects can be small but gradual and so the poles and towers will finally come down or require some adjustment/replacement after some time, which is costly. This sagging can also cause the lines to short out. Excessive sagging is also costly since it leads to increased electrical resistance. This means that a sagged power line transmits lesser current than it normally does, thus causing under-feeding of electrical equipment and industries. It is also costly and time consuming to rectify a sag.