Electric Attic Fans vs Solar Attic Fans
Attic fans may provide very significant energy savings.
Temperatures in the attic have a huge impact in
the cooling needs of the house’s rooms, and the return of the
investment provided by an attic fan is usually very short.
On the other
hand, the operational costs are very low (electric attic fans)
or close to zero (solar powered attic fans).
Note: in a
typical sunny-hot day, an electric attic fan may use 300-400
watts of energy, which corresponds to an operation cost of less
than $40 in a typical summer month.
Possible drawbacks
If there isn’t
an adequate sealing between the attic and the remaining home,
attic fans can draw air from the house, lowering energy
efficiency and even creating the risk of moisture in the attic…
Since most attic fans are mounted on the roof, that may eventually
become a source of leaks; and in a way that may also make the house more
damageable by strong winds and rains. But these are mainly
marginal hypothesis, dependent on the quality of the installation or on
very particular climate conditions. Obviously, in very windy places, with
periodic and regular very strong storms, it may be wiser not to install a
top-roof attic fan.
Benefits of solar attic fans vs. electric attic fans
Solar attic
fans dispense electrical wiring and do not need electricity. The fact that ventilation depends on
sunshine to power the fan motor is not usually a limitation,
even in cold climates, since the greatest need for ventilation
coincides with the best solar conditions and fan speed.
Disadvantages of solar attic fans vs electric fans
The price of solar attic fan is higher than that of an electric
one (around $200 more), but the dispensation of wiring and the
zero operation costs can largely compensate the higher initial
price.
Other limitations may be associated with local solar conditions,
namely in winter and cold climates, if homeowners want the solar attic
fan to fulfill uses besides cooling: in cold climates,
with few solar resources, the ventilation provided by a solar
attic fan in winter – to
fight moisture, for instance - may be insufficient, making electric powered attic
fans a more advantageous solution.
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