A big question homeowners often ask: is the cost of a solar attic fan is worth the investment? And how much they can save on summer air conditioning costs when installed?
Do a quick search on the internet, and you will undoubtedly find many answers to this question. Few sources, however, back their claims up with scientific studies and data.
How much can you actually save?
During the hot summer months, solar attic fans help lessen the load on air conditioning systems. They do this by ventilating hot air that gets trapped inside a home’s attic. A study by the Florida Solar Energy Centre, which took place over several summer weeks in one of North America’s hottest locations, found that solar attic fans cut air conditioning usage by as much as 6 percent, and indoor temperatures by as much as 6C (~10°F). This in turn translated to savings of about 460 kw/h over the summer test period.
Electricity rates in most Canadian homes average at about $0.18 per kw/h. This means homeowners can stand to potentially save $83 each summer in air conditioning electricity costs. Because sunlight powers solar attic fans, they don’t rack up any additional electricity costs while running. During times of peak electrical demand alone, another study by the Ontario Energy Board showed that solar attic fans can save homeowners nearly 200 kw/h in electricity usage per year.
What about “negative pressure?”
One criticism of solar attic fans stems from the supposed “negative pressure” they create within a home. According to this belief, solar attic fans actually create a pressure vacuum while expelling hot air from the attic. Then, this causes even more hot air to inadvertently enter the attic. This would appear to cancel out the benefits of installing a solar attic fan.
Independent testing by Building Knowledge Canada, however, has dispelled these claims. Solar attic fans are in fact designed to work with soffit vents which regulate airflow into the home. Also, the amount of air moved by solar attic fans is not enough to create a negative pressure vacuum that sucks more warm air into the attic.
Saving you money over the long run
On top of reducing electricity usage, solar attic fans also vent trapped moisture inside a home’s attic. This prevents costly repairs down the road. If left untreated, these issues can also lead to serious health problems. They may even lead to entire homes being condemned by local authorities.
During the colder months, solar attic fans prevent ice dams from forming on a home’s eavestroughs. They do this by venting the warm indoor air that accumulates inside an attic, which would otherwise cause snow and ice to melt on a home’s roof – leading to runoff that freezes in the eaves. These in turn can lead to costly interior water damage inside when pooled runoff seeps underneath a home’s shingles and back into the home. For more information on how an iSolar Solutions solar attic fan can help your home stay cool this summer, contact our knowledgeable staff at 1-844-684-7723, or by email at info@isolarsolutions.com.
