A big question homeowners often ask is whether the cost of a solar attic fan is worth the investment, and how much they can save on summer air conditioning costs by having them installed.

Do a quick search on the internet, and you will undoubtedly find many answers to this question. Few sources, however, are able to 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 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 per cent. The solar attic fans decreased indoor temperatures by as much as 6C, which in turn translated to savings of about 460 kw/h over the summer test period. 

With electricity rates in most Canadian homes averaging at about $0.18 per kw/h, this means homeowners can stand to potentially save $83 each summer in air conditioning electricity costs. Because solar attic fans are powered by the sun’s rays, they don’t rack up any additional electricity costs when they are 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 is that they supposedly create “negative pressure” within a home. The belief is that while expelling hot air from the attic, solar attic fans actually create a pressure vacuum which leads to even more hot air inadvertently entering 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. This is because solar attic fans are designed to work with soffit vents which regulate airflow into the home. Also, it was found that 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

It is important to also recognize that on top of reducing electricity usage, solar attic fans also vent trapped moisture inside a home’s attic, preventing costly repairs down the road. If left untreated, these issues can also lead to serious health problems, and 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.