The benefits of Solar Augmented Attic Ventilation (#SAAV), explained
As with all innovative residential energy products, solar augmented attic ventilation is not well known and suffers from some serious misconceptions. On this site, we address some of those misconceptions.
Most residential attics are passively ventilated, meaning that air is heated and rises, drawing cooler air in from the soffit vents and exhausting it through either the ridge vents or vents in the roof slope. This passive ventilation serves to cool the attic and keep the attic temperature closer to the outside air temperature. This process happens in all seasons, but it is especially important during the summer because it saves energy and improves comfort.
When the summer sun hits dark shingles and heats up an attic like a greenhouse, ventilation helps keep that internal temperature from getting too high. If the attic is hot, however, the extra heat can radiate through the insulation and make the upper floors of a home uncomfortable. Air conditioning is often overwhelmed by this added heat for various reasons, including leaky ducts, poor balancing, and undersized A/C units. Fixing all of these issues can be very expensive. Augmented attic ventilation can be a low-cost shortcut to cool your attic and keep your air conditioning from being overwhelmed.
Solar augmented attic ventilation, unlike fans that are plugged into a house’s electrical supply, does not use added electricity to cool the attic (most plug-in fans use more energy moving air than they save in air conditioning, so the benefits are limited). Other ventilation solutions like wind-driven fans, or “whirlybirds,” only work when it is windy, typically not on the hottest sunny days, and tall vent stacks typically don’t augment the passive ventilation nearly enough to save on air-conditioning bills.
Solar augment attic ventilation works only when you need it, during hot sunny days, not at night or in winter (due to the almost horizontal angle of the solar panels). SAAV systems also do not cost anything to operate, as they are powered by the renewable energy of the sun. They improve comfort, as all augmented ventilation does, and they save money (between $100-$400 per year on cooling costs – depending on house size and other factors). Other benefits include longer life for shingles, which avoid being “cooked” by overheated attic temperature. Finally, augmented attic ventilation helps to build added resilience into a home, making it better adapted to extreme heat weather events, and taking pressure off the grid.
iSolar Solar Attic Fans are just the right size to avoid overventilating an attic; they are affordable; and they have been proven in utility lead pilots throughout Ontario (some 1100 homes in total). iSolar fans have been featured by renovation expert Bryan Baeulmer on Island of Bryan. And, they are retrofit kits that fit into existing vent holes, using the existing flashing, so the chance of a leak is extremely low (if installed by a professional roofer, it’s almost zero). They also have a 20-year manufacturer’s warranty.
Solar attic fans have been approved by Ontario’s Affordability Trust to be part of their residential home program.