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May 21, 2013 
/ PRODUCTS / Ventilation Basics & Benefits
There are two ovens in almost every home; 1. the kitchen cooks the food, 2. your attic cooks the house. The hot attic acts like a huge radiator, transferring heat into your living spaces, sending both utility bills and temperatures soaring. Ventilating your attic, closed spaces and storage areas is important. Proper ventilation should create continuous air circulation and helps the space maintain, as close as possible, the same ambient temperature as the outside temperature.
If you’ve ever been in your attic or enclosed spaces, you know just how hot the space can get. The sun beats down on the roof surface and heats up the stagnant air inside the attic. Most building codes require homes to have a passive vent system like ridge vents, gable vents, dormer vents, etc., but passive ventilation does not provide the pressure needed to force the air through the attic and outside. According to the Home Ventilating Institute (hvi.org), passive ventilation works via a process called ‘convection’. Convection starts at about ~128 degrees fahrenheit and to obtain true convection so that the system works properly, this requires that your attic temperature reaches an average of 138 to 142 degrees fahrenheit. Even at 142 degrees fahrenheit, assuming your air intake is balanced your system would only complete 2 to 3 air exchanges per hour which is better then nothing but not enough to keep your attic as close to the ambient temperature outside.
Reducing heat buildup which can reach 165-185° fahrenheit on hot summer days, and moisture in the winter, are the two main goals of attic ventilation.
Heat and humidity can weaken the home’s structural integrity and cause interior finish, drywall and exterior paint failures. The high cost of energy, home repairs and maintenance should be incentive enough for homeowners to properly ventilate their attics.The purpose of attic ventilation is to equalize temperatures inside and outside the attic throughout the year. In summer, this helps make the living areas beneath the attic cooler and more comfortable; this can help reduce how hard the air conditioner needs to work, thus lowering its operating costs. This counterbalance helps reduce heat that will distort and destroy roof shingles and cause the premature deterioration of roof boards, sheathing, siding and insulation. In winter, proper ventilation helps to prevent moist air, which seeps into cold areas, from condensing on the underside of the roof surface, beams and rafters. This condensation can cause mildew, rotting of wood and excessive rusting of fasteners and other metal components of the roof structure. Excess condensation creates wet insulation, which diminishes its effectiveness and in sufficient quantities may damage interior ceilings. Proper attic ventilation can also help prevent the formation of “ice dams” in the winter by equalizing the indoor and outdoor temperatures. Ice dams occur when snow hits a part of a home’s roof warmed by heat loss from the interior. The snow then melts and freezes at the eave area of the roof, where it’s colder. Here the mounds of ice and snow often drip and form icicles. That’s where a motorized fan comes in.
Benefits of utilizing a Solar Royal – Solar Ventilation unit includes:
| - Converts passive ventilation to active ventilation | - Increases the air exchanges (per hour) |
| - Reduces heat transfer resulting in cooler living spaces |
- Get a 30% Federal Tax Credit |
| - Reduces air conditioning costs | - Extends the life of your roof |
| - Removes and circulates attic heat | – Prevents ice damming |
| - Protects insulation from moisture saturation | - Fights moisture and mold build-up |
A. Size it Right |
B. Solar Orientation |
C. Proper Net Free Air Intake: |
A. Size it Right: As defined by HVI, proper ventilation is ideal with 10-12 complete air exchanges are completed each hour. By achieving these air exchanges, one should be able to get the temperature of the attic approximately 5-15 degrees fahrenheit above ambient. Please see the following calculations and verify yourself or check with your roofer, green energy audit company, builder, contractor, etc… to verify the following information in relationship to what you are looking to ventilate. (We will have automatic calculators online soon)
B. Solar Orientation: How should the solar attic fan be oriented;
C. Proper Net Free Air Intake: There are various types of intake. The Solar Royal Attic Fan moves 78’000 sqft per hour. The intake must be balanced for it to do it’s job. ~4.2 sqft of Net Free is suggested per fan.
One of the best features of a solar attic fan is the cost savings. Please note that this is only an estimate, however it gives a clear comparison of solar fans vs. electric ventilation. The figures also do not take into consideration the energy savings from keeping your attic cooler.
