In essence, all ventilation is about circulating air to keep it fresh (cooler) and to reduce moisture levels. Attic ventilation helps to cool your attic in the summer and to remove excess water vapor in winter. There is some disagreement over attic ventilation – but this arises from the fact that there is a tremendous variation in climates across North America. The American Institute of Architects estimates that 90 percent of homes in the U.S. have unacceptably high levels of moisture. By understanding whether your home could benefit from some form of attic ventilation you may be able to increase the comfort of your home and extend the life of your roof, insulation and any other components in the attic.
When the heat from the sun strikes a roofs surface the temperature increases. Roof materials are often poor reflectors. The shingles and roof deck are heated and transfer (radiate) this heat to the other side of the roof – your attic. The insulation on your attic floor then begins to become saturated with heat in the same manner the roof was. Heat is then passed through the ceiling and into the interior of the home below the attic. Like the ceiling, walls and ceilings radiate heat and have a direct influence on the comfort level in the home and increased energy costs.
Preventing moisture damage is a much greater benefit that comes from attic ventilation and applies to colder climates more than warmer ones. In fact, the colder the climate, the more likely it is that your home will benefit from attic ventilation. As stated above 90% of homes have moisture problems. In extreme cases where the attic is unvented moisture rising up through the house condenses in the attic, causing damage to studs, insulation, and other materials.
1. Seal the Leaks
Winter or summer it’s important to seal the leaks in your home. When supply ducts leak, the air (hot or cold) you’ve paid to condition goes into your attic and out with the attic ventilation. Heat can enter or escape the home through walls and windows not just the ceiling too! By sealing the air leaks throughout your home.
2. Attic Fans
How much ventilation do you need? Generally speaking, you need a ratio of 1:300, where for every 300 square feet of ceiling space, you need 1 square foot of attic ventilation. This is where unventilated or inadequately ventilated attics will benefit from a attic fan. Attic fans are intended to cool hot attics by drawing in cooler outside air from attic vents (soffit and gable) and pushing hot air to the outside. Again, if a home is not well sealed attic fans will pull cool (conditioned) air up out of the house, into the attic and then out of the attic. This will use more energy and make your air conditioner work harder, increasing your summer utility bill and decreasing the lifespan of the cooling unit..
There is a connection between insulation and ventilation. Efficient (High R-value) insulation increases the need for ventilation. Heavier insulation soaks up and holds more heat. Overnight cooling does not remove all the heat built up in the attic and thus the insulation, ceiling and interior of home. One might think then, to reduce the amount of insulation in the attic. That would only create problems at other times of the year. Instead, the goal is to design an attic ventilation system that effectively compensates for the additional heat gain produced by the high levels of insulation. This can be done by using an attic fan and/or by increasing the size of the ventilation hole. In short, effective attic ventilation also helps cool attic insulation. Combined with a radiant barrier it can be even more efficient or effective.
4. Radiant Barriers
Radiant barriers reflect 95% – 97% of the radiant energy (hot/cold air) that comes in contact with it. Thus keeping the insulation below it relatively unaffected by the temperature of the attic. This keeps your home cooler in the summer and warmer in the winter. If you have a radiant barrier on top of the insulation it’s important that it is perforated throughout so that water vapor does not condense or freeze on the barrier’s underside damaging the insulation and ceiling. A perforated radiant barrier and properly vented attic allows moisture to escape.
In Conclusion when thinking about improving the energy efficiency and comfort of your home think about your doors, windows, crawl space, ducts, ceilings, insulation, radiant barrier, fans and ventilation. What materials are they made of, are they sealed properly and are they in the right place? These are just a few of the questions to ask? Attics are complicated systems made up of many components of which ventilation is one part. According to Thurston Energy “Your house works as a system: the heating and cooling equipment controls the temperature of the air, your ducts or fans move air around, your insulation and air sealing keeps warmth or coolness inside the living space, and ventilation brings you fresh air. They all work together.” For maximum efficiency and effectiveness ensuring that each component is addressed will make the whole system more effective.
Smart Energy Today, Inc.™ is a certified installer of attic fans, traditional insulation, radiant barriers and a variety of efficient solar products. The company features a solar powered attic as part of it’s Smart Air Ventilation™ product line.
Smart Energy Today, Inc.™ is located in Olympia and serves all of Washington, Oregon, Idaho, California and Pennsylvania. The company specializes in products that are durable and maintenance-free, saving you money and making your home or business warmer in the winter and cooler in the summer. Smart Energy Today, Inc.™ is proud of its superior products and service and always strives for positive customer reviews.