FAQ
Where does the moisture that affects an attic come from?
Houses are built much "tighter" today than they were 20 or 30 years ago. Windows are more efficient, house wraps are now commonly used, the R value of insulation has increased. Overall, our homes are more weather-tight. In doing this we trap the moisture in the home. Indoor moisture is generated by many things. The normal perspiration and breathing of a family of four adds about ½ pint of water to the air every hour. Cooking three meals a day adds four or five pints of water to the air. Each shower contributes ½ pint. In fact, every activity that uses water, (like dishwashing, mopping floors, doing laundry) adds moisture to the air. Experts say that the daily living activities of a family of four can add more than 18 gallons of water a week into the air of a home. Air moisture will flow toward drier air to equalize itself. This equalization process actually forces the indoor moisture through the ceiling and insulation into the attic area.
In attics which are not properly vented, moisture is also created by simple condensation. The air inside an improperly vented attic will be warmer than the air outside. When this warmer, moist air comes in contact with the colder roof sheathing condensation will occur. In effect, it can actually "rain" in your attic.
Can I over ventilate my attic?
The ideal ventilation system maintains the same temperature in your attic as outside or at least within 10 degrees. Minimum property standards and codes where developed in 1948. These codes were set as minimums based solely on the attic floor space. Due to the many variables in construction (roof pitches, roof color, ceiling designs), you may need to increase the amount of ventilation. Also, minimum standards may not provide an equality between intake and exhaust ventilation. Just remember if you increase the amount of exhaust ventilation – you must have an equal amount of intake. If either part of the system is unbalanced, it is better to have more intake.
What is the difference between an intake and exhaust vent?
The most important difference in an intake and exhaust vent is their location on the roof. All exhaust type ventilators are to be installed on the upper 1/3 portion of the attic area. Intake vents are generally installed in the under-eave/ overhang or fascia area.
Note: Sometimes, due to the lack of overhang-under-eave area, roof louvers are installed low on the roof and used as intake. We DO NOT recommend this due to the possibility of weather infiltration.
How difficult is it to install a ventilator?
Most consumers choose to have their ventilation system installed by a professional – cutting a hole in a roof can be intimidating to say the least. However, step by step instructions are provided for your reference.
Should I cover my turbines in the winter?
Attic ventilation systems are required year around. Most people associate attic ventilation with heat; however, of the two major destructive forces at work in your attic, moisture, not heat, is the most destructive. Since winter air is drier, it absorbs moisture from your home and you. The attic space is even more susceptible to excessive moisture in the winter. Plus when air is trapped inside the attic – it will always be warmer than the air outside. The roof sheathing/decking will be colder in winter months. Thus creating even more condensation. It can literally "rain" in your attic. This moisture produces mildew, rotting conditions damaging wood members and destroying shingles or it drips down to the ceiling below to damage plaster or paint. Insulation also becomes wet and provides less resistance to heat loss – in effect loses its R-value.
We would like to thank all participants whose joint product training in Rohlenka on 01.04.2011
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