
Attic Insulation Ventilation Balance
Proper attic insulation and ventilation go hand-in-hand to keep your home comfortable year-round and to reduce energy bills. Ventilation helps to manage extreme temperatures in the attic and prevents moisture buildup. However, if your attic is not properly ventilated, warm air can radiate down into conditioned spaces of your home, which leads to higher heating and cooling costs.
To avoid this, the commercial insulation Residential Code (IRC) requires a certain amount of intake ventilation in the soffit area of your roof to match exhaust venting in the ridge area. Ventilator size and location are key factors that influence attic ventilation performance. Owens Corning researchers used computer simulations to investigate the effect of different combinations of these factors on attic temperatures in a typical gabled attic with a 4:12 roof slope and R-30 insulation.
Insulation Solutions for Small Spaces: Maximizing Efficiency in Tight Areas
Results showed that when the ridge-to-soffit vent ratio is smaller than recommended, the mainstream flow of ventilating air is expected to weaken along the roof bottom, while a portion will follow a detoured zigzag path characterized by three convection cells: a clockwise swirling cell near the soffit vent; a counterclockwise one occupying more than half the attic space; and another counterclockwise vortex located under the ceiling. The lower main stream travels less distance and the temperature gradient across the attic is much more pronounced than in balanced ventilation scenarios with larger ridge-to-soffit vent sizes.
The research also indicates that when the ridge-to-soffit ratio is significantly bigger than recommended, the main stream of venting air may be confined to the lower attic area, with little or no ventilation occurring in the eave areas or the upper roof area. This type of unbalanced ventilation may lead to the accumulation of excess heat in the attic and a negative pressure that can suck conditioned air from your living spaces – wasting energy, reducing comfort and causing costly damage to your home and furnishings.
Insulation Panama City
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