Attic Air Flow Diagram

If your attic is well insulated the insulation might be plugging the spaces between rafters just above exterior walls.

Attic air flow diagram.

In the summer natural air flow in a well vented attic moves super heated air out of the attic protecting roof shingles and removing moisture. A different animal first think of your attic and roof as a separate entity from your home. We insulate moisture proof and throw up every barrier to heat and cold. Most updated central air conditioned homes have a new air conditioner split system meaning the ac is broken up into parts.

Whole house fans powered attic fans. These fans may be controlled by a switch or a thermostat which detects heat build up in the attic space and automatically exhausts the attic space. Fans and vents may be installed on the roof system that will draw the air out of the attic space and exhaust it to the exterior. It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow.

Well mainly it s a way to save space. Box out light fixtures. The ice traps water behind it allowing the water to seep back under the shingles and leak through the roof. Hot air exhaust vents located at the peak of the roof allow hot air to escape.

An outdoor unit which houses the fan condenser and compressor and an indoor unit which holds the evaporator and fan. Misconceptions about the air flow in your attic can lead to thousands of dollars in damage and repair costs. Water is insulation s enemy. The solution is to add baffles which allow air to flow past the insulation photo 9.

Baffles are available at home centers. That means air can t flow from the soffit vents to the roof vents. Increased ventilation will make the entire roof cold and reduce or eliminate ice dams. The insulation will resist heat transfer into the house.

In winter the natural convection air flow through the attic prevents ice. Look for water stains on the roof sheathing or damp or moldy spots on attic joists and existing insulation as a clue to where leaks might be. These ice dams form when warm attic air melts the snow on the roof and the water refreezes along the colder edge of the roof. The super heated air inside the attic can warp and damage roof shingles if not forced out through gable or roof vents.

Taking advantage of this natural process referred to as passive ventilation is the most common way to vent an attic. So why put an hvac system up in the attic at all.