Air Intake To The Attic

See figure 2.

Air intake to the attic.

According to the national roofing contractors association nrca a power vent with an airflow rate of 1 0 cubic foot per minute per square foot of attic space measured at the attic floor is generally considered to be equivalent to a 1 150 ventilation ratio. Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. The air passes through the filter of the unit and quickly passes over the supercooled coils inside.

Attic square footage 2 square inches of exhaust and square inches of intake net free area nfa needed. Nfa is the unobstructed area through which air can pass through a vent usually measured in square inches. Ventilation manufacturers assign an nfa value to the non motorized vents they make. Warm air that escapes rooms below gets trapped in the attic.

Warm air that escapes living space also carries moisture that will condense on rafters or roof sheathing. Intake vents located at the lowest part of the roof under the eaves allow cool air to enter the attic. Having your hvac system in your attic isn t dire though you ll need to do some work to keep your air conditioner or furnace system running as efficiently as possible. Grab a flashlight and inspect your attic during the winter.

Hot air exhaust vents located at the peak of the roof allow hot air to escape. The indoor portion of your unit has an air conditioner return air intake usually located on the ceiling. This return air intake grille typically includes some type of filter to keep dust and debris out while allowing air to pass through. Snow melts and the water refreezes on the cold eaves creating ice dams.

We are going to discuss what a fresh air intake is and how a properly installed fresh air intake can increase your unit s efficiency performance and prolong the life of your furnace. When using any type of powered ventilation product for an attic application all passive attic vents will become sources for air intake. Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space. Unlike passive ventilation where air flow must travel from the lowest point in the attic to the highest powered ventilation uses air intake from all areas of the attic both high and low.

Similar to the static method adequate amounts of intake air into the attic space should be provided.