Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.
Best attic ventilation for florida.
Best ventilation is open soffit venting to a open vented ridge vent.
Heat rises which means it ends up in the attic.
I come across many homes that originally had soffit venting and wind turbines at the peak but continuous ridge venting was added later during a re roof.
Climate zone 1 consists of the following south florida counties.
First determine your attic area by multiplying the length by the width.
The building code lets you reduce that by half under some conditions but more roof ventilation is usually better.
Broward collier hendry lee miami dade monroe and palm beach and require a minimum r 30 attic insulation.
The code minimum for attic ventilation in the 2012 irc section r806 roof ventilation 1 is as follows.
I suspect the thinking was the more the better.
The bigger the house for whole house fans or attic space for attic venting fans the higher the cfm figure you need.
Motor power given in amps or horsepower isn t a major factor so long as it generates the required cubic feet per minute.
The typical method for ventilating the attic on an average home is soffit and ridge vent.
This means for every 150 square feet of attic floor space there should be 1 square foot of net free area.
According to the florida department of agriculture and consumer services attic insulation is the most important location and best return on investment okay but why.
Of attic floor space.
Ridge vent must me installed per the manufactures instructions.
Typically current best home building practices indicate an r 30 to r 38 for attic insulation.
Then aim for about 1 sq.
One last thought attic ventilation is not there to get rid of heat it is there to get rid of excess moisture accumulating from the home.
Insulation at least r 38 or more is there for heating and.
Of net free area for every 150 sq.
Attic for example has an area of 1 200 sq.
Intake vents located at the lowest part of the roof under the eaves.
The florida building code identifies two distinct climate zones.
I ve read where this disrupts the natural flow up from the soffits due to old turbines and new ridge vent.
Some fans are twin speed so two cfm ratings are given.
Let s say you measured your attic and you realize your attic has about 9 inches r 30 of insulation and your attic is about 40 sq feet you d need at least 3 inches of extra insulation that covers 40 sq ft to get an r value of r 38.
Proper attic insulation is the best way to prevent heat loss in the winter and retain cool air in the summer.
In of vent opening per 150 sq.