Soffit Vent Types

Individual soffit vents come in various sizes, but most commonly in rectangular or circular shapes. Typically rectangular individual soffit vents are 4-8” in width and 14-22” in length so that they can easily be installed in between roof rafters. Circular soffit vents have diameters ranging from 1-8”, and again are installed by drilling holes in the soffit and inserting the circular soffit vents into them. Continuous length soffit vents are commonly found in 4” widths and 8 foot lengths.

An attic vent system should have a 50/50 ratio of soffit vent to roof vent to work properly. Many builders actually suggest up to a 60/40 ratio of soffit vent to roof vent. To calculate the necessary amount of attic vent required for a particular sized home or attic, see my Attic Ventilation article. Continuous soffit vent types are ideal for narrow roof eaves, however they can used on any roof eave. They should be installed the entire length of the roof eave soffit.

They can be a little tricky to install because typically two people are necessary. Sometimes they are installed in the middle of the roof eave, and other times they are installed in the very outer edge of the roof eave.

Individual soffit vent types are easier to install due to the fact that only one person is required. All that is necessary is either a jig saw or hole saw blade to cut the opening, and a screw gun to attach the soffit vent. Some older homes may not have soffit vents. Take a look around your roof eaves to determine if your home has soffit vents. Again, you should see either a long continuous perforated strip running the length of the soffits or evenly spaced individual soffit vents running the length of the soffits.

If you do not see any, or only a couple individual ones add additional ones. Inadequate soffit venting could result in ice dams, wasted energy being spent on air conditioning during summer months, and shortened roof shingle life.