Should a ridge vent be on my home?
Short answer. A ridge vent is a good fit for most homes with a conventional vented attic, a ridge long enough to provide the exhaust area the attic needs, and soffit or edge intake to feed it. It is a poor fit for hip roofs with very short ridges, cathedral ceilings without vent channels, sealed spray foam attics, and homes where no intake can be added.
Good candidates
- Gable roofs and long ridgelines over an open attic.
- Homes with continuous soffits along the eaves.
- Owners who want a clean roofline without rows of box vents.
- Replacement projects, where cutting the slot adds little cost.
Poor candidates
- Hip roofs with a short ridge: a 10 foot ridge over a large attic may not provide enough exhaust area, so static or off-ridge vents may be needed, following the manufacturer's guidance.
- Vaulted or cathedral ceilings: each rafter bay needs its own clear channel from eave to ridge, or the vent only serves the bays that connect.
- Spray foam or conditioned attics: designed to be sealed, so no ridge vent.
- No intake: a ridge vent without intake draws house air, adding humidity and energy cost.
Quick self-check
- Estimate the ridge length in feet.
- Estimate the attic floor area in square feet and multiply by 0.24. That is roughly the exhaust area needed, in square inches, for a balanced system.
- Divide by the vent's rated net free area per foot, often somewhere around 12 to 18 square inches. If the answer is longer than your usable ridge, a ridge vent alone will fall short.
Example: a 1,500 square foot attic needs about 360 square inches of exhaust, or 20 feet of a vent rated at 18. See ridge vent vs box vents and roof ventilation basics.