Is a ridge vent better than box vents, and when are box vents the better choice?
Short answer. On most roofs with a long, continuous ridge, a ridge vent is better: it exhausts evenly along the whole peak, has no visible hoods, and uses wind from any direction. Box vents can be the better choice when the ridge is too short or broken up to supply enough exhaust, when the ridge runs over vaulted ceilings with no attic below, or when retrofitting a ridge vent would mean replacing caps on an aging roof.
Where ridge vents win
- Long gable ridges with open attic below.
- Roofs being replaced, when the slot and vent add little labor.
- Homes where curb appeal matters, since the vent hides under caps.
Where box vents can be the better choice
- Hip roofs with short ridges: a 10 foot ridge over a 2,000 square foot attic cannot supply enough exhaust. Several box vents high on the slopes can.
- Broken ridgelines: roofs cut up by dormers, gables and towers may have short ridge segments over separate attic pockets. Box vents can be placed exactly where each pocket needs them.
- Ridges over vaulted ceilings: where the peak sits above a cathedral room without vent channels, a ridge slot vents nothing.
- Older roofs not being replaced: adding a few box vents to an attic that already has them may be simpler than cutting a ridge and buying caps that will not match.
Rules for either choice
- Use one exhaust type per attic.
- Place box vents within 3 feet of the ridge, measured vertically.
- Match exhaust to intake, never the other way around.
- Choose sturdy metal box vents in hail country.
The full comparison is in ridge vent vs box vents, and the sizing math in roof ventilation basics.