The part nobody sees, and the part that decides how long the roof lasts

Why it matters more than the shingle

Proper attic ventilation helps regulate temperature and moisture, preventing mold, rot, and ice dams. A Pittsburgh winter is exactly the climate that punishes getting it wrong: warm air escapes into the attic, melts snow on the roof deck, and the runoff refreezes at the cold eave. That is an ice dam, and it pushes water backward under the shingles.

In summer the same unvented attic bakes. Trapped heat cooks the shingles from underneath and ages a roof years faster than the weather on top of it ever would.

Balanced means balanced

Ventilation is a pair, not a product. Air has to come in low at the soffits and leave high at the ridge. Add exhaust without matching intake and the system pulls its air from inside the house instead of outside it, which is worse than doing nothing. Getting that pairing right on your specific roof is what the Lomanco certification is about.