ventilation board

Indoor Vent vs. Outdoor Vent – Which One Costs You More in the Long Run?

Indoor vent costs half what outdoor one does. Same look. Same honeycomb. Same size. Not the same life.

Indoor? Aluminum. Foam gasket. Plated screws. Outdoor? Stainless. Silicone or beryllium copper gasket. Stainless screws.

One for air‑conditioned rooms. One for rain, salt, UV, heat, cold.

Indoor vent doesn't see rain. Doesn't see salt. Doesn't see sun. Outdoor vent sees all of it. Every day.

Aluminum hates salt. White powder grows. Powder doesn't conduct. Shielding drops. Aluminum in salt fog test: loses about 15 mg per square foot in 30 days. Fine indoors. Outside? Salt spray never stops.

316L stainless has molybdenum. Fights chlorides. Corrosion rate about 0.01 mm per year. Some stainless passes 2,000‑hour salt fog. No rust.

Gasket goes first. Indoor vent uses foam. Foam hates heat, hates UV. 70‑80°C and it hardens. Sunlight and it cracks. Outdoor vent uses silicone. Stays flexible. Or beryllium copper. No rubber to rot.

Foam dies in months. Silicone lasts 5‑10 years.

Screws. Indoor uses plated steel. Rusts outside. Rust gets into frame. Lifts gasket. Leaks. Outdoor uses stainless. Doesn't rust. Plated steel rusts in a year. Stainless lasts forever.

Temperature. Indoor vent sees 10‑40°C. Outdoor sees -40 to +70°C. Aluminum expands more than stainless. We tested it. Indoor vent, 100 cycles from -20 to +60. Frame bowed 0.5 mm. Shielding dropped 20 dB. Outdoor stainless version? 500 cycles. No change.

UV. Aluminum oxidizes. Oxide doesn't conduct. Shielding drops. Stainless doesn't care. Chromium oxide layer heals itself.

Put an indoor vent outside. 18 months max.

Three months in, gasket starts to harden. Six months, white powder at edges, screws rusting. Eight to twelve months, shielding down 20‑30 dB. Twelve to eighteen months, dead.

Outdoor vent at same site? 18 months, still looks new.

Now do the math.

Indoor vent: 50‑150 bucks. Outdoor: 200‑600.

Indoor outside needs replacement every 1‑2 years. Ten years, you buy it five times. 250‑750 in materials. Outdoor? Buy it once. 200‑600. Lasts five years plus.

Labor for five swaps. Downtime for five swaps. That costs more than the vent.

Cheap vent isn't cheap. You keep paying.

Real story. Customer in Florida. Cabinet 500 feet from ocean. Aluminum vents with foam. 18 months, shielding dropped 30 dB. White powder. Cracked gasket. Swapped to 316L stainless with silicone. Five years later, still fine.

Same spot. Same cabinet. Different material.

Indoor vent stays indoors. Server room, data center, lab. Outdoor vent goes on towers, coast, rooftops, chemical plants.

Don't put indoor vent outside to save money. You won't.

We make both. You tell us where it goes. We build the right one. That's it.