Sand Trap Louver vs Weather Louver: Which Does Your Intake Need?

A sand trap louver and a weather louver both sit in an exterior wall opening, but they solve different problems. A weather louver, with its angled horizontal blades, is built to block driving rain. A sand trap louver, such as Goodwind's GT-STL, uses vertical sightproof blades and a sloped sill to keep wind-driven sand out of the intake. Which one an opening needs depends on what the wind is carrying toward it.

Sand Trap Louver vs Weather Louver at a Glance

Feature	Weather louver	Sand trap louver
Main problem it addresses	Driving rain	Wind-driven sand and grit
Blade arrangement	Angled horizontal blades	Vertical sightproof blades
How it works	Blade angle blocks rain from entering the opening	Blades force the airstream to turn, and sand's inertia carries it onto a sloped sill
Typical setting	Rain-exposed exterior openings	Desert and coastal-desert exterior openings
Replaces the downstream filter?	No	No, it reduces the sand load on the filter

Why the Blade Geometry Differs

Rain and sand behave differently in an airstream, so the blade shape that works for one does not work well for the other. A weather louver's angled blades catch and shed rain. A sand trap louver instead makes the airstream change direction sharply as it passes through the vertical blades. Sand particles carry more inertia than air, so they do not follow the turn as easily. They continue on a straighter path and land on the sloped sill at the base of the unit, which is angled so the sand drains or blows back out rather than building up inside the opening.

How to Choose Between Them

For MEP Consultants at the Design Stage

Start From the Site Exposure

Look at what the site actually throws at the opening. Blowing sand and dust in a desert or coastal-desert climate points to a sand trap louver. Rain exposure without blowing sand points to a weatherproof louver. Where a site has both, say so in the enquiry so the type, material and coating can be chosen with both in mind, rather than assuming one louver covers everything.

Don't Treat the Two as Interchangeable

Several louver types look similar once installed but are not interchangeable. Name the type on the drawing and the schedule, not just "louver." Blade angle and coating should also follow from the site's exposure instead of being left as a default. Our louver guide covers the full range, and how to specify a sand trap louver lists what to put on the schedule.

For Contractors at Procurement Stage

Match the Type on the Order to the Drawing

Check that the order says sand trap wherever the drawing calls for it. A weather louver supplied in its place will fit the opening but is not designed to keep sand out.

Send Exact Opening Dimensions

Louvers are manufactured to size, so submit the exact opening dimensions instead of rounding to a standard size.

Neither Type Replaces a Filter

Both are opening protection. A sand trap louver stops coarse sand and grit at the wall, but fine dust and particulates still need to be filtered downstream, as on any HVAC intake. Our sand trap louver guide explains how the louver works in more detail, and protecting HVAC intakes from sand covers the filtration side.

FAQ

What is the difference between a sand trap louver and a weather louver?

A weather louver uses angled horizontal blades to block driving rain. A sand trap louver uses vertical sightproof blades and a sloped sill to separate wind-driven sand from the airstream.

Can a weather louver keep sand out?

It is not designed for it. Rain and sand behave differently in an airstream, so the blade shape that works for one does not work well for the other.

Do I still need a filter with a sand trap louver?

Yes. A sand trap louver stops coarse sand and grit, but fine dust still needs to be filtered downstream.

Which louver should I use where there is both sand and rain?

Selection depends on airflow requirements, weather conditions and architectural needs. Tell Goodwind the site conditions along with your opening size and airflow, and the type, material and coating can be chosen for them.

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Not sure which type fits your opening? Contact Goodwind with your opening size and airflow, or see the louver product page for the full range.