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Vairtech Double Deflection Grilles Front/Rear (Long/Short) Blades Guide

Published by

Vairtech

2026-03-19

In HVAC systems, the Double Deflection Grille is valued for its superior airflow control. As Vairtech (since 2002) , we design grilles with precision aluminum profiles and scientifically coordinated blade layers for both performance and aesthetics.

What is it?
Two layers of movable, perpendicular blades for independent airflow adjustment.

I. Which Layer is the "Long Blade"?

A grille frame has a long side and a short side.

Two standard configurations:

Front blades parallel to the LONG side
Front blades parallel to the SHORT side

Terminology:

"Long Blades" = Parallel to the grille's long side
"Short Blades" = Parallel to the grille's short side

One layer controls vertical airflow; the other controls horizontal.

II. Functional Differences

Blade Type	Primary Function	Key Application
Short Blades	Horizontal swing & diffusion angle	Left/right airflow, avoiding obstacles
Long Blades	Vertical direction & Coanda effect	Up/down airflow for seasonal comfort

Short Blades:

Adjust horizontal spread (concentrated or dispersed)
Direct air left or right around obstacles

Long Blades:

Cooling Mode ❄️: Set horizontal for ceiling attachment (prevents drafts)
Heating Mode ☀️: Tilt downward to push warm air to floor level

III. Choosing Front Blade Orientation

Front Blades	Controls	Best For
Horizontal (—)	Up/Down	High wall installs: direct air down, avoid blowing on people
Vertical ( ⎸)	Left/Right	Wide rooms/corridors: spread air across the space

Example: Bedroom Draft Problem

Outlet above bed causes discomfort. Solution: Choose horizontal front blades. Adjust to blow air along the ceiling—cool air diffuses gently, no direct draft.

⚠️ Ordering: Critical Notes

To ensure correct configuration, please specify on your order:

1. Front Blade Direction (choose one)

"Front blades: HORIZONTAL" (up/down control)
"Front blades: VERTICAL" (left/right control)

2. Installation Details (optional but recommended)

High wall / Low wall?
Primary use: Cooling / Heating?
Any special needs? (e.g., "avoid blowing on bed")

Our team will confirm settings before shipment.

Quick Summary

	Long Blades	Short Blades
Controls	Vertical (up/down)	Horizontal (left/right)
Comfort Role	Prevents drafts	Controls coverage
Cooling	Attach to ceiling	Spread air
Heating	Tilt downward	Spread air