Louvres and Grilles

Air grilles, diffusers and louvres for every part of a ventilation system — supply, extract and weather protection. Alpha Air supplies wall grilles, ceiling grilles and diffusers, linear bar grilles, linear slot diffusers, external weather louvres, air valves and the grille boxes (plenums) that sit behind them, from our Leicester base. Many of our grilles are also made to measure: enter your width and height on the product page and see the price instantly, with no waiting for a quote.

Grilles for walls, ceilings and ducts

• Wall grilles — single deflection, double deflection and eggcrate grilles in stocked square sizes, plus custom made-to-order sizes and versions with an integral damper.
• Ceiling grilles — 4-way ceiling diffusers and eggcrate grilles for suspended ceilings and plasterboard.
• Linear grilles — linear bar grilles with 0, 15 or 45 degree blade profiles and linear slot diffusers from 1 to 8 slots, in standard or plaster-in frames.
• Spiral grilles — grilles designed to mount directly onto round spiral ducting.
• Air valves — supply and extract valves from 100mm to 200mm, including fire-rated versions.

External louvres and weather protection

External louvres keep weather out while letting air through — square weather louvres in stocked sizes plus rectangular weather louvres made to your exact dimensions. They are the standard termination for intake and exhaust points on external walls.

Grille boxes and accessories

Behind most grilles sits a plenum box connecting the grille to the ductwork. We stock steel grille boxes in a wide run of neck sizes and depths, plastic grille boxes, and a ceiling grid replacer for dropping diffusers into suspended ceiling grids.

Custom sizes with instant online pricing

Single deflection, double deflection and eggcrate grilles, linear bar grilles and weather louvres can all be manufactured to your exact width and height. Unlike most suppliers, we price custom grilles live on the product page — type in your size and the price appears immediately, with no waiting for an emailed quotation. Lead times for made-to-order items are shown per product; stocked grilles ordered by 3pm go out for next-day delivery, and UK mainland delivery is free over £400 ex VAT.

Which grille type goes where?

A quick guide: use double deflection grilles for supply air into occupied rooms (two rows of adjustable blades let you aim the air), single deflection grilles where one plane of adjustment is enough, and eggcrate grilles for extract, where their high free area and unobtrusive square-cell face make them the default choice. Versions with an integral opposed blade damper let you balance airflow at the grille itself rather than in the duct. On the ceiling, 4-way diffusers spread supply air evenly in all directions across the room. For long architectural runs — above windows, along bulkheads — linear bar grilles and linear slot diffusers give a continuous, clean line, with plaster-in frame versions that disappear into the wall or ceiling finish. Outside, weather louvres protect intakes and exhausts from rain while bird mesh keeps wildlife out.