Linear Slot Diffuser - 4 Slot (Plaster-In Frame) Alpha Air

Linear Slot Diffuser – 4 Slot (Plaster-In Frame)

Plaster-in frame Linear Slot Diffuser — the concealed frame is plastered flush into the ceiling for a frameless, architectural finish. Creates long continuous runs in open areas; includes end caps and deflectors, supplied in RAL 9010. Made to order to your length.

Made to order. Please allow 7-10 working days for delivery.

Order before 3pm today for delivery by Friday 25th September

Select Size

Slots

Description

Plaster-In Frame version. The concealed frame is designed to be set into the plasterboard and skimmed flush, so the slot finishes frameless in the ceiling with no visible surround — a clean, architectural look for high-end interiors. If you prefer a conventional surface-mounted surround, this diffuser is also available with a standard frame (use the Frame selector above).

Perfect for creating long runs in large open areas, Linear Slot Diffusers are a popular choice for increasing ventilation.

Includes End Caps and Deflectors.

RAL 9010 Finish

Please note that product shown in the image is for illustration purposes only. The actual product supplied may differ in appearance, build or manufacturer. This item is made to order, and has a lead time of 7-10 working days.

Frequently Asked Questions

How do I choose the number of slots?

Slot count sets the width of the diffuser and its air-handling capacity: more slots means a wider unit that can supply or extract more air over the same length. The range runs from 1 slot up to 8 slots. If you are matching an existing installation, count the slots on the current diffuser; for new designs, your ventilation designer’s schedule will state the slot count.

What is included with the diffuser?

End caps and deflectors are included. The deflectors sit in each slot and let you direct the discharge air or blank a section off, while the end caps finish the exposed ends of the run. The diffusers are finished in RAL 9010 (white) and are a popular choice for long, clean runs in large open areas.

What is the difference between the standard and plaster-in frame?

The standard frame is designed to sit against the ceiling surface, with a visible border around the slots. The plaster-in frame version is designed to be plastered flush into the ceiling, giving a frameless, trimless appearance where only the slots are visible. Use the frame switcher on the product page to flick between the two versions at the same slot count.

Can I order a specific length?

Yes — these are made to order, and you enter the length you need on the product page. Because each diffuser is manufactured to your requirements, allow the lead time shown on the page. If you are planning a long continuous run and want advice on sections and joins, contact us before ordering.

How do I connect a linear slot diffuser to my ductwork?

Linear slot diffusers are normally fed from a plenum box behind the ceiling, which converts the slot opening to a round duct connection. Our Linear Slot Box is configured to match your diffuser’s slot count and length, with your choice of spigot positions — or contact us and we will help specify the right plenum arrangement.

Delivery Information

Made to Order

This item is made to order. Please allow 7-10 working days for delivery.

Delivery Options

Service	Estimated Delivery	Cost
Standard Delivery (UK mainland)	Next working day from dispatch	£15.95 +VAT (£7.95 for small items)
Free Delivery	Next working day from dispatch	Free on orders over £400 ex VAT
Click & Collect	Collect from our Leicester branch	Free
Scottish Highlands & Islands	2-3 working days from dispatch	£36.95 +VAT

Delivery Area

We deliver to all UK mainland addresses. Scottish Highlands and Islands deliveries may take a little longer. We are not currently delivering to Northern Ireland — Click & Collect remains available.

Questions about delivery? Call us on 0116 246 0031 or email sales@alphaair.co.uk

Returns Policy

Made to Order

This item is made to order and therefore not eligible for a return under our returns policy, unless faulty (see below).

Faulty Items

If you receive a faulty or damaged item, please let us know as soon as possible — ideally within 48 hours of delivery, so we can claim against the courier on your behalf. We will arrange a free collection and send a replacement or issue a full refund. This does not affect your statutory rights.

Questions? Contact us at sales@alphaair.co.uk