Frequently Asked Questions

See below for the top questions we get asked about one of the most exciting innovations in the HVAC industry.

We get it - the product is new and you want to know more.  Do contact us if your question isn't answered below.

Yes, despite being new to market (since 2022) our diffusers have been installed widely across the UK, meeting with delight from all of our clients, ensuring a large percentage of re-orders.

Yes! Anywhere you are using plasterboard, you can use our diffusers. As the product have a resin binding material, they are more resilient to damp conditions than regular gypsum plasterboard.

Our products provide a flush, frameless interface with the surrounding plasterboard. When installed, they are painted the same colour as the wall or ceiling. So a better question might be "how often do you need to clean your plasterboard?". Even if the HVAC installation produces dirty air (and a well designed one won't!) the vent can be easily wiped and/or repainted if it becomes marked.

COANDA: What is the Coanda effect?

Our performance range of diffusers utilise a principle in airflow known as the Coanda effect. This phenomenon describes how a moving stream of air (or fluid) tends to curve and follow a nearby surface.

Here's a breakdown of the Coanda effect:

Airflow and Entrainment: Normally, air flowing from a source (like a Ventmann grille) mixes with the surrounding air as it travels (entrainment).

Introducing a Curved Surface: When a curved surface is placed near the airflow, it disrupts the entrainment on that side.

Pressure Difference: This disruption creates a pressure difference. The pressure on the opposite side of the jet remains higher, pushing the airflow towards the curved surface.

Curvature and Attachment: As the airflow gets closer to the surface, it curves further due to the pressure difference. Eventually, the airflow attaches itself to the curved surface and follows its shape, eventually also attaching itself to the neighbouring wall or ceiling.

The Coanda effect can be beneficial in many situations, influencing airflow patterns and potentially improving efficiency.  However, it's important to consider this effect during design to ensure optimal performance.

If you have any further questions about the Coanda effect or its application in Ventmann products, please don't hesitate to contact us.

Essentially yes. The plaster vents we supply represent just the room-facing component of the ventilation system. Fans, cooling systems and ducting are by others.

Traditional air vents have a plastic or metal grille requiring a frame that sits proud of the plasterboard surface or that is obviously a different material to the surroundings.  Ventmann frameless diffusers have no such visual impact as they are plastered-in to the surrounding surface using a light skim.  As the product is made from gypsum, the mechanical properties are the same as the wall or ceiling ensuring the final painted interface is invisible.

Our slot linear diffusers are fairly straightforward to install, but - being an innovative product - they do differ to standard grilles.  Speak to us about our online courses and approved installers list.

Assuming the required filtration is used elsewhere in the HVAC system, our diffusers make excellent medical and clean room vents and grilles due to their simplicity and ease of cleaning.

Absolutely. MVHR system are often installed in energy efficient houses where the modern design and excellent operating parameters of our vents provide a discreet solution for both supply and extract air flows.

The decibel level (dB) on our website shows the flow rates below which there is inaudible noise.  We use 17dB as the level at which we deem the flow rate to be inaudible, whereas the industry standard tends to be 25dB.  We do this to allow for other factors within the system including air flow damping and excessive velocity. 

Our linear slot diffusers come in three lengths - 625mm, 1000mm, 1250mm, with one, two or three slots and gap widths of 12mm and 18mm
Our round, square and side diffusers come in various spigot sizes of 100mm, 125mm, 160mm, 200mm and 250mm

All of our vents can be used on walls and ceilings.  We think our Side Square and Side Round diffusers look particularly stunning on walls where they can be used to produce a Coanda effect where the air flow stays attached to the surface for longer