A properly functioning ventilation system is essential for good health. One of the components of ventilation is a ceiling diffuser. Air is drawn in and out through this device.
What is a diffuser
A diffuser is a part of a ventilation system designed to bring in/out air into a room and to effectively mix it. It also performs decorative functions – it closes the entrance / exit to the ventilation duct. Outwardly, it looks like an ordinary ventilation grill, but it has a slightly more complex structure, it may have additional devices – an impeller and a static pressure chamber.
The difference between a diffuser and a ventilation grille
What is the difference between a diffuser and a ventilation grille? Yes, actually, nothing. Just a ventilation grill is the simplest of diffusers. Why is the price so different? There are reasons for that.
When developing diffusers, manufacturers calculate the movement of air, position the blades and baffles in such a way that the air in the room is mixed in the best way. Therefore, the air is mixed, evenly distributed throughout the room.
Manufacturers of cheap ventilation grilles are unlikely to conduct any research, copying external features and not caring about efficiency. Air enters a certain point, there are clear zones with different temperatures. Here is the price difference.
When to Install a Diffuser
Where and when can ventilation grilles be used, and where are diffusers needed? In ordinary old-built apartment buildings, there are only exhaust ventilation ducts that work due to the pressure difference. Ventilation shaft outlets are located in the walls. In this case, you can install ventilation grilles, since the installation of a more complex device has practically no effect on the situation.
But, if you made a suspended ceiling, behind which you hid the air duct connected to this channel, it is advisable to install diffusers. They work more efficiently. Since the presence of a suspended / tension structure makes it difficult for air to move, more efficient devices are needed for the normal operation of the ventilation system.
If the ventilation system was designed specifically, you will most likely be given accurate recommendations as to what, where, what type should be. In such a situation, any replacement can adversely affect system performance.
Types of diffusers
In a store or company selling ventilation equipment, you will be offered a choice of a large number of diffusers of different appearance and materials. It is more or less easy to decide on materials – choose what you like best or what is best suited for operating conditions. If the ventilation ducts are made of metal, it is logical (although not necessary) to use metal grilles. They are galvanized, stainless steel, there are ordinary steel, but painted with powder paint.
If the ventilation ducts are made of plastic pipes, they fit better with plastic diffusers. Here, it seems, everything is clear. With the rest of the parameters a little more complicated, let’s figure it out.
Place of use
According to their purpose, diffusers are divided into:
- supply;
- exhaust;
- universal (supply and exhaust);
- combined.
The names speak for themselves: they are used in different parts of the ventilation system. Supply and exhaust differ in the direction and position of the lamellas and partitions. There is not too much difference, just some work better for air output, others for input. In principle, you can put the supply air on the hood or vice versa. The catastrophe will not happen, but the performance of the ventilation system may drop slightly. In private houses and apartments, the difference, due to low productivity, cannot be noticed. Tangible changes can only be in high-performance ventilation.
Universal diffusers pass air in both directions equally. So you can install them without hesitation. But, as usual, “station wagons” work a little worse than specially designed models.
Explanations are needed only, perhaps, with combined models. They differ in that part of the device works for inflow, part for outflow. Accordingly, they are connected to different parts of the ventilation system. That is, you can install only one universal diffuser on the ceiling, and you will need to connect it to two branches – supply and exhaust. The connection method is described in each specific model, in general it makes no sense to talk about it.
Materials
Diffusers are made from:
- plastics;
- aluminum;
- steel (plain or stainless).
In private houses and apartments, plastic is most often used. For this situation, this is the best option. At a relatively low price, they have excellent performance characteristics, long service life, easy maintenance, and are not subject to corrosion. They fit seamlessly with plastic air ducts, which are used more and more often in private homes.
Metal diffusers are used in industrial premises where only non-combustible materials can be used. They cost significantly more, weigh more, which complicates installation.
There are also diffusers, the outer part of which (grille) is made of wood. Such devices will ideally fit into the interior of a wooden house.
Location
By location, diffusers are:
- ceiling;
- wall;
- floor.
Most often you can see a ceiling diffuser. They are used in 95% of ventilation systems, both in supply and exhaust systems. Mainly because the air is mixed in the upper part of the room, without causing much discomfort to a person. And also because with the device of false ceilings it is easier to make a ventilation system, if it simply did not exist before. Most often, the devices are attached to the main ceiling, and a hole is cut out in the stretch / suspended ceiling, which is covered by the grille.
Sometimes forced ventilation is done through the basement. Then install floor diffusers. This phenomenon is very rare.
Wall diffusers are used even less frequently. There are not many situations. For example, in apartments after replacing windows with plastic ones. In this case, an influx of fresh air is needed and it can only be provided by making a hole in the wall and installing a diffuser. Or with a lack of fresh air inflow and unwillingness to build / reconstruct the supply system.
Further, he will talk about ceiling diffusers, since they are the majority, and all the others still need to be looked for – they are usually delivered to order.
Design features
Ceiling diffusers are available in different designs. There are vortex and slotted. These types can be made of any material, for any installation method. But, as agreed, we are talking about ceiling models.
Vortex
In them, the lattice partitions are located in such a way as to create turbulences of air masses. This greatly increases the speed of air mixing, increases the performance of the system. It is easy to recognize them – by the characteristic radial arrangement of the jumpers. A swirl ceiling diffuser is used where a quick air change is required. It makes sense to put them in bathrooms and toilets – to quickly restore a normal atmosphere, although they are usually used in rooms with a large area and high ceilings.
The inner part of the swirl ceiling diffuser is usually made in the form of a cylinder, and the grille can be any – round or square, but the holes in it are located strictly in a circle.
The swirl ceiling diffuser for supply ventilation may have an additional impeller, which is located behind the grille in the housing. The impeller can be movable or fixed. The movable impeller can be controlled – have several rotation speeds.
Another variety is with a static pressure chamber. It eliminates too active movement of air masses. In the case of using ventilation diffusers with a plenum chamber, even at high flow rates, there will be no drafts in the room.
Slotted
The slotted ceiling diffuser is so called because of the characteristic shape of the holes – in the form of slots. The location of the slots, the shape and dimensions of the partitions are specially designed and calculated. The distribution of air flows depends on their position and direction.
Are applied in rooms with small or average productivity of system of ventilation. They are placed in living rooms, technical rooms with normal operating conditions (dressing rooms, pantries, built-in wardrobes).
They have one important feature – there are adjustable slot diffusers that can change the direction of air supply (similar to blinds on air conditioners). If we talk about types, then they can be with or without a plenum.
The shape can be any – with a round, rectangular or square outer grille. There are long and narrow models. Such a linear slot ceiling diffuser is not very striking. In rooms of a certain design (loft, modern) they can serve as a kind of decoration.
Adjustable
To create a comfortable atmosphere in any situation and at any time of the year, there are adjustable diffusers. Sliding plates are added to their design, by turning which the throughput changes.
There is a special name for adjustable diffusers – anemostats. They are adjusted by turning the central part clockwise or counterclockwise. All slats in anemostats are movably fixed, changing their position they open/close the gap for air passage.
There are also models with built-in presence sensors and air composition analyzers. They are connected to the microclimate control system, which automatically maintains the specified atmospheric conditions. But it is part of a whole expensive system.
Ceiling diffuser: installation
There are two ways to connect diffusers to ventilation ducts: directly or through an adapter (plenum). The second option is more correct, but it requires a larger gap between the base and decorative ceiling.
If the shape and dimensions of the ceiling diffusers and ventilation pipes match
To connect the ceiling diffuser directly to the ventilation pipes (bends), a tee/splitter is placed in the ventilation pipe at the installation site. In the free – third – exit and put the device.
Cutting a hole directly in the pipe for its installation is the wrong decision. The body protrudes beyond the pipe, impeding the movement of air, the performance of the system drops, over time a dust plug is still formed, which can generally block the lumen. In general, this should be avoided.
It is necessary to select bends from the main pipe so that they can be conveniently connected to diffusers. It will not be difficult to connect a round diffuser to a round outlet from the duct, and a rectangular diffuser to a rectangular one. It is also important that their sizes match. This simple truth must be remembered when creating a system, choosing tees or making bends with the appropriate parameters.
Diffusers of the same size are installed in the ventilation ducts by simply inserting them. Models that are small in size and weight can be fixed to the box with a sealant (silicone neutral). This is how models with a round base are usually attached.
For suspended ceilings of various types (plasterboard, plastic, Armstrong), a special fixing system has been developed – Clip in. It consists of spacers of the type that can be seen on recessed ceiling lights.
More massive square / rectangular models are attached to the walls of the box with self-tapping screws or suspended from the ceiling. The first option is simpler, but it is better not to use it, since dust collects on the protruding screw of the self-tapping screw. Unless the design provides for special protrusions for fasteners. Otherwise, over time, in the place where the self-tapping screw sticks out, a solid plug is formed that interferes with the passage of air.
If the outlet is made of corrugated material or there is a desire to do everything “correctly”, heavy cases are suspended from the ceiling on studs or hangers.
Using Adapters
Adapters or plenums help to avoid such an unpleasant phenomenon as drafts. In this tank, there is a uniform redistribution of air, which flows evenly over the entire surface of the grate. But these devices have a significant drawback – they “steal” the height of the ceiling. Side connection models are smaller, but they still take up enough space.
Most often, a static pressure chamber is a parallelepiped, to the bottom of which a diffuser is attached. From above or side there is an exit for connection of a ventkanal. It can be of any required shape: circle, square, rectangle, oval.
There are adapters:
- With integrated rotary valve. If the diffuser model does not provide for adjustment, this can be done using an adapter.
- With removable filter. They also allow you to clean the incoming air.
- With airflow divider. This is a sheet of metal with a small cell. Mounted on powerful supply systems, it allows you to evenly distribute the air flow over the entire surface of the grille. .
Static pressure chambers for ventilation diffusers are made most often from galvanized steel. Sheet thickness – 0,5-0,8 mm. There are companies that will make the device according to your parameters. Also on sale there are standard adapters – for standard solutions. They can be made of steel (galvanized, stainless) or plastic.
If necessary, the static pressure chamber is sheathed with insulation. This is necessary so that when the warm surface of the adapter and cold air interact, condensation does not fall on it.
If the diffuser is connected via an adapter, the main task is to secure this device. If it is a suspended ceiling, you can mount the camera to the profiles. In the case of a stretch ceiling, you will have to hang it from the main ceiling. The methods are known: studs or perforated hangers.