Axial Fan: Standard fan that you see mounted sometimes on ceilings, but more typically on walls, through which they are normally ducted to the outside world.
Airflow: UK extractor fan manufacturer, first incorporated in 1955. Suppliers of the famous Icon and Quiet Air fans.
Backdraught Shutter: A device which prevents draughts travelling back along a length of ducting from the outside world to the bathroom. Backdraught shutters can be simple one way sprung membranes fitted behind the impellar of a fan or electronically controlled flaps which open and close when the fan is on or off. Backdraught shutters are also stand-alone units which are installed into the length of ducting - usually near to the outside grille.
Ceiling Duct Fan: see 'Inline Fan'
Centrifugal Extractor Fan: A fan in which the impeller's blades face the direction of travel - as opposed to a standard axial fan, in which the impellar's blades . The greater air pressure generated by this design allows centrifugal fans to be ducted over very long distances - in some cases up to 50m, without significant impact on performance. This makes them ideal for internal rooms, such as office toilets, or bathrooms with damp problems. Centrifugal fans also tend to be more powerful than axial fans so are often used in larger bathrooms, north facing bathrooms or those with historical damp problems.
Condensation Trap: A valved device, mounted in a length of ducting to prevent cold condensation dripping back into the extractor fan, or through the extractor fan to the bathroom. Usually used when the fan is mounted vertically.
Ducting: Piping used to carry extracted air from the back of the fan to the outside world. Ducting comes in a number of slightly different types: Flexible aluminium is the most common for standard domestic jobs. Insulated ducting reduces condensation and is used when the duct run goes through colder areas such as a loft or ceiling void.
Extractor Fan: The term given to any device which takes air from one location and moves it to another.
Exhaust: The old/stale/moist air removed from a room.
Exhaust Spigot: Usually in reference to an inline fan, this is the spigot which 'blows' towards the outside world.
Extract Spigot: Again, usually in reference to an Inline Fan, this is the spigot which 'sucks' from the internal room.
Extraction Rate: The rate at which air is moved by the fan. The two commonly used measurements are Litres per Second (L/s) and Metres Cubed per Hour (m3/hr)
Flexible Ducting: Commonly sold in cut lengths up to 10m, flexible aluminium ducting is attached to the spigot at the back of the fan, connecting it with the outside grille. It provides a fully sealed ducting system, without which the extractor fan would not work correctly.
Grille: A ventilation duct cover which terminates a length of ducting. Available in sizes which match UK ducting (4 inch, 6, 9, 12 etc), they are avilable as either external of internal, though in practice, there is no functional difference between the two and both are made from plastic.
Heat Recovery Fan: A special type of extractor fan which utilising a basic heat exchange unit, warms incoming air with the warm extracted air to replace heat lost in the extraction process. Heat recovery units can be simple single room devices or large 'whole house units'.
Humidistat: Electronic device which measures Relative Humidity (RH) of the atmosphere. In the context of extractor fans, Humidistats are used to operate the fan. Usually they are adjustable at point of install, typically from 60% - 90% RH. Many axial fan ranges feature a humidistat model, in which the humidistat is integral to and built into the fan - such as the Tornado ST100HT. However, they are also available as separate units, designed for use with Inline Fans, which do not sit in the bathroom, and therefore could not detect the change in RH.
Inline Fan: A special type of extractor fan which sits in the middle of the duct run, usually in the ceiling, rather than on the wall. They are typically much more powerful than axial fans and can be ducted over much longer distances.
Icon: A unique extractor fan from Airflow which features an 'opening iris' back draught shutter.
L/s Litres per Second: Measurement of air movement. Typical values for a standard Axial fan are between 21L/s and 26L/s. This rises to around 60L/s for Centrifugal and Inline Fans. (see also m3/hr)
M3/hr Metres Cubed per Hour: Measurement of air movement. Typical values for a standard Axial fan are between 85m3/hr and 95m3/hr. This rises to around 240m3/hr for Centrifugal and Inline Fans. (see also L/s)
Manrose: UK manufacturer of ventilation systems and extractor fans, established in 1990.
Pull Cord. A simple device which keeps potentially wet hands away from anything eletrical and permits localised switching of the extractor fan. Pull Cord models are less popular these days and fewer manufacturers make them.
QuietAir: the name of one of Airflow's most popular products. Also known as the QT100, it was the first UK mains voltage fan to feature an IP rated electrical housing allowing it to be installed in all bathroom zones.
Remote Switch: A 'catch all' term in ventilation for any switch which is not integral to, or supplied with the ventilation unit itself. A remote switch can be a light switch or pull cord for example.
Vectaire: UK ventilation brand more known in the specification and project market than the domestic fan market.
Vent Axia - Well known UK ventilation brand offering a range of domestic and commercial extractor fans.
Whole House Ventilation System: A large ventilation system which uses a centralised extraction unit housed in, for example, the loft or large cupboard and multiple extract points in the bathrooms, bedrooms and kitchen. These systems work continuously - as opposed to common extractor fans which work as 'intermittent units' - operating at times of specific room use.
Xpelair: Established in 1960, Xpelair is one of the UK's leading ventilation brands. With a reputation for quality and having a strong presence in the specification and commercial markets, Xpelair also has a large range of domestic fans, including the VX100.