What Size Bathroom Fan Do I Need

Every bathroom in every house suffers with an backlog of wet. By their very nature, bathrooms create steam and if not removed will cause condensation on the walls and other surfaces, leading eventually to possible issues with mould, mildew and even breakdown of walls and surfaces.. The best way to address this is to remove the steam, while it is still steam. A well placed, well matched for your room extractor fan is what you need, and this department is designed to help you make the most informed pick.

Exercise you need a bathroom fan?

It is wise to accept some form of ventilation in your bath, fifty-fifty if it is just a window. However, mechanical extraction is far less random than a window, with a fan installed y'all tin can be far more certain of the unwanted air making its way exterior. Edifice Regulations office F requires that any fan in your bath must extract at to the lowest degree 15 litres per 2d (fifty/s) of air from the room. This extraction rate tin can also exist written in metres cubed per hr (m3/h), in this case, 54m3/h. At that place is no problem with your fan being more powerful than this - in fact if you have a mould trouble, it would be wise to go college – only it tin can not be lower than that.

What different types of bathroom fan are at that place?

This is where the minefield begins, but don't worry, we are here to guide you through. Extractor fans that are suitable for bath installation can be broken downwardly into three basic types:

• Axial – Designed for installation directly through an external wall, or in the ceiling on a very curt duct run, these fans are what most people will recall of when picturing a bathroom fan.

• Centrifugal – Similar wall or ceiling mounting options simply with one big difference, a centrifugal fan generates far greater pressure, making information technology capable of extracting downwards much longer duct runs. Ideal for a bathroom with no external walls. Often including more switching and operating options, Centrifugal fans can be gear up to run at a low rate so there is always some flow through the room, fifty-fifty when at that place is no-one in there.

• Inline – Every bit the proper noun suggests, an inline fan sits within the run of ducting, completely out of sight. Installed in the loft space or ceiling void above the room, an inline fan produces a much greater extraction rate which makes it ideal for installations that either accept long runs or serious condensation/ mould problems.

Are there different sizes?

When referring to a fan's "size", we're talking about the diameter of the fan blade, and in plough the diameter of the surrounding "spigot" that points into the wall or ceiling. This volition determine likewise what diameter duct pipe yous utilise, and all related grilles and accessories. Most fans come in a standard 4 inch size, which volition exist perfectly suited to 95% of domestic installations, with some offering a 6 inch variant for larger rooms which can be used in kitchens too. Axial fans tin also come in 5 inch versions, every bit tin inline fans which can go all the way up to 8 inch versions. The primary difference in all these sizes is extraction charge per unit, the larger the fan bract, the more power. The larger room you lot have, the bigger fan you volition need. This being said, in that location are less than ane% of domestic bathrooms worldwide that could not exist more than adequately extracted by a iv inch inline fan.

How practice I know what size bathroom fan I need?

Understanding what fan will conform your bathroom comes down to knowing every aspect of your installation:

• Room size – Knowing the size of your room starts to requite you a starting point of what extraction rate you lot need. To know what book of air you needs to be extracted, you have to start by knowing what the book of your room is. This is calculated by multiplying length by width by height. Permit's accept an boilerplate measurement: 3m long x 2m wide x 2.4m high = 14.4 cubic metres. This means that in order to modify the air in that room once an hour, a fan would have an extraction rate of 14m3/h. Building Regulations require rate 4 air changes per hr, and so we multiply that past 4, giving us a rate of 56m3/h or 15l/southward. The Silent Tornado's extraction rate of 97m3/h would give you half dozen.73 air changes an hr.

• Length of ducting – Every bit soon as you put a fan on any ducting, the extraction rate is affected. The air pressure within the duct will cause the air to slow as it is pushed farther away from the fan. This is where a centrifugal fan tin be useful equally they generate more force per unit area to counter the greater length of ducting.

• Installation position – Bathrooms are divided into zones depending on how close they are to the source of h2o. Which fan you lot fit will depend on what zone your are installing information technology in. More than on that in a scrap.

Which bathroom fan is all-time for my home?

Which fan is best comes again downwardly to varying factors, every home and every installation is unlike. Is your bath adjacent to a child's sleeping accommodation or is it an en-suite? Is your bath internal with no external walls? How exercise you want your fan to exist switched on and off?

Noise

How loud your fan is can be a huge determining factor for what fan you make up one's mind to buy, no-one wants to be trying to accept a relaxing bath with what sounds like a jet engine mounted in the wall. The noise level of extractor fans is displayed in dB(A) or decibels. It is worth bearing in heed that the decibel scale is not linear, and also doesn't correlate with full general perceived ideas of sound. Decibels are a measurement of sound force per unit area, not actual volume. The difference betwixt xx and 30 decibels is less in volume than the difference between 30 and 40 decibels. Have a look at this decibel comparison nautical chart to give you an idea of what decibel readings compare to.

Typical dB measurements for axial bathroom extractor fans range betwixt 35dB(A) and 45dB(A) with the more than powerful centrifugal fans betwixt 40dB(A) and 55dB(A). In recent years however the trend has moved towards even lower decibel levels. As fans become larger and the flow rate gets college, the decibel level also rises. The Silent Tornado, for example, is whisper quiet at 24dB(A). Please note that manufacturers' quoted decibel levels are taken 'at 3 metres' - This is the industry standard. Furthermore, these measurements are taken in test environments which may non necessarily replicate your installation. Likewise bear in mind that any fan activated during the night - by a telephone call to nature for example - will sound louder than during the mean solar day.

Internal bathrooms

As mentioned in a higher place, if you accept a bath that has no external walls, y'all have no pick simply to extract down a long run of duct. Near of the time this is not more three-4 metres, but it tin cease upward existence more than if the run has to go round structural elements or all the way upwardly to a roof. Centrifugal and inline fans are a bang-up solution for long duct runs thanks to the greater pressure they produce.

Switching operations

All fans maybe wired into the lighting circuit, so that they turn on and off with your lights, or a separate remote switch, assuasive them to be operated independently. Further to that, extractor fans accept a range of actress switching options which suit different applications and requirements. Many fans are available in three versions - Basic, Timer and Humidistat, only some ranges likewise take pull cord and PIR versions.

• Basic models are operated by the lite or remote switch only.

• Timer models feature a timer which keeps the fan running for a set catamenia afterward the lite or remote switch is turned off. This ensures all steam has been extracted from the bathroom.

• Fans with Humidistats volition turn on automatically when humidity in the bathroom reaches a pre-prepare level and off when the humidity falls back to its preset level. These are bully in bathrooms where the lights (and fan) are non always turned on manually and are pop with landlords, or in those installations where a fan is merely required to extract steam.

• Fans with integral Pullcord are rarer these days, only let for local operation.

• PIR (Passive Infra Red) sensors operate the extractor fan automatically when somebody enters the room.

Installing your fan

Choosing where to install your fan is a combination of electric safety and mutual sense. The beginning and nigh of import consideration is electric safety.

When plumbing equipment a fan in your bathroom, y'all must empathise which Bath Zone you are installing in. There are three bath zones, numbered 1, 2 and 3. Zone ane is basically the expanse of the bathroom or shower cubicle and upwardly to 2.25 metres loftier, Zone two is 60cm outside of Zone 1 in all directions and Zone 3 is then anywhere outside of that. Where possible, it is best to try to fit your fan in Zone i where it is close to the source of the steam. This ways the fan is extracting the steam directly out of the room as it is being produced, minimising time for it to condensate on the walls.

In social club to install a fan in Zone 1, you must adhere to IEE Wiring Regulations BS7671, Requirements for Electrical Installations Department 601 – which basically says that if you are installing in Zone 1, the fan must either be Low Voltage or IP Rated to IP45.

Low Voltage fans are powered by a 12 volt feed from a step downwards transformer, usually supplied with the fan. Although they provide a condom operating voltage in example of h2o ingress, they are a niggling more challenging to fit every bit the transformer itself must be put in Zone 3, or buried in the wall. The easiest solution for this is place the transformer above the ceiling just that isn't always possible.

A far easier solution is to install a fan that is IP rated. The IP rating arrangement basically tells you how penetrable a fitting is, perhaps a calorie-free fitting or a fan. The outset number tell you how penetrable information technology is by solid items, from something the size of a hand at ane all the way up to fully dust tight at 6 and the second number shows its resistance to liquids, with protection from h2o droplets at 1, all the way up to fully submersible at 8. A bathroom fan suitable for Zone i must be rated at IP45, although you may see information technology rated as IPX5 as the rating for solids is less important in a bathroom.

Do fans have to exist vented exterior?

When installing an extractor fan, yous must excerpt the stale air and wet to an external vent in a wall, roof tile or roof soffit. Extracting moisture and steam into a loft space volition cause mould build-up and eventually structural problems. A surface mounted axial fan will not be able to adequately excerpt outside with any real ability if the duct run is longer than iii – 4 metres.

How much does it price?

The cost of having a a bathroom fan fan installed is dependant on a couple of factors; i, Which fan you have chosen and what accessories it requires... and ii, how much your electrician will accuse to install it. A fan plus accessories should cost somewhere around £threescore - £100 depending on the fan and what bits you demand. An electrician will charge somewhere betwixt £50 and £100 for a morning'due south work, which is all a fan installation should take. Some may be a little more involved than others, you may only exist replacing an existing fan and don't need whatsoever accessories which is a half hour job; or y'all may be installing an inline fan with a long duct run and a roof tile outlet, which volition be a little more involved.

Installation tips and Troubleshooting

Every so often, a fan tin can terminate upwardly not performing how you lot expect. Quite oft, it is because of an oversight in installing or setting up the fan. Here are a few tips and tricks we take gained over the years to aid y'all.

Backdraught Shutter

A backdraught shutter can exist an invaluable addition to your installation, there'due south zippo worse than a fan that allows cold air dorsum into your bath, especially in the winter. Information technology may sound like an easy fix, but the best place to fit one is not always obvious to some installers. A lot of wall mounted centric fans these days have a backdraught device of some grade built into the back of the fan itself, but inline fans quite frequently demand one equally an additional accessory. As air travels down a duct run, it slows down. Still pushed by the air coming behind information technology, it will withal exit the exterior grille, only information technology doesn't travel as fast equally when it exited the fan itself. The trick, every bit nosotros have discovered, is to fit the backdraught shutter equally close to the frazzle end of the fan as possible. If placed closer to the exterior grille, as the air slows it will struggle to push the shutter open, creating a blockage in the duct. When placed at the frazzle end of the fan, the faster moving air pushes the shutter open more hands, making blockage much less of a problem.

Condensation Trap

Condensation traps are designed to.. trap condensation. Very simple. Understanding where is best to place them is however not so forthcoming. The first thing to empathise is that condensation traps are designed to work in vertical sections or ducting, they don't work in a horizontal duct. Although they can be used with any vertical run of duct, they are best suited to be used in conjunction with a roof tile or through roof vent to the outside world. Especially in common cold atmospheric condition, this is where steam will immediately plow to water and run straight back down the pipage. Fitting the condensation trap as close to the underside of the roof vent as possible volition be the most effective position. While a condensation trap is designed for use with solid pipework - and it is worth bearing in mind that condensation traps are for utilise with 110mm soil pipe, non 100mm duct pipe – you can use PVC ducting pipe on the underside of the condensation trap every bit it is merely well-nigh stretchy plenty to become over the larger diameter. Ducting All-time Do Horizontal ducting runs will still suffer condensation within them, although not as much. In that location are a couple of ways to combat this that are like shooting fish in a barrel to put in identify, fifty-fifty in existing installations.

• Pulling the duct so that information technology is every bit taught as possible between connection points is a really good piece of advice to go by. If there are dips and troughs in the duct, this is a perfect identify for condensation to build up and somewhen create pools of water in the duct. These pools at best restrict the diameter of the ducting, at worst can crusade ducting to rupture and spill lovely foul smelling water in your loft and through your ceiling.

• Whatever condensation occurring inside an inline fan and horizontal duct installation is more than likely to happen subsequently the fan motor, in the exhaust side of the duct run. This tin exist combatted again past having a slight downward angle to the ducting after the fan. This tin can easily be achieved by mounting the fan on a raised platform or screwed to a joist.

• Bends in ducting are often unavoidable, having to get over and effectually joists and other obstacles in your cranium or ceiling void is part of the joy of installing an extractor fan. Something to bear in mind when planning your duct run is that a 90° bend in your duct volition add together the equivalent of 1 metre of air pressure to the system. If you have a 3 metre run from fan to the exterior wall but accept two 90° bends, that's a duct run of essentially 5 metres. That's the divergence between having an centric fan and an inline or centrifugal fan installed.

Minimising Vibrations

Having an improperly fitted extractor fan in your cranium tin can be a real problem, especially if it rattles around and wakes you up in the night when someone uses the bathroom. A bully play a trick on to solve vibration with a ceiling or loft mounted fan is to mountain it on a rubber base. These can be really quite expensive for a not particularly high tech detail, and then a great installers trick is to spiral the fan downwardly onto four safety grommets that any electrician should have in abundance in the back of his van, or tin can easily be obtained from whatsoever DIY store.

Air Starvation

Ane of the single biggest reasons for calls for communication here at Extractor Fan World is when a customer has bought a more powerful fan to combat condensation in their bathroom and it notwithstanding hasn't solved the problem. This is nine times out of ten considering the fan is being starved of air, or there is poor airflow through the room. Think of it like being suffocated, as the fan is trying to take air out of the room, more than needs to come in to replace information technology, otherwise information technology'south like not beingness able to breathe. To ready this, you need to get more than air coming in when the door is shut. You can either fit a minor passive vent in the door which can exist opened and airtight as y'all need or, simply shave 5mm or and so from the bottom of the door so that more air can come in underneath information technology.