Bathroom Fans Guide

The most important room of any household needing an extractor fan is undoubtedly its bathroom. It is essentially needed to keep away building up of mold, humidity and above all the odor. A small four inch fan keeps the bathroom healthier by throwing out stale air and odor. These days there is a very vast variety of bathroom fans. You get them with timers, PIRs or you may opt for low energy low voltage fans and may even have a slimline and inline fan. Here we give you detailed specifications and features of different types, enabling you to choose the most appropriate.

1. Wiring regulations and Bathroom Zones

2. Extractor Type

3. Size

4. Air Extraction Rate

5. Operation

6. Noise

7. Aesthetics

Before we start, I just wanted to share this cool video with you. It’s quite informative, but what I really like is how this guy explains it all with such enthusiasm.

1. Wiring regulations

As electricity and water make a deadly combination, strict regulations are in place, dividing the bathroom into 4 zones: 0, 1, 2, 3. Zone 0 is in the bath. Zone 1 goes up vertically to a height of 2.25m above the bath. Zone 2 covers all directions for 0.6m from zone1 and zone 3 extends laterally for 2.4m from zone 2.

It is crucial to install the right fan in the right zone. Bathroom fans can work on two voltages; Mains voltage (240v) and SELV or Safety Extra Low Voltage (12v). Bathroom extractor fans working on mains should only be used in Zone 3, whereas Zones 1 and 2 should only have SELV bathroom fans (12 volt), with the transformer being kept in Zone 3. The only exception to this rule is the Airflow QuietAir: a bathroom extractor fan working on mains specifically designed with an IP45 rating that may be used in all the three zones. The other special type of 240v bathroom extractor fans are known as inline fans. These are installed in the loft space above the bathroom in the middle of two lengths of ducting. As the motor, impellers and all electrical components are beyond the zonal area, with only the duct and grille in the bathroom ceiling, they too are found suitable for being used in zone 1 or 2 above the bath or shower.

Types of bathroom extractor fans

Principally there are two types of bathroom extractor fans: Axial and Centrifugal. Axial fans are those that one often sees on walls and ceilings. They typically have an air extraction rate of 85m3/hr to 95m3/hr for a 4 inch model. These are appropriate for standard installations wherein the fan needs to be ducted through the wall. Centrifugal fans are most often inline duct fans, though exceptions are there. These fans are frequently much more powerful than their counterparts axial fans and have air extraction rates varying from 110m3/hr to 220m3/hr for a4 inch model. Centrifugal fans are principally better suited for installations needing long duct lengths. For instance The Vent AxiaSolo Plus may be employed in duct runs of up to 50m!

3. Sizes of bathroom fans

Bathroom extractor fans for domestic applications are available in two sizes: 4 inch /100mm and 6 inch / 150mm. In most of the cases a 4 inch bathroom extractor fan suffices the purpose. However for bathrooms exceeding an area of three meter square, six inch fans need consideration. At times, extraordinary circumstances also necessitate such fans; example will be a bathroom with no natural ventilation or a north facing particularly cold bathroom.

4. Air Extraction Rate

The rate at which a fan extracts out air is its most important specification. It’s measured in terms of cubic meters of air extracted in one hour or in terms of liters of air extracted in a minute.
Going by the stipulations of The Building Regulations a bathroom extractor fan must extract at least 15L/s in a normal domestic bathroom. Any 4 inch bathroom extractor fan would exceed this specification, and the present standard is 85m3/hr. A bathroom extractor fan that extracts air at the rate of 90m3/hr or above is considered powerful.

5. Operation

Bathroom extractor fans come with a range of operational features that suit different applications. The simplest one being the on/off switch via the bathroom light switch or integral pull cord. Bathroom fans with inbuilt timers are ideal for bathrooms that get large build ups of steam leading to condensation problems, as the over run timer keeps the fan running for the needed duration after it has been switched off and is especially helpful if the fan has been wired into the lighting circuit. It’s ideal to have a bathroom fan with a PIR sensor that automatically operates the fan when somebody enters the bathroom. Another good option is that of fans with humidity sensors, which get switched on automatically if the relative humidity reaches predetermined level.

6. Noise

Usually an axial bathroom fan generates noise of the level of 35dB (A) to 45dB (A), while the more powerful centrifugal bathroom fans have a noise level varying from 40dB (A) to55dB (A). Though centrifugal fans are noisier, the fact that these are housed in the loft space should not be overlooked. That way they get noise- insulated to some extent and thus reduce the level of noise.

7. Aesthetics

As you are going to use and see this fan every time and anytime you enter the bathroom, due consideration needs to be given too its looks. And, its not so expensive an accessory. Homeowners are spending big amounts to have a beautiful impressive bathroom by including modern lighting and bathroom fixtures, prompting manufacturers to design cool good looking fans that would go along the décor of any bathroom. You may even find it difficult to get that traditional box like design with grills.

I think that’s all you should know about this subject. I should have more bathroom fan reviews in the future, but I think I covered this topic in a lot of detail. Until I get some inspiration…take care.

Till about a decade or two ago, the builders and architects were not giving much thought to the designing of bathrooms. Of late, however, people are paying to get better-designed bathrooms. Yet, ventilation, a very important aspect of bathroom escapes the attention of most. We know that the bathrooms tend to be quite humid and smelly. Humidity, if not handled properly causes excessive moisture in the bathrooms and that is not healthy, neither for the bathroom nor for its users. It causes paint to peel off the walls and ceilings and rots the wooden doors or cabinets and may damage the structure too. We are aware that humid atmosphere leads to unhealthy formation of molds, mildew and bacteria.

You need to have proper ventilation to overcome this problem. Normal ceiling fans do not solve the purpose as they merely circulate air within the bathroom whereas we need to pull out stale and moisture-ridden air, making room for fresh air to come in. Then only can we expect the bathrooms to be free of odor and moisture, and free of condensation of water vapors on the mirrors.

But, an effective bathroom exhaust fan has to qualify for some standards. Here is a simple test to see if your exhaust fan is being of any good. Simply hold a piece of tissue against the grill of the exhaust fan. In case the tissue paper is tightly held against the grill, it means the fan is doing a good job. Alternatively, you may conduct the exhaust test. Just keep a plastic bag over the hood of the exhaust and switch on the fan. The bag should get filled up with air in a matter of seconds.

The capacity of an exhaust is defined by the amount of air it can pull in a minute from a given area. This is measured in terms of cubic feet per minute, CFM. A rating of above 50 is considered good for an effective and efficient bathroom exhaust fan. The Home Ventilating Institute considers an exhaust fan to be effective if it delivers 1 CFM per square foot. The capacity of the fan is in direct proportion to the area of your bathroom. Further, if the bathroom has provisions for steam rooms, sauna or hot tubs, it will need a more powerful exhaust fan. Another factor that necessitates a more powerful exhaust fan is the length of the ductwork thru which the air is thrown it. Longer lengths call for additional power.

Generally bathrooms are kept closed and are compact; a noisy fan gets unbearable when you are inside the bath. Therefore look for an elegant quiet fan that performs efficiently. Referring to HVI ratings helps to select a good fan. Over the last few years exhaust fans are designed to include accessories along with. These could include lighting and heating elements, thus getting multifunctional. Such varieties are gaining popularity.

So, while designing or renovating your bathroom do include the provision of an exhaust fan. These help to remove the odors, leaving the bathrooms smelling fresh and reduce humidity. Make sure to select a powerful exhaust fan that suits the size of your bathroom, keeping it free of moisture and unpleasant odors often encountered in bathrooms.