Bathroom fan to renew the air in humid rooms

Most bathrooms in Spain do not have a window, especially in old buildings. Thus, the most common solution to extract bad smells and poor quality air is the bathroom fan, also known as an extractor. It is an effective and simple mechanical ventilation solution to breathe better at home and eliminate stale air  from one of the humid rooms  of the house.

In mechanical or natural ventilation systems, there is a rule regarding air renewal through extraction and admission. Although historically properties had very little airtightness and outside air filtered in, it is at least necessary to introduce and extract air for necessary renewal.

In this way, air from outside is introduced through dry rooms , either through mechanical systems -via ducts- or natural solutions, such as opening a window or having ventilation grilles  that bring in air.

In contrast, humid rooms are where extraction must take place. This is because they are where the air gets dirtier and where there may be excess humidity. For example, the kitchen is one, or the area where we do laundry. And perhaps the bathroom is the most important humid room in the home .

For this reason, using the bathroom fan in humid rooms can be one of our greatest allies to breathe quality air indoors.

Thanks to its privileged location -in an area where humidity and many odors originate-, using bathroom extractors is essential and the Technical Building Code certifies the need to install them in all homes. There are operational and construction requirements for its use to be optimized and serve better to the characteristics of each building. For example, they must be capable of operating in very high humidity conditions and be placed where there is a higher concentration of water vapor in the air.

Features of the bathroom fan in humid rooms

In the case of bathroom fans, other necessary characteristics are:

• Automation. The most common is that they are turned on via the light switch, but it can also be common to find motion sensors in, for example, public places. Other options include activation via probes or humidity meters.
• They must guarantee an acceptable noise level. Normally, bathroom extractors  can be noisier than other ventilation systems because they won’t be connected all the time, but they should not be bothersome to bathroom users. For this, the absence of vibrations is important, as it optimizes operation.
• They must be sufficiently energy-efficient. Fans must be low consumption and provide the necessary performance with minimal consumption.
• The protection index (IP) must be IP44, IP65, or IP67 depending on the location of the equipment in the bathroom.

Depending on the type of bathroom and the chosen solution, one can have axial or centrifugal fans:

1. The axial bathroom extractor  is installed in short ducts or direct installations to the facade; it is a less popular solution.
2. The centrifugal bathroom extractor  is the most common and is installed in areas where it is necessary to overcome a high pressure loss in the ducts. With a centrifugal fan, it is possible to use it in long ducts. They are installed in places where sufficient force is needed to reach the air extraction zone.

The vast majority of bathroom fans  are built with a diameter of about 100 mm, offering a flow rate of at least 60 m3/h and a pressure of 14 to 30 Pa. In large homes with larger bathrooms, it is possible to find a bathroom fan  of up to 150 mm, as long as a higher pressure is required or needs a large airflow to reach the extraction ducts.

Motors are usually low power, between 5 and 10 W if they are 100 mm in diameter. Nowadays, it is easy to find energy-efficient motors  in many of the available bathroom fan  models on the market, and they are undoubtedly the most recommended. There are also models with backdraft systems, as the problem with some old extractors is that humidity or bad odors returned when the fan was turned off. Due to their easy installation, it is recommended to have at least axial extractors in all newly built homes.