Ventilation in the bathroom - how to get it right?

Depending on how big the bathroom is, we would choose a different ventilation system. If the bathroom is small, a gravity ventilation system is enough. We are talking here about the well-known ventilation grille. Since the air from the outside should be able to reach the entire bathroom, it’s recommended to place it far from the door.

In the case of spacious interiors, or so to speak bath lounges, such a solution is insufficient as the grille won’t be able to cover it all. This is when a mechanical ventilation system is helpful. The fan in the bathroom is placed in the grille or in the exhaust duct. It can be set so that it works all the time, but most often it is turned on only when we use the bathroom, or after bathing, when the humidity level increases quite significantly. We can’t use this solution if we have a gas heater in the bathroom. The fan could suck the exhaust fumes into the bathroom and this in turn could pose a great threat to the health of the household members.

Ventilation in the bathroom can be supported by suitable doors. When it comes to the bathroom, they shouldn’t be too tight. Besides, in their lower part, they must have openings that are responsible for the exchange of air with other rooms. Rectangular openings are still the most popular, but more and more often we can find doors with round openings. They have a more subtle look and are available in many colors. If our door is solid, we should make a ventilation undercut in it, meaning slightly undercut the door leaf in its lower part. Other parameters are also important when it comes to bathroom doors. They must always open outwards, and the reveal size should be 2m high and at least 80cm wide.

Since most apartments, especially those in a block of flats, have a small bathroom, organizing its space in an ergonomic way sometimes turns out to be difficult. Ideas for small bathrooms can be found in the article “Small bathroom in a block of flats - proven tips”. With such small spaces, a gravity ventilation system is considered sufficient. But it happens sometimes that it doesn’t work effectively. The reason for that could be wrong installation, the ventilation grille may have too low capacity or be clogged, there might be no intake ventilators, and the windows could be very tight. In such cases, a mechanical ventilation system is worth consideration, just as in larger spaces.

A mechanical ventilation system provides a much better air exchange. It is important and effectively prevents mold, considering that up to 1,000g of water vapor is produced during one bath. However, there are also some downsides. When the fan is at rest, its wings impede the flow of used air. This in turn means that the gravity ventilation doesn’t work efficiently. Also, when choosing a fan, we need to pay attention to the noise level. When the appliance is on, it emits a sound, which can be a nuisance for some people, so it’s best to focus on those that work more quietly from beginning.

A ventilation system in the bathroom is mandatory by law and a bathroom without it should not be allowed to use. It could happen, however, that after buying an apartment or a house, we have to deal with such mistakes, because the contractor didn’t complete work according to construction standards and other recommendations. In such a case it’s mandatory for us to install a ventilation system. Otherwise, there is no air exchange in the bathroom, and a simple moisture absorber won’t solve the problem. It could help eliminate excess water, but only as a complement to an efficient ventilation system. So, what we should to do is contact an expert, who will tell us how to install a ventilation system in a given case.

Living in a block of flats, the investor has no control over the ventilation system installed in their apartment. Remodeling it is not allowed either. Among the most common solutions found in multifamily housing is the gravity ventilation system. The circulation is done naturally using the pressure that is inside and outside the building. However, this is not very efficient as the efficiency depends on weather changes. So, what else can a tenant do to reduce moisture?

In summer, when the efficiency of gravity ventilation system decreases, frequent airing will help. Air vents can be placed on the windows and walls. As it was mentioned earlier, ventilation undercuts of about 2.5cm in the door leaf are a good idea as well. Also, we should make sure that the temperature in the bathroom is higher than in other rooms. On one hand, using the bathroom will be more comfortable, and on the other hand, the difference in temperature will promote a better exchange of air.

The efficiency of the ventilation system depends on where in the bathroom we place the grilles and fans. The operation of the fan assumes that it will suck in used air and expel it outside. It is therefore necessary to put it in such a place where it will be able to suck in air from all or most of the bathroom. This means that it should be placed as far as possible from the air inlet - the bathroom window and door. Otherwise, it will draw in air from the outside or from the room adjacent to the bathroom.

Another important matter is its proximity to the shower unit or bathtub. This also applies to bathtubs that are fitted with a bath screen. The regulations state that a 220V appliance must be placed at least 1.25m away from an upright person taking a bath. Otherwise, there would be a high risk that the appliance gets in contact with water. A low-voltage fan, that is, one with voltage of 12V together with a transformer can be placed slightly closer. If the investor opts for a duct fan, it should be as deep in the ventilation duct as possible.

If there is a gas heater in the bathroom, the importance of efficient ventilation is even greater. If this is an instantaneous water heater, a mechanical ventilation system or a grille will do the job. It is important to remember that the ventilation grille must not be obstructed, as this would restrict the inflow of fresh air, which in this case is necessary. When burning gas, oxygen is essential. If there’s too little of it, the process can go wrong. The result is an odorless but deadly poisonous gas - carbon monoxide. Unfortunately, accidents involving carbon monoxide poisoning are not uncommon.

The thing looks different if in the bathroom there’s a dual-purpose heater with an open combustion chamber, which means that it is responsible not only for heating water but also for central heating. In such a case, in addition to the ventilation system, we should prepare an additional duct from the outside. As in the previous case, the grille in the bathroom should always be unobstructed, and it’s best to leave the bathroom door open when leaving the house. Moreover, at least once a year the grille should be cleaned, and the efficiency of the ventilation system should be inspected by a sweep.

A well-functioning ventilation system is a must in any bathroom. However, sometimes there’s still an issue with too much humidity. In such a case it’s worth reaching for a moisture absorber, which traps excess moisture. This in turn will prevent musty odor and reduce the risk of growth of fungi and mold. The smell in the bathroom will also be more pleasant and fresh. If we have a window in the bathroom, and at the same a problem with excess humidity, we can place some plants there. Not only do many species thrive in such conditions, but they also absorb excess water. This is, for example, the case with peace lily. You can learn about other plants that are good for the bathroom in our article “Plants in the bathroom”.

It’s also worth mentioning that the excess of humidity in the bathroom is influenced by the daily habits of its users. After every bath or shower we should open the window or door. Also, we shouldn’t dry our laundry in the bathroom. Even without it, this microclimate abounds in moisture.