Extractor Fans in Bathrooms

Choosing, Installing and Maintaining a Bathroom Extractor Fan

One of the best fixtures a bathroom can have is an extractor fan. It removes excess moisture and thereby reduces mould and mildew and removes bad odours, keeping the air healthy. It should be kept in good condition, considering the conditions under which an extractor fan in a bathroom has to operate.

The door or window should be opened a little to enable the extractor fan to draw fresh air into the bathroom and replace the moist air. Without airflow into the bathroom the effectiveness of the fan will be reduced to a fraction of what it should be. After a shower the fan should run another five minutes or more. A timer switch is very handy for letting the fan work for a pre-set period after you used the bathroom, or you could install a fan with a humidistat that will do this automatically.

The fan should be placed as close as possible to the source of moisture or odour. Air should be vented all the way to the outside, because it would serve no purpose if the moist air is vented into the loft. According to the Building Code, extracted air must be directed to the outside. There are also electrical connections that may be badly affected by constant moist conditions in the loft.

Choosing an extractor fan

It's important to choose the correct fan from the start, with proper air movement capacity and silent operation, You can also use a combination of fan and light with a heat bulb or two, or alternatively a fluorescent light with the fan. Then there is the option of fan/heat/light that combines the three fixtures. The switches differ on the various models from a single switch to turn on the fan and light at the same time to switches for each function separately.

The smaller the fan the harder it has to work and the noisier it gets, so for a bathroom with a big fixture, such as a spa, you should use an appropriate fan. To determine which type of fan you would need the room must be measured by multiplying the length by the width by the height to get the volume of the room. Multiply the recommended air changes - for instance 15 to 20 times per hour for a bathroom with shower - by the bathroom volume. This will give you the cubic metres per hour air change requirement. An extractor fan with this capacity is what you would need for the job.

Axial flow fans use a propeller type blade, which are very efficient in extracting large volumes of air. Centrifugal extractor fans uses drum type blades that processes less air volumes than axial fans, but handles more pressure. Noise can really be a problem over time, so it pays to have a quiet fan installed. Some fans can be installed in the loft to make it extra quiet.

Installing a Bathroom Extractor Fan

When installing a fan, install it as far as possible from inlet/outlet grilles to prevent vibration from being transferred to the grilles, causing noise. The duct should not be too long and should be as straight as possible and must never be smaller than the fan spigot or squeezed into the spigot, as this will restrict airflow. A duct passing through an unheated roof should be insulated to reduce condensation and when using a vertical duct, a condensation trap must be fitted to release the build-up of condensation.

Be careful where you install the fan, because some zones in the bathroom are usually more moist than others and you should follow the regulations concerning extractor fans in the bathroom. A fan in the bathroom using mains voltage should always be out of arms' reach of a person using the bath or shower. These fans and controls should also be a safe distance from potential water sprays. It is better to use a low voltage fan in the bathroom and when used for the cubicle shower, a Safety Extra Low Voltage (SELV) fan.

Maintaining the extractor fan

Clean the extractor fan at least twice a year. A layer of dust can make quite a big difference on the performance of the fan. It can accumulate a lot of dust in a year, even in apparent moist conditions.

It should have a cover that can simply be pulled off or unscrewed. Remove all the dust that has been building up on the blades and also clean the vent slots. An old toothbrush or paintbrush works very well for the hard-to-reach areas.

If your duct is damaged, don't just fix it with duct tape, because it dries up and fall off over time and allows junctions and splices to open without you knowing it. You can have a carefully weather-stripped house, but if the duct is faulty then its energy and money wasted, with heated air that escapes into the loft.

"Bathrooms are particularly prone to moisture problems caused by high humidity. Heat and moisture combine to produce moisture-laden air that fills the room and, upon contacting cooler tile, walls, and ceilings, condenses, turning back into water. This feeds mold, mildew, and even structural rot. To expel humid air before it has a chance to condense, every bathroom needs ventilation. In most cases, the best ventilation for a bathroom is an exhaust fan. Though the bathrooms in most new homes are equipped with adequate bath fans, an older home is often either entirely without a fan or has one that is underpowered. When buying a new ventilation fan, be sure to check its rating for air movement, which is measured by cubic feet per minute (CFM). For an average-size bathroom, the minimal requirement is 80 CFM. Replacing an existing fan with a new one is a relatively easy do-it-yourself project as long as the new unit will fit in the existing opening and can be connected to the existing exhaust duct. Installing a new fan where there wasn’t a fan before is more involved but often easiest if you place it where there is an existing ceiling light fixture. Before you install the fan housing, the job will require cutting a hole in the ceiling at the light fixture’s location, snaking a vent pipe (or duct) from there to an exterior wall, penetrating the exterior wall for the vent, and adding a vent cap. For this job, purchase a fan that has a built-in light to replace the light you remove. If the ventwork is beyond your skill level, call in a contractor. http://www.ring4van.com"