You want your bathroom to be warm and humid when you step out of the shower, but you don’t want it to stay that way. All that added moisture makes an excellent breeding ground for mold (some species are toxic) and can cause rotting issues in your walls, ceiling, and framework. Here’s how to stop the problem.
Natural is Best
By far the best ventilation option is natural ventilation, which simply means having a window. It is best if the window is placed as close as possible to the main source of moisture (probably the shower), and that it’s a top opening window, since this will disperse steam more quickly. The natural light that enters through the window is the best way of killing off fungus, mildew and bacteria.
Natural ventilation isn’t always an option because many bathrooms are built against internal walls and have no window. Even if you do have a bathroom window, you might find that it’s not as effective as you’d like, or that opening it during the colder months is a big drain on your energy bills.
Ventilating your bathroom properly is extremely important.
If you’re in the midst of remodelling a bathroom, then you really do need to keep ventilation in mind while designing plans. So, what are your venting options, and how should you shop for and install the system that you need?
The only really effective option for bathroom ventilation is the installation of an exhaust fan. This is a fan that basically sucks moist air out of a room and then vents it outside.
Exhaust fans have the added bonus of also extracting smells and even smoke from a room. In general, an exhaust fan will need to be installed by a professional because it will be connected to the electricity system in your home.
In order to vent moist air an exhaust fan needs access to the outdoors. This is generally either done by building the fan into the window itself, using duct work to connect the fan to the window. Alternatively the fan can be mounted on the outside wall adjacent to the window with just a short run of duct work going through the wall to an outside louvred vent cover.
If your bathroom has no external wall then your contractor will install duct work between the ceiling joists to lead the extracted moist air to an outside wall or up through the attic of your home and out through a vent. This can make installation difficult, which is why it’s best done by a professional.
Beware of fans that vent into your roof space or crawl space. Some contractors will simply allow the fan to vent into the space between the ceiling of the bathroom and the floor above, or into the roof cavity. This is not recommended, as the damp air can cause condensation problems that will rot joists and timber in the frame of your home: an exhaust fan really does need an outside vent.
Where to Vent?
The means by which the damp air will leave your house really depends on the contractor you’re using and on your home. Many builders will not vent fans through the roof of a house, believing that roofs should never be cut unnecessarily due to leakage issues. Most installations will use pipes or ducts to carry the damp air under the floor or above the ceiling until an exterior wall is reached, and then a hole will be drilled into that wall to allow the moist air to escape.
How Large is Your Room?
When choosing a fan, you’ll need to think about the size of the room that you wish to ventilate, in order to get a fan that’s powerful enough to fully clear the room of damp air. This is fairly simple to calculate. Multiply the width, length and height of your bathroom to give you the measurement of the room in cubic metres. The building regulations governing the ventilation requirements of new homes say 15 litres per second is the minimum extraction rate for a shower or bathroom.
There are online calculators to help you to find a suitable fan. In bigger rooms you may wish to combine two smaller fans, rather than use one big one, since this will give you the option of running just one fan if the room isn’t fully steamed up and save you a little on energy bills.
Are there Other Options?
There are other choices, but really there are none as effective and cheap as installing an exhaust fan. You could use a dehumidifier in the bathroom, for example. However, this will certainly cost you more money to run than an exhaust fan will, though the initial cost of purchase and installation may be lower.
Consider a Timer
It’s a good idea to think about getting an exhaust fan with a timer or fitting a timer to the switch of the fan if possible. It’s recommended that you leave the exhaust fan on for at least twenty minutes after showering or bathing to fully clear the room. And it’s pretty easy to forget that the fan is on, and to leave it running for a far longer time, thus upping your electricity bills. A simple timer will solve this problem.
Consider a Separate Switch
The cheapest way to connect your bathroom fan is to wire it so that it comes on when the light is on. This means that in the summer the fan rarely comes on when it is needed because the bathroom light is not on. Use switches that have a neon indicator light if they are mounted outside the bathroom. The light serves as a reminder to turn it off if necessary.
There are many types of exhaust fans available, some of which combine functions. You can get a combination light and fan, or a heater and fan, or even all three elements together. You might want to think about these combined options, since they will have lower overall installation costs, and may be cheaper than buying the different elements separately.
Having decent bathroom ventilation is a must, not only for the health of your house, but for your personal health as well. It’s recommended that you have at least one window in your bathroom if at all possible. But you’ll probably find that you need to install an exhaust fan anyway. This may be a small investment, and you’ll probably need it to be professionally fitted, but in the long run, a fan is going to save you money on repair costs to your home.
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Phil Turner recently updated his bathroom and installed a pretty powerful extractor fan, complete with built-in timer. It is proving very effective at virtually eliminating all condensation problems.