The importance of extractor fan installation

What you know, but the client might not, is that while an extractor fan is not the most prominent of bathroom fixtures and fittings, it is one of the most important. The fan will keep the air in the bathroom fresh and help protect the space from damp and mould.

If the bathroom you’re working on has no windows, an extractor fan is non-negotiable. However, even in bathrooms that appear to be naturally well-ventilated, fitting an extractor fan can make a real difference to the quality of air in the room.

  • 1. Initial questions

    There are a few questions you’ll need answers to long before you start on installing the fan. You’ll already be running through the following points at the planning stage of any new bathroom designs, when the manual work hasn’t yet begun.

    What size and power of extractor fan do you need?

    It goes without saying that extractor fans come in various powers and sizes. A standard-sized bathroom should use a fan that extracts a minimum of 15 litres per second. If you’re working in a space larger than the average bathroom, look into getting a more powerful fan.

    Keep in mind that installing a larger fan will lead to increased noise levels. Clients might react negatively to this, so it’s worth bringing up in your planning meetings.

    Switch, remote or pull cord?

    The fan will not run constantly but will only come on at times when it’s needed. It’s entirely up to your client whether they would prefer the fan to be connected to the lighting circuit, or if they would like to be able to switch the fan on and off separately. In the latter case, the fan of course will need its own circuit.

    It could be remote-operated, or operated by a switch, which you’ll have to install in a place where you can easily run cables to meet it.

    Some clients might prefer the old-fashioned option of operating the fan using a pull cord, turning it on and off manually as needed.

    Basic, timer or Humidistat?

    You’ll have to guide your clients through the varying requirements of different bathroom designs. Together you can make a decision about whether a basic, timer or Humidistat fan is the best choice for the space.

    Choosing a basic fan might be a little less expensive. However, these fans only switch on for the duration that the bathroom light is on. You’ve probably even encountered fans that need to be turned on and off manually. This means that when no-one is in the bathroom they are not extracting any air, even when the room is humid.

    Timer fans are more efficient as they come on every time the bathroom light is switched on, then stay working for a set amount of time after the light has been switched off.

    Humidistat fans respond to sensors that detect the level of humidity in the room. When the fan is most needed – for example, when someone is showering – the fan will come on automatically. Because Humidistat fans operate independently of the electric light and are a great choice for bathrooms naturally very brightly lit.

    Where is the best place for the fan?

    Where you decide to position the fan depends upon the specific layout of the bathroom. Use your expertise to decide whether it’ll be on a wall leading to the exterior or built into the ceiling. As ever, ensure the damp air processed by the fan vents outside the building, rather than in the interior of the ceiling space, where it will cause mould.

    Also consider the placement of the cables, which is particularly important for light switch-operated fans. Dodge future problems and make sure it’s in a place where its wiring can connect easily to the lighting circuit.

  • 2. Key steps to installing an extractor fan

    The exact installation process obviously varies depending on the kind of fan you’re using and its placement within the room. However, these three steps provide an overview of the main stages likely to be involved in most simple bathroom designs.

    Step 1: position the fan

    Mark the place you plan to put the fan.

    Drill a reference hole using an extra-long spade bit. Use the hole to check the placement makes sense from both sides and also check the placement where it’ll come out, too.

    Mark out the final size of the hole needed to fit the fan and start cutting it out using a jigsaw or drywall saw. It goes without saying: remember to wear safety goggles and a respirator.

    Place the fan in the new space you’ve created, using drywall screws to secure the fan to its supportive joists. Make sure that all the connection points are correctly positioned.

    Step 2: install the duct pipe

    The duct pipe will channel the bathroom’s humid air to the outside of the building. Shorter pipes are more effective, so fans should be placed with ease of access to the building’s exterior in mind. Travelling as little as possible on its way to an exterior wall or the roof.

    Making the hole for the pipe will involve business as usual – it’s just the same processes as making the hole for the fan. As before, start with a reference hole and check the placement from both sides before continuing. If the pipe will exit through the roof, you may have to remove slates or other roof coverings.

    Step 3: finish the wiring

    You’ve already laid the cables for the fan during the first fix stage of the bathroom renovation and wired it up to the main light switch, if necessary.

    Time to bring it all together. Connect the wires in the fan unit itself to the ones you laid at that earlier stage. It always bears repeating: ensure the power is off before opening the unit. Then, it’s as simple as twisting wires of the same colour together.