Bathroom fans are essential for removing moisture and bad odors from the bathrooms in the home, preventing the formation of mold. By removing excess moisture in the air, you can also prevent wallpaper and paint from peeling off and doors and windows from warping. Installing or replacing a bathroom fan are pretty straightforward DIY projects for people with basic woodworking and electrical engineering skills. Start reading from step 1 to find out more.
Steps
Method 1 of 3: Preparation
Step 1. Determine the correct M3H value for your bathroom
The first thing you need to do when installing a new bathroom fan is to determine the M3H value for your bathroom so that you can purchase a fan of adequate power.
- M3H stands for "cubic meters per hour" and refers to how much air the fan can move per hour. Some small baths require low M3H fans, while larger baths require much higher values.
- To calculate the M3H required by your bathroom, obtain its cubage by multiplying width x length x height. For example, if your bathroom is 4.5 square meters, you should multiply this value by the ceiling height (for example 2.5m) to get 11.25 cubic meters. At this point, multiply this value by the necessary air changes per hour, which for a domestic bathroom with shower are approximately 3, to obtain the flow rate of 33.75 M3H for the fan.
- You will find the M3H rating of a fan on its packaging.
Step 2. Consider the noise produced by the fan
The next thing to consider is the sound rating of the fan, which is often measured in Sone.
- The new fans have values ranging from 0.5 (very quiet) to 6 (very loud) sone.
- Some people prefer very quiet fans, while others appreciate the privacy offered by the loudest fans, especially in public areas of the house.
- The sone rating of the new fans will also be printed on the box.
Step 3. Choose the location of the fan
The location of the bathroom fan is important. You should install it in the middle point between the shower and the toilet for optimal ventilation. However, if the bathroom is very large, you may need to install more than one fan.
- If you are installing a new fan, you will need to consider the arrangement of the ceiling, where the main body of the fan will be located. You should place it in the space between two joists, in an area free from pipes or other obstructions.
- If you are replacing an old fan, the simplest thing to do is to put the new model in the seat of the previous one (if you have no good reason not to).
Step 4. Get the tools you need
Installing or replacing a bathroom fan are pretty straightforward DIY projects for people with basic woodworking and electrical engineering skills. Before starting, it's a good idea to get all the necessary tools and materials.
- You will need simple tools, such as a screwdriver and pliers, as well as a drill and a saw.
- As materials, you will need hose, a vent cover, screws, putty, and protective caps. If you are going to run the pipe through the roof, you will also need shingles and concrete and nails for siding.
- You will also need a ladder to reach the fan from below, safety glasses and a mask to wear when using the drill and a harness for roof work.
Method 2 of 3: Installation
Step 1. Drill a reference hole and mark the ceiling
Take the drill and use an extra-long, 2cm blade bit to drill a reference hole in the ceiling where you want to place the fan. Measure the fan box.
- Go up to the attic, find the reference hole and remove the surrounding insulation. Use the measurements you took to make sure the fan fits between the two joists.
- Go back to the bathroom and measure the vent on the fan. You will need to use these measurements to drill a properly sized hole in the ceiling.
- Use a pencil and ruler to draw the area dedicated to the air intake, using the measurements you have just taken.
Step 2. Cut the hole for the air intake
Use the saw to remove the portion of the ceiling you just marked. If you don't have a traditional saw, you can use a rotary cutting tool, such as a rotozip type, or drywall saw.
- Do not drop the ceiling section to the ground after cutting, as it may carry away other pieces of wall or plaster.
- Use your free hand to support the ceiling piece and gently lower it to the ground.
- Remember to wear safety goggles and a face mask when sawing plaster and wall to protect your eyes and lungs.
Step 3. Put the fan in place
Before lowering the fan into the hole you just drilled, attach an elbow tube to the fan outlet port using aluminum tape.
- Insert a connector into the side hole of the fan, then slide the metal support brackets into place.
- Center the fan over the hole in the ceiling and lower it into place, making sure the connection points are oriented correctly.
Step 4. Secure the fan to the joists
With the fan positioned correctly, unfold the metal brackets until they reach the joists on both sides of the box. Use drywall screws to secure each bracket securely to the joists.
- With the fan fastened, take the hose and attach one end to the elbow tube that comes out of the fan box, using aluminum tape.
- Now is a good time to run new or existing electrical wiring through the connector on the fan box. You can secure the cables by tightening the connector screws. Note that you will need to use a three-wire cable if the fan also has a light.
Step 5. Find a suitable exit point for the pipe
The next step is to find the straightest and shortest path from the fan to the outside. The longer the pipe, the less efficient the fan will be.
- It is essential that the fan exhausts the air to the outside. Blowing it directly into the attic would encourage mold growth and could cause the beams to become moldy.
- You can run the ventilation duct into the side wall or roof, whichever is most convenient. Just make sure it's as straight as possible and isn't too tight.
Step 6. Attach the duct cover
To do this you will need to follow a different procedure if the exit is on the roof or side wall.
- If the exit point is on a side wall, choose a point between two uprights and take reference measurements inside, so that you can find the same point outside. Use a 10cm hole saw to drill through the wall from the outside, then secure the lid.
- If the exit point is on the roof, draw an appropriately sized circle inside and use a reciprocating saw to cut it. Then go up to the roof (taking all necessary precautions) and remove the tiles covering the hole you just drilled. Install the duct cover, using concrete and siding nails, then put the shingles back in place.
- Go back to the attic and attach the end of the pipe to the conduit cover connector using aluminum tape.
Step 7. Complete the connections to the fan box
Depending on the type of fan, you may need to connect cables from the attic or bathroom. Be sure to read the manufacturer's instructions and double check that the power is off before proceeding.
- Open the fan box and pull the cables out of the electrical unit. Find out 2 cm of the fan cable and electrical cable you inserted earlier.
- Roll the cables of the same colors together (usually white with white and red or black with black) and add the connectors. Wrap the bare copper wire around the green insulating clip or screw and tighten to secure.
- Put the cables back into the electrical unit and replace the box cover.
- If you do not feel able to complete the electrical connection yourself, do not hesitate to call a professional electrician to install the fan or to inspect your work once it is finished.
- Also consider that aluminum cables (unlike copper cables) require special precautions and any electrical work involving this type of cable should be done by a professional.
Step 8. Attach the grid
You're almost done. Connect the motor to the electrical unit and secure it with the screws provided.
- Install the decorative plastic grille by sliding its mounting cables into the appropriate slots. Make sure it fits snugly against the ceiling - spread the cables slightly apart to create more tension if needed.
- Reconnect the power and test the new fan to see if it works.
Method 3 of 3: = Replacement
Step 1. Disconnect the power
You will need to remove power from the fan from the electrical panel.
Step 2. Disconnect the motor and electrical wires
Put on a pair of gloves, goggles, and a face mask, then remove the grille covering the old fan. You may be surprised at the amount of dust and debris that will fall!
- Unscrew or disconnect the motor unit from the fan box, then open the electrical unit and carefully pull the wires out.
- Remove the connectors and unwind the cables to disconnect them. It is a good idea to double check that the cables are not powered before this step.
- Open the cable tie to free the electrical cable from the fan box.
Step 3. Go to the attic and remove the box
Disconnect the hose from the fan box and the duct cover.
- Remove the electrical wires from the fan box.
- Use a drill to remove the screws holding the old fan brackets to the joists, then remove it from the ceiling.
Step 4. Install the new fan
Go back to the bathroom and unpack the new fan. If it is the same size as the old one, you can install it immediately.
- If the new fan is larger than the old one, you will need to widen the hole in the ceiling. You can do this by tracing the perimeter of the new fan, then cutting it out with a drywall saw.
- If the new fan is smaller than the old one, you can grout around its box to fill the free spaces after installation.
- Go to the attic and drop the new fan into the hole. Make sure the unit is oriented correctly.
- Slide out the extendable mounting brackets and secure them to the joists with a drill and screws. You may need to ask someone to hold the fan from underneath during this operation.
Step 5. Attach the tube
Once the fan is mounted, attach an elbow tube to the fan outlet port using sheet metal screws. Then attach a new tube to the elbow tube.
- You can use the pipe from the old fan if its diameter allows.
- Keep in mind that if you are going to use an older and smaller tube the fan will not work at maximum efficiency.
Step 6. Connect the electrical cables
Insert the electrical wire into the connectors of the new fan and secure it with a cable tie.
- Open the electrical unit (from the ceiling or bathroom, depending on the model) and pull out the fan cables.
- Connect the electrical wires to the fan wires by rolling the wires of the same color together (white with white and white or red with black) and using a connector.
- Wrap the bare copper wire under the insulation clip, or screw and tighten to secure. Put all cables back into the electrical unit and replace the cover.
Step 7. Complete the work on the outside
If you have replaced the old air duct with a new hose, you will also need to install a larger cover on the roof or side wall.
- Take all necessary precautions to work on the roof. Remove the old lid and use a saw to enlarge the opening as needed.
- Pull the end of the duct through the hole, 2 cm past the edge of the roof or wall. Secure it with sheet metal screws and seal with putty.
- Attach the new lid to the end of the duct. If it's on the roof, replace the unstable shingles.
Step 8. Attach the grid
Go back to the bathroom and install the motor unit by inserting it into the box and screwing it in. Attach the decorative plastic grille, then turn the power back on to verify that the new fan is working.
Advice
- Get a fan that moves enough air for the size of the bathroom to be aerated.
- If you're not comfortable with electrical work, drywall, or exhaust ducts, hire someone to do it for you. You end up saving time and frustration and the expense is justified.
- Get the quietest fan you can afford, you'll be happy in the end.
- Use a ladder for high ceilings.
- Buy the bathroom fan from a reputable dealer.
Warnings
- If you use power tools for any part of this project, make sure you are familiar with their operation and follow the recommended safety procedures.
- If you don't know anything about electricity, it's best to hire a professional. Connecting the wrong wire can cause a lot of damage and the possibility of shorting or being electrocuted.
- If you are using a ladder, get someone to help you hold it while you install the fan.
- Cut off the power supply before installing the appliance.
- Make sure you follow all instructions completely.
