Homeowner's Guide to Window Mounted Ventilation Fans

Posted on 13th April 2023

Window mounted ventilation fans, also known as window exhaust fans, are ventilation systems installed on glass windows, or acrylic boards and then mounted onto windows.

These fans are practical and affordable solutions for improving air quality and preventing moisture-related issues in your home. This comprehensive guide will provide you with essential information about window-mounted ventilation fans, their benefits, and how to choose the right one for your needs.

Why install a window-mounted ventilation fan?

Window-mounted ventilation fans directly expel air from the inside of a room to the outside, making them a suitable choice for rooms that rely on natural ventilation through an open window. They are particularly useful for bathrooms, kitchens, and laundry rooms, where they can help:

  1. Reduce humidity levels, preventing mould growth and condensation on surfaces.
  2. Remove odours, smoke, and stale air, promoting a healthier and more comfortable indoor environment.
  3. Improve air circulation, ensuring a constant supply of fresh air.

How do window-mounted ventilation fans work?

Window-mounted ventilation fans are installed on the glass of a window or an acrylic board mounted onto the window frame. They extract air from the room and expel it directly outside the property. This process creates a lower air pressure inside the room, allowing fresh air from outside to flow in and replace the stale air.

Benefits of window mounted ventilation fans

Easy installation: Since they are installed on acrylic boards and then mounted to the window, there is no need for complex ductwork or false ceiling installation. This makes the installation process quick and cost-effective.

Energy-efficient: These fans consume less power compared to other ventilation systems, making them energy-efficient and cost-effective in the long run.

Versatile: Window mounted ventilation fans can be used in various spaces, such as bathrooms, kitchens, or laundry rooms, where proper ventilation is essential.

Low maintenance: With fewer moving parts and no ducts to clean, window-mounted fans require very little maintenance.

Aesthetically pleasing: These fans are available in various designs and sizes, making them a visually appealing addition to any room..

Choosing the right window-mounted ventilation fan

When selecting a window-mounted ventilation fan, consider the following factors:

Noise level

A well-built fan operates between 25 to 40 decibels, while poor-quality fans can be as loud as 50 to 60 decibels. Check the fan's specifications sheet for its noise level before purchasing.

Installation requirements

For HDB flats, you need HDB approval to install an exhaust fan mounted on your window glass. Alternatively, you can avoid seeking approval by installing the fan on an acrylic board mounted onto the window frame.

Air changes per hour

Ensure that the fan has a suitable air change rate for your room size. Bathrooms with showers typically require 6 to 10 air changes per hour.

Cost and installation

The cost of a window-mounted ventilation fan can vary depending on the model, size, and installation complexity. On average, you can expect to pay between $350 to $450 for a window-mounted ventilation fan. Additional costs may arise if modifications are needed to the window or if the acrylic board needs to be custom-made to fit the window size.

Installing a window-mounted ventilation fan typically involves the following steps:

  • Measuring the window and cutting the acrylic board to fit.
  • Installing the fan onto the acrylic board.
  • Mounting the acrylic board with the fan onto the window.
  • Connecting the fan to the power source.
  • Testing the fan to ensure proper functioning.

Installation and maintenance

  1. It's crucial to hire a registered builder or trained window installer working under an approved window contractor for the installation process.
  2. Ensure the original bathroom window frame remains unchanged during installation to avoid seeking HDB approval.
  3. Regular maintenance is essential to keep the fan operating at an optimal noise level and ensure proper airflow.


Window-mounted ventilation fans are an effective way to improve air quality and prevent moisture-related issues in your home. By considering factors such as noise level, installation requirements, and air changes per hour, you can select the right fan for your needs and enjoy a healthier, more comfortable living environment. If you have more questions or are interested in having a window mounted ventilation fan installed in your home, please feel free to contact us. Our team of experienced technicians is always ready to help.

Call us at 9070 6060 to speak with a representative or get more information about our window mounted ventilation fan installation services.

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