1. Locate the fan unit in your roof space Your system may have multiple fan units & therefore have multiple filters to replace. You can check your original system specifications on your invoice or get in touch to find out.

2. Power off the system Locate where the system is plugged in. Either turn the switch off or unplug the system. The system should be silent, indicating the fan has stopped spinning.

3. Cut the tape holding the filter in place & remove Use a craft knife to cut along the seam between the fan unit & the filter. Once the tape is cut, the filter should lift out easily.

4. Insert the new filter Check the airflow direction on the filter. The arrow should point down, into the fan unit. Filters are not perfect squares — if they don't fit in one orientation, rotate the filter 90 degrees.

5. Tape the new filter in place Apply good quality duct tape around the outside of the filter and fan unit to provide a good air seal.

6. Power the system back on Once powered on, you should hear the fan spin up again.