Toilet Ventilation
The first toilet ventilation system I installed was in a house I owned in the North of Norway 20 years ago. It was an internal wall cistern and because the cistern was basically air tight and the overflow feeds directly into the toilet bowl i was able to draw air out of the cistern (and therefore the bowl) with an exhaust fan. As the overflow pipe inside the cistern had quite a small diameter i needed to upgrade to a more powerful fan to get the desired air flow. The power supply to the fan was connected to the rooms light switch and therefore started when you entered the room. After the fan upgrade it worked perfectly and as far as I know is still in use today.
The second one was made by my father in his house in Australia, he made a total of 3 in the same house. These were made with the cistern behind the wall in a technical room/closet. To be able to use a smaller fan and not have to worry about the size of the overflow pipe the system was built as shown in the picture. There was some concern that this would affect the flush power but it did not. The S-trap was installed to stop the fan from drawing air from the cistern. This photo does not show the pipe that was later added from the top of the fan and out of the house.
There are kits online for this system now, but i have not tried them.
