Where on your roof you install your solar panels will depend on the setup of your roof and the power required by your fan. If you fan does not require much power, you may be able to install it anywhere on your roof if your roof receives a lot of direct sunlight. However, if you have a high-powered fan and a roof that receives direct sunlight for only part of the day, you will want to install the fan in the area that receives the most light – which is often to the southern-facing side of the roof.