Tilting an array of solar panels will affect how much power you get across the year, however the ideal angle for solar panels is not as clear cut as you may think, and there is a lot of misinformation on the internet that we’d like to clear up.
Firstly, if you have a tile roof solar panels must be installed at the same angle as the roof. Typically in Australia, this is 22.5 degrees. Solaray installs brackets that attach to the frame of your roof. We then fix two rails per row of panels, and the solar panels are mounted onto these rails. There is a small clearance under the panels but there is no way for us to tilt the panels.
What is the ideal tilt for solar panels?
If you have a tin roof (colorbond, kliplok etc.) we are able to install panels on tilt frames.
The angle of the sun changes from summer to winter. In summer a solar system in Sydney will output the most power across the day when solar panels are installed close to flat on the roof. In winter, the ideal angle is over 25 degrees, and so by tilting a solar array, all we are really doing is pushing output from one time of the year to another with very little impact on total yearly output.
This means that to maximise the benefit of your solar system the angle of your panels should be matched to your lifestyle, or more specifically to what time of year you use the most power. Many households use more power during summer due to air conditioning, pool pumps and the fact that it is a popular time to take time off work (and of course kids are on school holidays). Because of this, it often makes good sense to install panels flat on the roof to increase solar output in summer at the expense of loosing some output in winter.
Alternatively, a lot of households use more power in winter compared to summer due to heating. Up until now heating has been difficult to run off solar power because heaters are typically used outside the peak generating hours of the solar system. But with battery storage, the solar power that is generated during the day could be stored and then used in the evening. In this case, it may make more sense to tilt the panels to increase output in winter.
Installing solar panels on a flat roof
In reality, no roof is ever ‘flat’. A roof is designed for water to run off it and so it is commonly at around a 2 degree tilt. Furthermore, we are able to tilt solar panels around 3 degrees or so without using a tilt kit. This means that we will typically have solar panels on around a 5 degree tilt when we are installing them ‘flat’. This is an important point because a small tilt allows the panels to be washed clean when it rains, and ensures that water doesn’t pool on the panels.
The risk of installing solar panels with tilt frames
If you want to increase output in winter, the maximum tilt we recommend is around 15 degrees. Once we go over 15 degrees the risk of damage in a high wind event significantly increases.
Strong winds create a vortex over the solar panels that creates a strong upwards force on the array. The solar mounting kit is designed to handle this force, but this force can be transferred to your roof, which can cause serious damage because roofs are generally not designed to take a strong upwards force. It doesn’t make sense to expose yourself to the risk of expensive damage to your home in trying to push a little more output from summer to winter.
Furthermore, in Sydney, we often get strong winds coming from the south. This is a real problem for solar panels that are tilted back to the north. If your roof is exposed to southerly winds it is advisable to install your panels either flat on the roof or at a very shallow tilt.
The Cost of Tilt Frames for a Solar System
If you decide to tilt your panels, a ballpark cost for tilt frames is around $25 per panel. This means for a 3kW system with 12 panels you are looking at an additional $300 as an estimated round number. The key question to ask yourself when deciding on tilt frames is: ‘is this cost worth it?’ Are you prepared to spend $300 on tilt kits to save an extra $20-$50 off your winter power bill?
For personalised advice please give the Solaray Team a call on 1300 221 586, or leave a comment below and we’d be happy to help.