Solar Panel Glass – Tempered Vs Plate

When shopping for a solar panel brand, the issues at the forefront of people's minds are typically topics such as efficiency and wattage. An often overlooked issue is glass – and the type of glass used on a solar panel really does matter.

When you buy a solar panel, it's a long term investment – it should serve you well for decades. While most manufacturers offer lengthy warranties, some up to 25 years, it's important to note the manufacturer needs to be around to honor it. There's still many fly-by-nighters in the solar panel industry, cutting prices by cutting corners on component quality.

While a warranty from a solid company is a great insurance policy, there's also the inconvenience of needing to make a warranty claim – pulling the panels down, taking them in – it's all very disruptive and stressful. It's best to have peace of mind from the outside and you can only have that if every part of the panel is of the highest possible quality.

The dangers of cheap solar panel glass

Cheap glass can cloud over time. Clouded glass greatly reduces solar panel efficiency. Broken glass, aside from being a general safety issue and even if the glass only cracks, can allow water to penetrate and create a fire hazard – water and electricity simply do not mix.

When selecting either a monocrystalline, polycrystalline or amorphous solar panel, be sure to check out the type of glass being used. Look for panels that utilize tempered glass – this should be clearly stated in the panel specifications.

What is tempered glass?

Tempered glass, also known as safety glass or toughened glass, is anything up to six times the strength of normal plate glass. It is created by thermal or chemical means. We've witnessed panels using tempered glass flip over onto rock strewn ground with some force without breaking .. This is something we obviously do not recommend trying out, but it goes to show how strong the material is. When tempered glass does break, it shatters into small pieces rather than creating long and razor sharp shards.

Flat plate glass in solar panels

This is most often found in cheaper brands of monocrystalline and polycrystalline panels made by small, relatively unknown companies; however it can also be found in well known brands in amorphous (thin film) solar panels that have a glass plate component.

Most amorphous panels can only use flat plate glass due to the way they are constructed. Amorphous panels are usually created by applying special silicon rich gas called silane at high temperatures directly to the back of a glass plate or to a steel plate. Some manufacturers get around the comparative weakness by using thick flat plate glass, but this is still not as strong as using white tempered glass.

When buying solar panels, do not forget that this is an important point to check on – as mentioned, it should be clearly stated on the product specifications as to the type of glass used as it's an important feature. If it does not, the chances are it's flat plate glass and should probably be avoided.