A number of different types of PV panels exist. The most widely used type for domestic applications are monocrystalline and polycrystalline silicon panels. From a practical perspective, there is very little difference between the two panel types.
Polycrystalline panels consist of visible crystals in different shades of blue and slightly less efficient than monocrystalline panels (which are dark blue with no visible crystals). However, this efficiency difference only means that a polycrystalline array with a rated capacity of 1,000W (1kW) may be slightly larger (cover more area) than a 1 kW monocrystalline array. Under identical conditions, both panels will produce the same amount of electricity.
PV manufacturers are developing panels from many other materials, with ‘thin film’ technologies offering the chance to produce power from a smaller amount of material – so reducing financial and environmental costs.
If you’re considering installing a PV system, it’s worth speaking to a few installers to see what’s currently on the market. You’ll need to weigh up factors including cost, efficiency and lifetime. PV panels are expected to last a very long time (30 years or longer), but their power output decreases over time. With cheaper panels, this decrease may be quicker. Good quality crystalline PV panels come with a guarantee that they will still give at least 80% of their maximum output after 25 years.