From some of the adverts you see you would think there is only one sort of solar panels…. in fact there are several alternatives.
The type of panels generally available are:
- Monocrystalline solar panels The highest cost but the most efficient with a long history of use.
- Poly-crystalline Similar to mono-crystalline panels, but the silicon used has a different structure which is easier to make and therefore cheaper but less efficient in watts per m2.
- Thin-film This includes several technologies of which the latest is CIS. These panels are the usually the lowest cost panels but can be twice the area of a Monocrystalline panel for the same output.
- Hybrids There are also a number of hybrid panels around which combine different technologies to improve all round performance.
Don’t get too confused by the marketing hype and the quoted efficiencies.
Unless you are have limited space to put the panels the best panel is the one that produces power at the smallest price per watt and will continue to do it for the longest time.
An advantage of having larger, but lower efficiency, panels is that more of the roof is shaded by the panels in the summer. This will reduce the heat gain in the roof space, saving on cooling costs.
The only times that efficiency becomes important is when;
- You are running the whole house off panels and you need more area for low cost panels than you have got roof area – more for off grid applications.
- You only have a small North-facing roof.
- The roof is Badly Shaded.
As well as the cost per watt you should also looking for panels from reputable manufacturers that come with a long guarantee (Up to 25 years). Additionally you would be advised to ask for a 5 year installation guarantee.