- The most efficient solar panels in the world are capable of 40 to 50% efficiency. However these are beyond the budget of homeowners looking to achieve a healthy return on investment
- To achieve the best return on your investment you should opt for a solar panel that offers a balance between cost and efficiency
- To compare efficiencies and prices of pv panels offered by installers operating in your area, fill in the form at the top of the page
How efficient are solar panels?
Most domestic solar panels are around 10 to 20% efficient. More efficient solar panels are available, although these tend to be beyond the requirement and budget of most residential installs.
However, when deciding on what solar panels will be best for your circumstances, you will want to look at which solar panel will give the best return on investment rather than just simply the most efficient solar panel.
Higher efficiency solar panels tend to cost more, so a less efficient but cheaper solar panel is likely to deliver a higher return on your investment. Less efficient solar panels will need a larger space on your roof to produce the same amount of electricity as a more efficient panel. You might still want to consider a higher efficiency panel if you have a particularly small roof or your roof only has a small area out of permanent shading.
You can enter your postcode in the form at the top of this page to compare prices from installers operating in your area. These installers will be able to advise you further on the best solution for your particular requirements.
Which are the most efficient solar panels?
As we explained in the section above, you shouldn’t just choose the most powerful solar panel. However, to give you an idea of the most efficient solar panels offered by leading brands, we have compiled the table below:
|Brand||Product name||Module efficiency||Type of panel||Maximum power (Pmax)|
|Suntech||STP320S - 24/Vem||16.7%||Monocrystalline silicon||325W|
|Trina||TSM-280 DC05A.08||17.7%||Monocrystalline silicon||290W|
|First||FS-4105-2 FS-4105A-2||16.2%||Thin Film||105.0W|
|REC Product List||REC 280TP||17.0%||Multi crystalline||280W|
The table below shows the efficiency of popular, but less efficient solar panels which, provided you have suitable roof space, often deliver a higher return on investment than the most efficient solar panels on the market:
|Manufacturer||Product name||Module efficiency||Type of panel||Maximum power (Pmax)|
|Suntech||STP255 - 20/Wem||15.7%||Polycrystalline silicon||255 W|
|Trina Solar||TSM-205 DC/DA80.08||16.0%||Monocrystalline silicon||205W|
|Canadian Solar||CS6X- 315P-FG||16.14%||Polycrystalline||315W|
|Yingli Solar||YL215C-24b||16.3%||Monocrystalline silicon||215W|
|Yingli Solar||YL200P-23b||15.4%||Multicrystalline silicon||200 W|
What factors impact efficiency?
There are a number of factors to consider which can affect the efficiency of your solar panel system:
Direction and angle of your roof
Your roof will usually need to be South, East or West facing and angled between 10 and 60 degrees to work at its peak efficiency.
The less shade the better. Your solar panels will have a lower efficiency if they are in the shade for significant periods during the day.
Solar panel systems need to be installed a few inches above the roof in order to allow enough airflow to cool them down. But this is less important in the US climate, so it works to our advantage.
Time of year
Solar panels work well all year round but will produce more energy during summer months when the sun is out for longer.
Size of system
Typical residential solar panel systems range from 2kW to 4kW. The bigger the system the more power you will be able to produce.
Types of panels and their efficiencies
The two main panel types are monocrystalline and polycrystalline silicon. Monocrystalline costs more to make but efficiency is higher, typically 13-17%. So you can in theory get more power out per unit of surface area. This might be a consideration where roof space is limited and could mean buying fewer panels to meet your needs.
Polycrystalline units are cheaper to make, but have lower efficiency, usually 11-15%. A third system combines one of these two panel types with a thin-film PV system, again more expensive, but capable of efficiencies exceeding 17%.