Best types of solar panels for domestic properties

Solar panels come in all sorts of shapes and sizes. Some are used to produce grid-level energy production, some are installed on domestic rooves and some exist to stop your calculator from running out of battery.

What are the main types of panels?

There are essentially two primary types of solar panel: monocrystalline and polycrystalline.

Both types are made via essentially the same process, except that the mono silicon used in monocrystalline panels requires an additional stage of processing, creating a higher purity finished product.

Whereas polycrystalline is created from lots of small crystals, monocrystalline uses one large crystal. This means monocrystalline panels are more efficient.

Due to technological improvements and the general decrease in the cost of solar panels, monocrystalline panels have now become the dominant form of solar technology with polycrystalline effectively becoming obsolete.

Advanced panel designs

Half-cut solar cells

Half cut panels take the standard monocrystalline design and cut the panel into two parts. This technique allows two separate paths for electrons to flow, reducing the impact of shading or damage. Half-cut panels can maintain up to 50% more efficiency when experiencing partial shading compared to standard panels.

Most half-cut panels also make use of PERC cell technology helping to further increase efficiency.

PERC cells (Passive Emitter Rear Contact)

PERC cells use an additional layer that reflects unused light back into the cell. These panels produce 6-12% higher output efficiency compared to traditional mono cells. They also cope better in lower light or shaded conditions.

Heterojunction Technology (HJT)

This cell design combines crystalline silicon cells with a thin film layer of amorphous silicon.

Benefits include:

• Higher efficiency
• Better temperature coefficient (better performance in heat)
• Improved aesthetics - unbroken black finish instead of white crisscross lines

A brand example would be the REC Alpha Pure panels.

N-Type TopCon solar cells

N-type solar panels are similar to PERC cells, but where P-type uses boron, N-type uses phosphorus. This makes them:

• More resistant to degradation
• Able to produce higher efficiencies
• Better performing in low light
• Bifacial - generating electricity from both sides

To find this technology, look at the Q Cells Q.Tron solar panels. Great for ground-mounted installations where they can use reflected light on both sides.

What makes a good solar panel?

Efficiency

When talking about solar efficiency this refers to the amount of electricity produced in proportion to the volume of sunlight that directly hits the solar panel. Even the most efficient panels lose some energy through heat, reflection, or sunlight passing through.

Degradation rate

Solar panels don't operate at 100% efficiency forever. A standard degradation rate is around 0.5% per year. Premium solar panels tend to degrade at around 0.25% per year - meaning over its lifetime, a premium panel will maintain its efficiency far longer.

Temperature coefficient

Most solar panels operate best at around 25°C (77°F) and will lose a small percentage of their performance if this is exceeded. Important if you're in regions with high temperatures.

Warranty

At the top end of the market, you can find 30-year performance guarantees. However, be careful - several solar manufacturers have experienced financial issues recently. A warranty is only as good as the company that offers it.

Picking your panels

Solar technology is developing quickly with new designs and innovations making it difficult to keep up with what's available on the market.

When choosing what type of solar panel is best for you, talk to your installer and work out the exact requirements for your property. Are you looking for rooftop or ground-mounted? What is the shading like? Is your roof south-facing?

Having an idea of what is available on the market and what questions you need to ask will allow you to ensure you find the best fit for you.