Buying, Panels, Solar -

Solar panels - What to Look for when Buying Panels

The cells on Solar or Photovoltaic (PV) panels absorb the energy from sunlight. Circuits within the cells collect that energy and turn it into Direct Current (DC) electricity. The price of solar panels has come down dramatically over the last few years.

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The most important aspects to look for when buying solar panels are: 

    • Is the panel poly or mono–crystalline?
    • Power ratings
    • Efficiency
    • Quality
    • Durability
    • Manufacturer’s assurances

Poly or mono–crystalline

The most commonly available panels today are either poly-crystalline or mono-crystalline solar panels. They basically do the same thing, the main difference is the type of silicon solar cell they use; mono-crystalline solar panels have solar cells made from a single crystal of silicon, while poly-crystalline solar panels have solar cells made from many silicon fragments melted together. Mono-crystalline panels, in general, have higher efficiencies and sleeker aesthetics than poly-crystalline panels but are more expensive. Poly-crystalline panels can be recognised by their blueish colour. The option you choose comes down to your personal preferences, space constraints (polycrystalline cells will take up more space for the same power rating), and finances.

Power ratings

All solar panels receive a power rating indicating the amount of power they produce under standard test conditions, which can be used to compare different panels. Most solar panels on the market have power ratings in the range of 150 to 420-Watt peak (Wp). A higher power rating means that the panels are more effective at producing power. These ratings are outputs under ideal conditions, and you will probably find that the panels don’t produce these ratings under normal conditions. A general rule of thumb is to install a solar energy system with as much power output as you can afford (or that your roof can accommodate).


Solar panel efficiency represents how effectively a solar panel can convert solar radiation into electricity. The most efficient solar panels commercially available today have a solar panel efficiency of just under 23%. Efficiency is particularly important if you have limited roof space and large energy bills.

Quality and durability

The International Organization for Standardization (ISO) has created quality assurance standards for the manufacturing industry known as the ISO 9000 series. Solar panel manufacturers can be certified ISO 9000-compliant to indicate that they meet those standards. Solar panel durability metrics measure how well panels will hold up over time in real-world conditions. The International Electrotechnical Commission’s (IEC’s) 61215 reliability standard evaluates panels by performing stress tests simulating the decades of outdoor wear and tear that solar panels encounter during their lifetime. These tests are designed to identify potential premature failure problems with solar panels, and panels that meet the standard are more likely to survive in the field.

Manufacturer assurances

Manufacturers’ warranties are an important complement as they indicate both technical specifications and business practices. In the unlikely event that a problem occurs post-installation, a strong warranty ensures that your service and support needs will be covered. Output warranties can be up to 25 years, generally meaning that the panel will still produce at least at 80% after 25 years. Material warranties can be up to 10 to 12 years, giving the guarantee that the materials will not fail within this timeframe.

Have a look at SunStore's Solar PV panels and see what we offer!


Read more:

SunStore Solar System Sizing Calculator
9 Easy Steps towards installing Solar
Solar panels - What to Look for when Buying Panels 
Wiring solar panels: Series or parallel?
What DC Wire Sizes to use for your Solar PV System?
What size of inverter do I need?
What are the elements of a Solar PV system?
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(source: adapted from