We love putting solar on roofs (and tipis and other things). And we only use the good stuff. That is, quality tried and tested award winning products. Our solar installation team are arguably the most experienced in the area, continually being acknowledged for their superior workmanship and customer service.
It’s important when selecting the best panels for your solar system to bear in mind a few crucial factors aside from the price tag; after all, your purchase decision is one you’ll be living with for a very long time. And we think its worth it.
The cost of a solar panel is determined in part by the size (in Watts), physical size, brand, quality of materials, durability / longevity (or warranty period) and any certifications the solar panel might have.
Its important to consider both how solar panels are manufactured and what materials are used. When it comes to solar panels there are three tiers of manufacturer quality. Denby Energy only supplies solar panels from the first two tiers.
Tier 1 includes the top 2% of solar PV manufacturers. These companies invest heavily in research and development, use advanced robotic processes and have been manufacturing solar panels for over 5 years. Tier 1 producers use the best grade of silicon to produce solar cells – the higher the silicon grade, the longer the solar cell will last, and the better it will perform.
Tier 2 includes companies which invest less in research and development, are reliant on both robotic and manual work on production lines and have often been in solar panel manufacture for 2 – 5 years. Generally, Tier 2 manufacturers produce good panels at good prices.
Tier 3 encompasses 90% of new solar PV manufacturers. These companies only assemble the panels and usually don’t manufacture their own cells. They do not invest in research and development. While often available at a cheaper price, these manufacturers use human production lines for manual soldering of solar cells.
This is the rated power range which a panel will either exceed or not meet. For example, a solar system you purchase may have a ‘nameplate’ wattage of 200 watts, but due to quality control issues, may in reality only be 195 watts. A positive tolerance rating means the module will not only generate 200 watts, but possibly more, under standard testing conditions.
4. Temperature co-efficient
The temperature co-efficient rating is important to determine what the impact heat has on a solar panel’s operation after installation. The lower the percentage per degree Celsius, the better. The price of a module with low temperature co-efficiency can be a little more, but in Australia’s hot conditions, a little extra cost is worth it.
5. Conversion efficiency
The efficiency of how a solar panel converts light into electrical energy will determine how much power your system generates. If two solar panels cost the same, but one has a higher conversion efficiency; then that module provides the better value for money – assuming the claimed efficiencies are correct.
6. PID resistance
PID stands for Potential Induced Degradation. Caused by stray currents and triggered by certain climate conditions, the phenomenon can cause substantial power loss. Good solar panels will display little or no PID.
7. LID resistance
LID stands for Light Induced Degradation, which is a process that occurs in the first few months after solar panels are installed. While this eventually stabilises after a period of time, it can reduce the amount of power the module produces. A good solar panel will have little or no LID.
8. Embodied energy
Another important aspect to look at is the embodied energy of the solar panel – that is how energy intensive the production of the panel was and how quickly it will have paid itself back by producing more energy. Consider this aspect an environmental cost.
9. Durability / Longevity / Warranty
The durability or longevity of a solar panel warranty is important for a number of reasons. Primarily, it can be an indicator of the manufacturer’s confidence in its products. Reputable solar panels will have a performance warranty of a period of 25 years. Solar systems should last at least that long, so you need to find an installer who's offering a warranty or guarantee for that length of time.
The solar panels we use at Denby Energy have 25-year performance warranties (typically warranting that the panel will still produce at least 80% of its claimed power rating after 25 years) plus a 10 to 12 year warranty for the product itself. An installer may also give warranties for the mounting frame, workmanship and so on. Denby Energy is an exception, with a 25-year warranty for both performance and product, and higher performance criteria in the warranty.
10. Size and Watts
The size of the solar panel in Watts will directly affect the cost, as solar panels are usually priced (and compared) in dollars per Watt. Watts are related to the output of each module, meaning a 100 Watt panel installed under ideal conditions will generate 100 watt-hours of electricity each hour and a 200 Watt panel will generate 200 watt-hours each hour. Therefore expect to pay up to double the price for the 200 Watt panel, compared to the purchase cost of a 100 Watt module.
The output of a panel also affects the physical size of the panel, meaning the 200 watt panel will be larger in size to the 100 Watt module. The type of solar cells used in its production also determines the size of the solar panel. They key issue to consider is that your system sizing is enough to power your appliances, and that the solar panels will physically fit in the area you wish to install them.
Your northerly facing roof space (and increasingly, west) is very valuable solar power real estate, so you’ll need to consider carefully your future plans. If you believe at some stage you will wish to install more solar panels, you need to ensure you’ll have the space to do so, otherwise you may find you’ll need to replace existing modules well before the end of their serviceable life.
11. Types of solar cells used
There are 3 main types of solar cells and the best type for you will vary depending on the installation application:
Monocrystalline silicon offers high efficiency and good heat tolerance characteristics in a small footprint.
Polycrystalline (or multi-crystalline) silicon cell based solar panels are now the most popular choice in residential installs. Recent improvements in polycrystalline panel technology have resulted in the development of modules equal to or better than many monocrystalline brands in terms of size, efficiency and heat tolerance. Denby Energy regularly uses polycrystalline panels as they are more efficient in the northern NSW area.
Amorphous (or thin-film) silicon uses the least amount of silicon. While some thin film panels are among the least efficient solar cells, solar frontier CIS solar panels offer the highest conversion efficiency of any mass-produced thin-film module.
Questions? Please contact us on 0432 767 764 for free advice on the best solar systems for your unique needs.