5 Solar PV Panel questions you haven’t thought to ask (but should)
Solar PV Panels: they’re all the same, right? Er…let’s take a walk through the maze of things to consider. There’s a bit of unavoidable jargon here, so we promise we’ll lead you out the other side.
Choice is all well and good, but when there are so many Solar PV panels all claiming to be the best, and that’s before you even get to Battery Storage, Inverters and other add-ons, it can all be a bit much. No need to worry, though. Naked Solar interrogate manufacturer’s claims and uncover all the essential facts for you. Here’s some little tidbits to show you how vital good information is to your decision…
What to look out for
Many factors affect solar panel performance and durability. Below, we answer common questions and slay a few myths.
Are more efficient Solar Panels better?
Solar PV Panels are sized in kWp (kilo Watt peak) which refers to their performance under STC (Standard Test Conditions). Efficiency simply refers to the kWp/m² of area. However, you need kWh (kilo Watt hours = units of electrical energy) the more kWh your system generates the bigger the impact on your bills. Does higher efficiency always mean more kWh? Well there’s more to consider alongside efficiency.
Low light level performance: When the light level drops, better quality panels will maintain higher power when there’s less light. This performance variable is affected by the quality of the silicon cells and the clarity of the glass.
Temperature co-efficient: Everything electrical increases in resistance the hotter it gets. Increased resistance means reduced power. Solar PV Panels with a lower temperature co-efficient are affected less by increases in temperature so they’ll generate more kWh under the same conditions.
Heat capacity: If a Solar PV Panel can dissipate heat better it will operate cooler and generate more kWh. So even if a Solar Panel has a low temperature co-efficient, it may perform badly if it can’t dissipate heat effectively.
Degradation: Higher quality Solar Panels will maintain their power for longer while poorer quality Solar Panels will suffer from degradation through breaks in connectors, diode failures, water ingress, thermal cycles which expand and contract the panel daily plus the movement caused by wind loadings. So while a high quality panel may perform at a similar level to a lower quality panel on day one, a few years down the line you’ll start to notice a drop off in generation with budget panels.
So while efficiency does mean you can get more power per square meter, making more of your available space, it may not mean that you generate more kWh.
So how do you know how different Solar Panels will perform on your roof?
Thankfully there is an answer. PV Sol software from Valentin and PV Syst are professional Solar PV design tools which take in to account all these factors. Using historical local weather data alongside databases of over 400 Solar Panel manufacturer’s ranges, hundreds of Inverter manufacturer’s ranges and hundreds of Solar Storage systems, both pieces of software will be able to give you a clear long term forecast of how specific combinations of components will perform on your property.
They are very technical (and very expensive) pieces of software that allow very accurate forecasting. For example, you can add coniferous or deciduous trees with further adjustable settings to accurately simulate the leaf density to ensure accurate shading forecasting. There’s also a calculation for the cooling effect of the wind on the panels…. they really do consider every variable.
Which panel is best for my roof?
While it’s easy to get fixated on the “biggest” number on a datasheet, the ultimate goal is often to squeeze the maximum amount of energy out of your available space.
Solar panels are physical objects with fixed dimensions, and roofs vary in size with features like chimneys, doormers and velux windows that can limit space. By choosing a panel size that allows for a denser, more clever layout, we can often fit more power in the available space, ensuring you maximise generation of clean energy.
Take a look at the two examples above—it’s a classic case of why chasing a single high wattage number can be a bit of a red herring. In Example 1, using the “powerful” SunPower P7 550W panels actually limits the roof to just one row. Because the physical footprint of each panel is so large, they hit the boundaries of the roof before we can add a second tier, leaving a huge amount of prime real estate empty.
Now, look at Example 2. By switching to the more compact P7 440W model, the dimensions suddenly work in our favour. We can fit two full rows onto the exact same roof. Even though each individual panel has a lower peak output, the sheer strength in numbers means you’re generating significantly more total power for your home.
Ultimately, there is no one-size-fits-all; while smaller panels solved the space issue here, a different roof layout might find that the higher-output 550W panels are the most efficient path to maximising your energy yield.
Our expert design team can provide a obligation free PV Sol report to find the perfect panels for your roof.
Will bird mesh keep birds out?
The truth is, there isn’t a one-size-fits-all answer. For many homeowners, an array can sit for decades without a single bird ever taking an interest. These systems remain perfectly clear and maintenance-free simply by virtue of their location or local bird populations.
However, for others, the gap between the panel and the tile is an irresistible real estate opportunity. Interestingly, some find that mesh acts as a selective filter; while it keeps out the larger, more disruptive pigeons, smaller birds might still find their way in, seeking protection from those very same predators.
Naked’s Top Tip: Be wary of quotes where bird mesh is “thrown in for free.” If you live in an area where nesting isn’t an issue, you might be paying an invisible premium for a solution to a problem you don’t have.
A quality installer should assess your specific environment rather than using mesh as a default “freebie” to pad out a quote. It’s about fitting what’s right for your roof, not just adding hardware for the sake of it.
What does a solar warranty actually cover?
Solar panels come with two different warranties: performance and product. However. these vary in clarity and unscrupulous installers often miss-sell based on their misleading assurances.
Product warranty: This guarantees against any manufacturing defects, i.e. physical faults with the panels. Mostly 10-25 years long, these warranties usually offer a replacement panel or refund the cost of a replacement panel but don’t cover scaffold, installation or the investigation to find the fault in the first place, which can be the most expensive part of all.
Performance warranty: Sometimes called degradation warranties, these guarantee how much power a Solar PV panel will retain after 25 years. All warranties promise their panels will retain at least 80% of their power after 25 years. Some manufacturers offer better warranties that guarantee more than 90% of their power after 25 years. Check the panels datasheet for details.
All-Inclusive Warranty: Sunpower and Solarwatt are the only manufacturers offering bumper-to-bumperguarantee, covering the product, its power output, and—crucially—the full cost of service required to fix it (including scaffolding and labour). These panels can only be installed by certified installers, for which Naked Solar is accredited for.
Guaranteed for 25 years? Beware of ’25 year warranties’ as some Solar Sales people point to the 25 year degradation/performance warranty, while the product warranty may only be 10 years. If you have a ‘degradation’ issue in year 11, you may find the manufacturer blames the product, which is now out of warranty.
Other degradation: The remaining issues that cause degradation are much smaller but still contribute to the overall loss of power from panels. These are less prominent in better quality panels which have better quality components and sealants.
Are solar panels still ugly?
Solar panels have truly evolved beyond their original purely functional previous form. Gone are the dayswhere arrays were defined by those glaringly obvious silver grid lines, white backsheets, and chunky aluminium frames that sat awkwardly proud of your roof tiles.
Those older designs were built for utility first, with curb appeal coming in as a very distant second. Thankfully, not only has Solar technology and performance advanced rapidly, so has aesthetics.
Today, we’ve entered the era of the all-black, ultra-sleek module. Modern panels feature deep, matte finishes and sleek design, allowing them to blend seemlessly with your roofline.
Choosing solar is no longer a compromise on aesthetics; it’s an upgrade that enhances the curb appeal and adds tangible value to a modern, energy-independent home. We’ve put together a dedicated Solar Panel Aesthetics page to bust the myth of “ugly” panels and showcasing some of our Installations adorning customers rooftops.
