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 manufacturers’ 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.
1. Are efficient Solar Panels best?
Solar PV Panels power is measured in kWp (kilo Watt peak) refering to performance under STC (Standard Test Conditions). Efficiency 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. This performance variable is affected by the quality of the silicon cells and the clarity of the glass.
Temperature co-efficient: Heat increases electrical resistance, which reduces power. Solar PV Panels with a lower “temperature co-efficient” maintain power at higher temperatures, generating more kWh under the same conditions.
Heat capacity: Solar PV Panels that can dissipate heat better 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 maintain power over the years, while poorer quality Solar Panels will degrade through breaks in connectors, diode failures, water ingress, thermal cycles and 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 efficiency is not everything, while efficiency does mean you can get more power per square meter, making more of your available space, it may not mean you generate more kWhs.
How do you know which 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 variables. Using historical local weather data alongside databases of over 400 Solar Panel manufacturers, hundreds of Inverter manufacturers 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 extremely accurate forecasting. For example, you can add coniferous or deciduous trees with further adjustable settings to accurately simulate the leaf density to ensure accurate shade forecasting. There’s also a calculation for the cooling effect of the wind on the panels…. they really do consider every variable.
Naked Solar have a team of highly trained Solar PV Designers who can produce quotes with PV Sol reports that allow you to make a fully informed choice about which system will best suit your needs.
2. 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, dormers 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 your investment in clean energy.
Take a look at the two examples above—it demonstrates why high wattage panels can be a red herring. For Panel 1 – Sunpower P7 550W, using “powerful” SunPower P7 550W panels limits the roof to just one row. Because the physical footprint of each panel is so large, there’s only enough room for 1 row of panels, leaving a huge amount of prime Solar real estate empty.
For Panel 2- Sunpower P7 440W, Switching to the compact P7 440W model, the dimensions suddenly work in your favour. Fitting two full rows in the same roof space increases power, meaning you’re generating significantly more energy for your home and getting a lot more bang for your buck.
Ultimately, there is no one-size-fits-all solution; while smaller panels solved the space issue here, a different roof layout might find that the higher-output 550W panels are the most effective path to maximising your energy yield.
Our expert design team provide free PV Sol reports, finding the perfect Solar PV solution for you.
3. 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 for our feathered friends. Interestingly, some find that mesh acts as a selective filter; while it keeps out the larger, more disruptive birds, smaller birds 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.
4. 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: These guarantee against any manufacturing defects, i.e. physical faults with the panels. Warranty timescales vary from 12-40 years. Warranties usually offer a replacement panel or refund the cost of a replacement panel with very few covering scaffold, fault investigation and labour, which are the most expensive parts of dealing with Solar panel faults.
Performance warranty: Sometimes called degradation warranty, this warranties how much power a Solar PV panel will retain after 25 to 30 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 panel’s datasheet for details.
All-Inclusive Warranty: Sunpower and Solarwatt are the only manufacturers offering full service warranties, 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 like Naked Solar as the manufacturers recongnise the need for correct installation to ensure Solar Panel durability.
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 12 years. If you have a ‘degradation’ issue in year 13, you may find the manufacturer blames the product, which is now out of warranty.
5. Are Solar Panels still ugly?
Solar panels have truly evolved beyond their original purely functional form. Gone are the days where arrays were defined by those glaringly obvious silver grid lines, white backsheets, and chunky silver aluminium frames that sat awkwardly against your roof tiles.
Those older designs were built for solar farms first, with curb appeal coming in as a very distant second. Thankfully, not only has Solar PV technology and performance advanced rapidly, so has solar 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 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 enhancing customers’ rooftops.
