Solar Panel Comparison
When considering alternative energy sources for your home, comparing solar panels is crucial to getting the best equipment and price for your solar photovoltaic system. Several factors come into play when selecting solar panels, including efficiency, price, warranty, and degradation.
The experts at NimbleFins have prepared this detailed solar panel comparison guide for you so you can make an informed decision and choose panels that meets your specific needs and budget.
- Compare Solar Panel
- How to choose solar panels
- How to Compare Solar Panel Proposals
- How many solar panel quotes should you compare?
Compare Solar Panels
To compare solar panels, you'll need to get quotes and proposals from multiple installers. The solar panel market is not like car insurance; meaning there's nowhere to enter your details once and get multiple solar panel quotes all at once. Instead, you'll need to engage with multiple installers and then compare their proposals.
In our experience, the initial quote process takes between 15 and 30 minutes with each installer, as you need time to provide information about your electricity usage and your home, and the solar designer will plan your system in response to these questions as you talk. In many cases, you can complete the quote process entirely over the phone or video conference from the comfort of your home or office without needing to meet the installer in person (that comes later), although some installers will come out to your home for the initial quotation process.
It is important to use an MCS-certified installer. MCS is a standards organisation and using an MCS certified installer ensures that equipment meets good standards of performance and that installers are technically safe and competent. MCS-certified installers have undergone a rigorous vetting process to demonstrate that they adhere to MCS Standards and are members of a Consumer Code which means strengthened customer protection for you.
MCS recommends that you make a solar PV panel decision based on comparing three quotes to find a good value quote with an installer you feel you can trust. Before you sign any contract you should have received a performance assessment specific to your property.
So, where can you get these three solar panel quotes to compare? There are essentially a few different types of solar panel installers and a few ways to contact them:
- Energy Suppliers: Octopus, E.on and Scottish Power have internal teams that install solar panels. In our experience, energy companies may not be as desirable for solar PV installs because of a combination of factors like more cumbersome quote processes, less choice of equipment (e.g. for shade) and reduced geographic coverage. FYI most big energy suppliers that don't have their own solar install teams have partnered with specialists like Effective Home and Fusion8.
- Specialist solar PV installers: From small and local to large and national (e.g. Effective Home, GlowGreen, etc.), there is a host of companies in the UK that specialise in solar panel installation. Some of these only do solar, while others work with other 'greener' products like heat pumps, and you'll also find some traditional heating companies moving into the solar space (e.g. Heatable).
- Comparison Sites: Some comparison and news sites have relationships with one or more solar panel installers. On a site like this, you enter a few basic details, which are then sent to one or more installers who work in your area. You should then expect to hear from one or more of the installers, via phone, text or email. Using this method can save you a little time in connecting with installers, and can be especially useful if you're not sure where to begin or which installer to contact.
How to choose solar panels
Which solar panel brand is best? If you're wondering about the best solar panel manufacturers, we have some solar panel brand comparisons below to help you learn and decide which might be best for you. Here, we compare solar panel brands on efficiency, price, warranty and degradation. You can also read more in our article on the Best Solar Panels.
(If you're wondering about installers, check out our article on the best solar panel installers.)
Solar Panel Efficiency Comparison
Monocrystalline cells typically achieve efficiency in the range of 20% - 23%, as illustrated in the data below, since they're made of single silicon crystals (not multiple crystals, like polycrystalline cells).
Of the solar panels we analysed, SunPower (Maxeon 6 445W) and Aiko (B-Type Black Hole A MAH54Mb 450W) provide the best max efficiency, at 23% each.
Behind SunPower and Aiko, Longi, REC, Jinko and Perlight all have models that achieve over 22% max efficiency.
Of the 15 panels we analysed, JA Solar's JAM54S31 Mono Half-Cell MBB Short Frame was the lowest, at 20.2%. What does this mean—how important is efficiency?
Lower solar panel efficiency might be an issue if you have limited roof space, and you need to get the absolute most out of your panels. A panel with higher efficiency can generate more watts per square meter, so if the size of solar panel system may not be large enough to provide for your home's electricity needs, then efficiency might be a consideration for you. But since most monocrystalline panels have pretty comparable efficiency metrics, there may be more important factors to consider, like the installed cost per kilowatt, the expected electricity generation each year, and the warranty.
| Manufacturer | Model | Max Power Output | Max Efficiency |
|---|---|---|---|
| SunPower | Maxeon 6 AC | 445W | 23% |
| Aiko | N-Type Black Hole A MAH54Mb | 450W | 23% |
| Longi Solar | Hi-MO 6 LR5-54HTB-430M | 435W | 22.3% |
| REC | Alpha Pure-R | 430W | 22.30% |
| Jinko | Tiger Neo N-Type 54 | 445W | 22.27% |
| Perlight | NTA 430W N-Type Mono Black Module | 430W | 22.02% |
| JA Solar | JAM54D41 LB | 435W | 21.80% |
| Sharp | 425w NU-JC425B | 425W | 21.76% |
| Suntech | Ultra V | 560W | 21.70% |
| JA Solar | JAM78S30 Mono Half-Cell MBB | 605W | 21.60% |
| Suntech | Ultra V Mini 405Wp | 415W | 21.30% |
| Trina Solar | Vertex S 410w All Black Panel | 410W | 21.30% |
| Longi Solar | 525W Hi-Mo6 | 525W | 21.10% |
| Project Solar | UK Evo Super Max | 455W | 21.01% |
| JA Solar | JAM54S31 Mono Half-Cell MBB Short Frame | 395W | 20.20% |
Note about power and efficiency stats: Within a specific product line, manufacturers tend to offer a few different power options. A range of 'sizes', in effect. And within each product line, efficiency will typically vary depending on the power output—the panels with higher max power output (in Watts, or 'W') tend to have better efficiency. For example, the following is a snapshot from SunPower's Maxeon 6 datasheet, where you can see the power output options (420W to 445W) and the corresponding efficiency scores (21.7% to 23.0%). This is typical across the industry, and just another thing to be aware of when comparing solar panels.
Solar Panel Price Comparison
To make it easier to compare solar panel prices, we've researched prices of some of the more popular makes and models in the UK market. We found that JA Solar, Longi and Jinko are some of the manufacturers with the cheapest solar panels. Solar panels from these three companies can cost less than £100 per panel (excluding installation).
At the top end of the cost scale are companies like Sharp and SunPower, with costs appearing to be £300+ per panel. But sometimes you get what you pay for—note that SunPower has arguably the best warranties of the panels we analysed, as well as the best efficiency (discussed above) and lowest degradation (discussed in the next section).
Most of the other brands fall in the £100 to £200 per panel price range, uninstalled.
| Manufacturer | Model | Average price (excl installation) |
|---|---|---|
| JA Solar | JAM54S31 Mono Half-Cell MBB Short Frame | £75 |
| Longi Solar | Hi-MO 6 LR5-54HTB-430M | £83 |
| JA Solar | JAM54D41 LB | £91 |
| Jinko | Tiger Neo N-Type 54 | £94 |
| Aiko | N-Type Black Hole A MAH54Mb | £112 |
| Suntech | Ultra V Mini 405Wp | £160 |
| JA Solar | JAM78S30 Mono Half-Cell MBB | £161 |
| Perlight | NTA 430W N-Type Mono Black Module | £162 |
| REC | Alpha Pure-R | £168 |
| Trina Solar | Vertex S 410w All Black Panel | £169 |
| Suntech | Ultra V | £170 |
| Sharp | 425w NU-JC425B | £299 |
| SunPower | Maxeon 6 AC | £522 |
But the cost of an installed system reflects much more than just the panel costs. To learn more about solar panel costs for an entire system, e.g. by kWh or by number of panels, please see our cost of solar panels research.
Solar Panel Warranty Comparison
Solar panel pay back can take in 8-12 years, in many cases. (By 'paying back' we essentially mean that the money you've saved not paying the grid for electricity exceeds the installation cost of the panels.) But how long will the panels last after they've paid back —that is, how long after you've 'paid them back' will you get 'free electricity'?
Many experts we've spoken to say that the expected life of solar panels is a good 25-30 years, but some panels will last longer than others. A good way to get a handle on how panels compare in these terms is to compare their warranties. Because if a manufacturer gives a longer warranty, it's a good sign that they expect the panels to last the distance.
Of the panels we assessed, Project Solar gives the longest product warranty—a 'lifetime warranty' that they told us is actually 99 years. This covers the panel itself. However, unlike other manufacturers, Project Solar hasn't spelled out a performance warranty for its latest model, the Evolution Titan, in its data sheet. (More on the differences between product warranty and performance warranty below the table.)
A possibly stronger overall warranty is therefore provided by SunPower. Their Maxeon 6 model is guaranteed for up to 40 years—for both the panel and the performance. Note, to get the 40 year warranty, the PV modules must be registered with Maxeon within 6 months of the warranty start date, otherwise the warranty terms are each 25 years.
| Manufacturer | Model | Panel Warranty | Performance Warranty |
|---|---|---|---|
| Project Solar | UK Evo Super Max (Evolution Titan) | lifetime (99 years) | n/a |
| SunPower (Maxeon) | Maxeon 6 AC | 25 or 40 years | 25 or 40 years |
| Perlight | NTA 430W N-Type Mono Black Module | 30 years | 30 years |
| Jinko | Tiger Neo N-Type 54 | 25 years | 30 years |
| Sharp | 425w NU-JC425B | 25 years | 30 years |
| REC | Alpha Pure-R | 25 years | 25 years |
| Longi Solar | Hi-MO 6 LR5-54HTB-430M | 15 years | 25 years |
| Longi Solar | 525W Hi-Mo6 | 15 years | 25 years |
| Trina Solar | Vertex S 410w All Black Panel | 15 years | 25 years |
| Aiko | N-Type Black Hole A MAH54Mb | 15 years | 30 years |
| JA Solar | JAM54D41 LB | 12 years | 30 years |
| JA Solar | JAM54S31 Mono Half-Cell MBB Short Frame | 12 years | 25 years |
| JA Solar | JAM78S30 Mono Half-Cell MBB | 12 years | 25 years |
| Suntech | Ultra V Mini 405Wp | 12 years | 25 years |
| Suntech | Ultra V | 12 years | 25 years |
What is a product warranty?
A product warranty essentially guarantees the equipment, for example, from material workmanship or manufacture defects that materially impede the power generation. It might cover glass breakage if there is no external cause of breakage. But deterioration in the appearance of the products (e.g. scratches, stains, mechanical wear, rust, mold, deformation or discoloration) likely will not usually count as defects under a product warranty.
Manufacturers typically have the option to repair, replacement or provide a refund, at their discretion. As with all warranties, be sure to check the terms yourself.
Also, check to see if only the equipment is covered, or if the warranty also covers the service costs incurred while repairing or replacing faulty equipment—it should.
What is a performance warranty (aka power output warranty)?
Solar panels degrade over time, losing a bit of output each year. Typically the degradation is around 1-2% the first year, then anywhere from 0.25% to 0.55% each year thereafter.
The experts at NimbleFins have estimated how much peak performance should remain after 25 years for many popular solar panels, using data from their power output warranties. The panels with the best performance at 25 years include SunPower Maxeon 6 AC, Suntech Ultra V and Trina Vertex S, as you can see in the chart below. These panels should still produce 92% of their original max power after 25 years of use.
A solar panel's performance warranty (or power output warranty) guarantees a minimum peak power output, basically putting a floor on this degradation and ensuring you get a minimum level of performance over time. Manufacturers typically guarantee performance for between 25 and 40 years. To compare performance warranties, we standardised the data across the group by calculating the minimum peak power that is guaranteed at year 25. Here are the results, ranked from best to worst:
| Manufacturer | Model | Performance Guarantee | Minimum Peak Power, at 25 years |
|---|---|---|---|
| SunPower | Maxeon 6 AC | 2% first year, then 0.25% per year | 92.00% |
| Suntech | Ultra V Mini 405Wp | 2% first year, then 0.55% per year | 92.00% |
| Suntech | Ultra V | 2% first year, then 0.55% per year | 92.00% |
| Trina Solar | Vertex S 410w All Black Panel | 2% first year, then 0.55% per year | 92.00% |
| REC | Alpha Pure-R | 2% first year, then 0.25% per year | 92.00% |
| Aiko | N-Type Black Hole A MAH54Mb | 1% first year, then 0.35% per year | 90.60% |
| Jinko | Tiger Neo N-Type 54 | 1% first year, then 0.4% for 30 years | 89.40% |
| Perlight | NTA 430W N-Type Mono Black Module | 1% first year, then 0.4% for 30 years | 89.40% |
| Sharp | 425w NU-JC425B | 1% first year, 87.5% guaranteed in year 30 | 89.48% |
| JA Solar | JAM54D41 LB | 1% first year, then 0.4% for 25 years | 89.40% |
| Longi Solar | Hi-MO 6 LR5-54HTB-430M | 1.5% first year, then 0.4% per year | 88.90% |
| Longi Solar | 525W Hi-Mo6 | 1.5% first year, then 0.4% per year | 88.90% |
| JA Solar | JAM54S31 Mono Half-Cell MBB Short Frame | 2% first year, then 0.55% per year for 25 years | 84.80% |
| JA Solar | JAM78S30 Mono Half-Cell MBB | 2% first year, then 0.55% per year for 25 years | 84.80% |
According to our calculations, the panel with the best performance warranty is the SunPower Maxeon 6—yet again, SunPower comes out on top. These panels are guaranteed for performance for 40 years (as long as you register the panels properly) and should supply at least 92% of the original peak power 25 years after installation.
Suntech also rates well for the performance warranty, also guaranteeing 92% of peak power at 25 years. (Oddly, their panel warranty is only 12 years, however.)
In contrast, some of JA Solar's panels were the least attractive of the group, although they still guarantee 85% of original power after 25 years.
The information about degradation should be found on the datasheet for any PV module. It will look something like this, which we sourced from JA Solar JAM54D41:
Note: separately check the workmanship warranty of your installer, which will be separate from the product warranties offered by the equipment manufacturer.
How to Compare Solar Panel Proposals
Once you have three or so solar panel proposals to compare, how should you actually choose the best one for you? Here are some considerations:
- Install team: Who does the work—are teams in-house employees or do they outsource the work in your area? This may or may not matter to you, but it's worth considering.
- Equipment warranties: Panel warranties typically range from 12 years to 30 years; battery warranties are usually around 10 years (and the best solar panel batteries can last 10,000 cycles, equivalent to 27 years of 1 full cycle/day).
- Customer satisfaction: Check online reviews for the installer e.g. Trustpilot. You can also look for reviews of the panel/battery manufacturers but these may be harder to find.
- Equipment output and efficiency: Solar panels for residential use commonly range from 395W to 450W of output each, with maximum efficiency ranging from 20% - 23%. Home storage batteries can vary between 5.2kWh and 13.5kWh of storage space per battery (multiple batteries can often be stacked for larger storage capability) with efficiency figures between 80% and 95%. These factors will determine how much power your system can generate/store for home use.
- Expected solar generation: Combine the output and efficiency figures (above) with the number of panels to determine the expected annual solar output of the entire system. How do different proposals compare in this regard? Ultimately, we think this is one of the biggest factors to compare when deciding on a solar panel proposal.
- Price: Cost is clearly a big factor, but be sure to weigh the relative costs of different proposals against the expected solar generation in each proposal. You may find that the solar power expected by different systems varies more than you'd realise (whether due to different solar panels, shade optimisation where needed, etc.)
Top tip for comparing quotes: Check the 'shade factor' that a proposal assumes in their power generation modeling. We looked through the fine print of a few solar panel quotes we received, and noticed a pretty glaring discrepancy between two different proposals. One company set our shade factor at 0.91, implying our site is partially shaded—a shade factor lower than 1 effectively reduces the expected power output of the panels. We think for our situation that a shade factor of 0.91 is fair, as there's a chimney on the roof and a large tree nearby. But another company (knowing about the chimney and the tree), set the shade factor at 1, implying no shade on our roof. That proposal assumed full sun and consequently estimated higher-than-realistic solar generation each year as a result—making their proposal look a bit better than it should, in our opinion. Be sure to check your shade factor and don't be afraid to question an installer's assumption about this!
How many solar panel quotes should you compare?
In our opinion, we think that you should get around 3 solar panel quotes from different installers. The MSC also recommends getting three quotes.
You're not only comparing price to get a good deal—you're also comparing the solar panel brands, efficiency stats and warranties, plus the solar power of the proposed system (as in, how much electricity it is expected to generate each year). For example, one installer might have equipment that is better suited to a specific situation, such as specialist shade-optimised panels, optimisers and inverters to generate more electricity on a semi-shaded roof.
Why it's important to compare multiple quotes
In our experience, if you contact three different installers you'll get three very different solar panel quotes. Not only will the price vary, but so will what you get for that price.
In particular, you may be presented with quite different systems, in terms of the size and output of the system. These are critical components of any quote, to ensure you get the most for your money. Here's why quotes can vary from one installer to the next. You can also read more about this in our article on solar panel quotes.
Different software
Many large solar installers use software that draws on satellite imagery of homes across the UK (e.g. what you see in the satellite view of Google Maps). There are a few of these software systems in the market, and some installers use the same versions. For example, OpenSolar is a very popular digital design software for solar panel systems.
You might think that using the same software would result in quite similar quotes, but in our personal experience, competing companies using the same software can create very different systems.
Why? A few reasons.
The 'solar expert' who designs your system
The 'solar expert' designing your solar panel system uses the software to visually 'place' panels on your roof. When doing so, they need to leave gaps between panels and also gaps between panels and the ridges or edges of the roof, as well as obstacles like chimneys. This involves a bit of guesswork. In our experience of getting quotes, we found that different 'designers' come up with different panel layouts, and some seem confident of fitting more panels on a roof space than others. This may be particularly relevant to you if you have a roof with lots of elevations and ridges and obstacles (in contrast to one large, wide expanse of open, unobstructed roof space).
Some companies have access to more than one version of software—when we got quotes, one designer used two different systems to see if he was able to fit more panels in one system than another. It was the same roof, but the two different design systems produced different systems, even when in the hands of the same designer.
For example, here are four very different proposals for the same home. We asked each to maximise our energy production. Notice the different placements, as well as the varying number of panels—some proposals only included 5 panels while another included 12 panels! Only one of the installers would install on the flat roof.
An installer's unique rules and relationships
Also, companies will have distinct sets of installation rules that may impact the system they propose, for instance:
- Minimum panel requirements: Companies may have minimum systems requirements or even requirements per roof section (e.g. Octopus and Effective Home informed us they require a minimum of 3 panels per elevation/face, whereas Glow Green and Egg were happy to put only 2 panels on a face).
- Roof pitch: Most (large) companies will not install on flat roofs.
- Gaps: Installers will require a minimum gap between panels and the ridges, hips and gable ends of your roof, as well as between panels and obstacles like Velux windows, chimneys, vent pipes and flues.
The equipment may differ
Not all installers work with all manufacturers. And, in fact, the larger, national installers typically have chosen just a few solar panel and battery options. They may choose manufacturers to accommodate different technical requirements (e.g. SolarEdge for shade) or choose manufacturers to suit different budgets.
For example, Glow Green quoted us three 'tiers' of solar panel system from 'value' to 'ultra' that were hundreds of pounds different in cost:
- Value: JA Solar solar panels + Pylon battery (our quote: £8,700)
- Premium: Trina solar panels + GivEnergy battery (our quote: £9,600)
- Ultra: Perlight solar panels + PureStorage battery (our quote: £10,100)
From the consumer point of view, an installer working with a limited set of products has it's perks—large installers can negotiate good prices with manufacturers if they limit the product range on offer; additionally, their 'solar expert' salespeople and installation folks can become more efficient and specialised in their knowledge by working with a smaller set of products.
But on the other hand, a large installer may not offer equipment that's best suited for your project. For example, while we love a lot about Octopus Energy in general, they weren't suited to do a solar install on our home. Why? Two reasons. First, since our test roof isn't huge, we needed an install on two different roof faces to get enough power generation (one south facing and one west facing). But Octopus said our west facing roof was too small—they will only install a minimum of 4 panels per face, but since we can only fit 3 panels on our westerly roof space, they completely ruled out putting any panels on that section. In addition, they don't (yet) install equipment suited to shade. Since we have a neighbor's tree and a chimney to content with, Octopus recommended we try another installer that could install a system with DC optimizers/micro inverters on each panel to maximise the power generation.
Smaller installers we spoke with may be more open to trying to acquire and install niche manufacturer requests from you—but know that installing unusual equipment would be a learning experience for them and they may not be qualified to install some manufacturers.
All of these reasons (e.g. software used, the individual designer, a company's unique installation rules and manufacturer partnerships) will certainly impact the size and output of the proposed solar panel system for your home. So comparing multiple quote proposals is really important when it comes to solar panel systems. You may be an expert by the end of the process!
Methodology
There is a large range of solar panel manufacturers and products are ever changing, as new technologies development. In order to choose the panels to compare in this article, we considered what might be most useful to consumers. With that in mind, we gathered quotes from many of the large, national installers to find out what solar panels they install—because these are the solar panels that a consumer is arguably most likely be offered by an installer. We also included a few panels that stand out for various reasons, like max power, for comparison sake.
About the pricing section: costs are notoriously hard to pin down for solar panels. Installers tend to lump all of the costs together into one figure, without itemising the costs of the products individually. The costs in the table above reflect our online research as well as phone calls to various companies; they reflect the average of the three cheapest quotes we could find, where available. Costs are for purchase only, without installation or all of the other costs associated with a solar panel installation. Additionally, costs will vary when buying them through installers as they likely will have unique pricing pre-negotiated with the manufacturer. We excluded a few panels discussed elsewhere in this article for which we couldn't find reliable pricing information.