Homeowner Blog

What Solar Panel is Best for You?

David Woon 27 Aug 2020

We are often asked ‘what is the best solar PV panel for me?’. Unfortunately, it is hard to give one definitive answer to this question as each customer has different views on what the most important factors are and their motivation for investing in solar PV can have a significant impact on our response. 

Besides the environmental benefits of investing in solar, the two main drivers are grid independence and annual economic benefits or expected system payback. There are a couple of other considerations to take into account when deciding on the ‘best’ panel for your property, which include available roof space, aesthetics and longevity of the system. In this blog we’ll touch on all these points and hopefully provide you with a more informed idea of which panel is best suited to your needs.

Available roof space

All solar PV panels have roughly the same dimensions (1700mm x 1000mm) regardless of their power rating or efficiency, so the amount of suitable available roof space often governs what the best solution is for your property. Due to the number of fixed costs in any installation, increasing the number of panels doesn’t always have a large relative impact on the total cost.

If you’re lucky enough to have a property with a large roof space, it is often advisable to opt for a more cost effective option using a standard efficiency panel to provide a large total installed capacity without a huge initial investment. If the amount of roof space is quite restricted, however, we would recommend installing a higher efficiency premium panel as they can generate around 30% more energy from the same roof space, meaning you can still have a large total installed capacity from a small roof space. 

Unfortunately, some roof spaces do sometimes fall on the small side for a viable solar PV system and we typically recommend a minimum system size of 10 panels, even with high efficiency panels, for a cost effective installation.

Aesthetics

The visual appearance of solar panels is something which can divide people, but in recent years solar panel manufacturers have made strides to improve the aesthetic appeal of an installation. There are a number of ‘all-black’ solar panels currently available which do prove popular due to their sleeker appearance. However, there is a price to pay for the improved aesthetic and if you aren’t concerned by the silver busbars (lines) on the panels then opting for a black frame with a white backing sheet rather than an all-black panel can provide a reduction in the initial investment.

Another consideration with an all-black panel other than the cost is the marginal decrease in efficiency. Solar panels are more efficient at lower temperatures, so by having a black backing sheet the panel absorbs more heat, warming the panel and decreasing the efficiency by approximately 3%. It is also worth noting that the highest power panels on the market are not all-black, so often there is a need for a compromise between aesthetics, cost and efficiency.

Longevity of PV panels

One of the attractive aspects of investing in solar panels is that they are built to last upwards of 25 years and are very low maintenance. The premium solar panel brands do offer a 25 year defects warranty along with an impressive 25 year power output guarantee. ‘Standard’ efficiency panels will also come with a defects warranty usually of 10-12 years, but their cells degrade at a quicker rate so their 25 year power output guarantee is significantly lower than a premium panel’s.

Premium vs standard panels plot

The initial investment of installing a premium panel compared to a standard efficiency panel can be fairly significant and in the region of £1,000 - £4,000 depending on the size of the system, often equating to a longer payback period. A premium panel should, however, often be viewed as a longer term investment which performs well throughout the lifetime of the system and has the added benefit of peace of mind aided by the product warranty and performance guarantee.

The difference in savings over a 25 year period between a standard efficiency panel and a premium system can be substantial and are often comparable to the uplift in cost of the initial investment.

Number of panels

1st year generation (kWh)

Total savings over 25 years

Difference in savings over 25 years

Standard

Premium

Standard

Premium

8

2,440

3,070

£8,925

£10,152

£1,227

12

3,660

4,605

£13,387

£15,227

£1,840

16

4,881

6,140

£17,853

£20,303

£2,450

20

6,101

7,675

£22,315

£25,379

£3,064

24

7,321

9,210

£26,778

£30,455

£3,677

As shown there are a number of factors that affect what might be the best panel for you and it is ultimately a personal preference as to which factors you deem most important. If you would like any help to deciding what solar PV panel is best suited to your needs please give us a call on 0118 951 4490 or drop us an email to info@spiritenergy.co.uk.

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Assumptions for modelling above:

  • 40% on site usage of PV generation for standard panel.
  • 32% on site usage of PV generation for premium panel.
  • Assumed 984 kWh/kWp for both panels.
  • Export payment rate 5.5p/kWh.
  • 1st year electricity price 15p/kWh.
  • Grid electricity inflation rate of 6% per year.
  • 0.83% per year cell degradation rate for standard panel over 25 years.
  • 0.32% per year cell degradation rate for premium panel over 25 years.

Topics: Solar PV

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