More and more people in Belgium are considering switching to solar panels. Not surprisingly, as the energy market is in full swing, prices continue to fluctuate and there is a growing awareness that we need to reduce our ecological footprint. But what is the yield of solar panels? In this comprehensive article, you will discover all about solar panel yield, with a special focus on the importance of thorough cleaning. We share practical tips, refer to external sources such as Flanders.be and Energy savings.be, and explain how you can optimise your returns.
"We think it is important to provide people not only with panels, but also with the right knowledge," says Hendrik, co-founder of Solarco.
Read on quickly to find out how you can benefit from higher efficiency and lower energy bills for a long time.
Why solar panels are a worthwhile investment in Belgium
Solar panels generate electricity by converting sunlight into energy. Despite our sometimes changeable climate, Belgium is certainly suitable for installing solar panels. On average, the annual yields in Belgium between 850 and 1,100 kWh per kWp. This means that a 4 kWp installation (about 10 to 12 panels) will generate between 3,400 and 4,400 kWh per year. With an average electricity price of €0.35 per kWh, this quickly results in annual savings of over €1,500.
Moreover, the system of premiums and subsidies in Flanders is still advantageous enough to reduce the payback period to 6-9 years on average (source: Energy savings.be).
"It may take a little investment, but after 6 to 9 years you often enjoy pure profit," said Sander, co-founder of Solarco.
How you can increase your returns, you will read later in this article.
Factors affecting the yield of solar panels
It is not true that every solar panel installation generates the same amount. Several factors affect the actual yield:
- Location and inclination: A south-facing roof with an inclination of about 35° performs best. East- or west-facing can still be cost-effective, but the yield will drop by 10% to 20% compared to an optimal south orientation.
- Type of panels: High-quality monocrystalline panels with an efficiency of 18-22% produce more kWh than older or cheaper variants.
- Inverter quality: The inverter converts the generated direct current into usable alternating current. An efficient device properly matched to the power output of the panels is crucial for high yields.
- Temperature: Solar panels perform less well if they get too hot. So ventilation and sufficient space under the panels are important.
- Cleaning and maintenance: Dirt, dust, leaf debris and bird droppings can corrode the panel surface, which has a direct impact on efficiency. We discuss this in more detail in the next chapter.
Why cleaning is so important for yield
One aspect that is often overlooked is keeping solar panels clean. Even a thin layer of dust can significantly reduce their ability to capture sunlight. According to some studies, the efficiency loss due to pollution can be as high as 5% to 10% on an annual basis (source: Test Purchase). Although rain and wind remove some of the dirt, stubborn dirt-such as bird droppings or moss-often remains.
Our experience at Solarco shows that solar panels that are cleaned regularly continue to perform better. Moreover, the lifespan of panels goes up if they are kept neat and clean. "After all, you also want to keep your car window clean for optimum visibility," jokes Hendrik, "so why not do the same for your solar panels?" For this reason, we offer a professional solar panel cleaning service using specialised brushes and osmosis water. This method is thorough, yet safe for the panels.
Average yield in figures
Based on our own data and external sources, we can give an estimate of the average yield per power in Belgium. Suppose you have a 4.8 kWp installation with about 14 panels. Then you can assume:
- Annual revenue: 4,000 - 5,000 kWh
- Annual savings: €1,400 - €1,750 (at €0.35 per kWh)
- Payback period: 6 to 8 years
These kinds of figures are obviously indications and can vary from situation to situation. External factors such as local legislation, prosumer rates and the (constantly evolving) energy tariff also play a part in your final return (source: Flanders.be). Sander stresses, "Good tailor-made advice is worth its weight in gold. What works for one home may work slightly less for another."
The role of maintenance and inspection
Besides cleaning, it is advisable to have the installation inspected annually or bi-annually. A solar panel inspection can reveal minor defects or inefficiencies, for example. Think of problems with the cabling, micro-inverters or loose connectors. These are often defects that you do not immediately notice yourself, but which can have an impact on power production. Early detection prevents greater damage or yield loss.
In addition, a periodic solar panel maintenance useful to check that everything is still working as it should. This allows us to submit any warranty claims to the manufacturer more quickly. "Bear in mind that with solar panels you are bringing into your home an installation that can last for decades," Hendrik explains. "A little love and attention is therefore more than rewarding."
How do you calculate your own yield?
Many manufacturers and suppliers offer online tools that allow you to estimate your expected yield. But beware: these tools often do not take into account factors such as shade, pollution and the exact roof construction. So it is wise to engage a specialist, such as Solarco, for a personal analysis. We not only look at your roof orientation and pitch, but also consider your future plans-think an electric car or heat pump.
Moreover, with us, you receive a fully customised simulation, including an estimate of the payback period and the expected return over 25 years. "We want people to get the full picture, not just the rosy side," states Sander. "An informed decision takes you long term."
Common misconceptions around yield and cleaning
A persistent misconception is that rainwater alone would be enough to rinse solar panels clean. While a heavy rain does indeed wash away dirt, a thin film usually remains on the panels. In prolonged drought periods, dust can also accumulate. Bird droppings and moss fringes cannot be easily washed away either. We therefore recommend professional cleaning at least once every one to two years. This ensures continued high efficiency.
Another misconception is that maintenance costs too much and thus negates the benefits of solar panels. In practice, the costs of cleaning and servicing are relatively low, especially compared to the extra yield you get from them. Moreover, you avoid bigger, expensive repairs in the long run. According to calculations by various experts (source: own professional experience and external studies) regular cleaning can increase yields by up to 5-10% compared to panels that are rarely or never cleaned.
Case studies: corporate and private
Suppose you are the owner of an SME with a flat roof structure and a hefty annual energy cost. By installing 50 solar panels (about 20 kWp), you can quickly generate towards 20,000 kWh of energy annually. At an electricity rate of €0.35 per kWh, this results in savings of €7,000 a year. In that respect, a cleaning and check-up every so often sounds like a relatively small investment.
Even as an individual, you will notice the difference. For example, do you have a standard family home and consume 4,000 kWh per year? In many cases, a 4 kWp installation will cover most of your consumption. This will leave you with more money for other things every month.
How do you get started with solar panels and what should you remember?
Before buying solar panels, it is wise to check the condition of your roof. A solid roof construction and good insulation will ensure that your panels remain stable and that you will not face any surprises later on. It is also smart to consider your own energy consumption and future plans, such as buying an electric car or a heat pump. The better you coordinate this, the more profitable your system will be.
A must is to look for a reliable installer who will work with you to create a tailor-made plan. At Solarco, we analyse the exact position of your roof and use advanced tools to calculate your expected yield. We focus on quality solar panels that last and offer excellent maintenance service to keep your installation in top condition at all times.
Conclusion: cleaning as key to high yields
Investing in solar panels remains a smart move for both individuals and businesses. With an average payback period of 6 to 9 years and a potential return of 8 to 12% per year, solar panels do better financially than many traditional forms of investment. However, it is important to maintain your installation properly, especially through cleaning and regular inspection. This is the only way to get the maximum yield from your panels and extend their lifespan.
Do you still have questions about solar panel yields, the best way to clean them or the options for your specific situation? If so, feel free to contact our experts. "We like to build a long-term relationship with our customers by giving honest advice and delivering quality work," says Hendrik. So don't hesitate to ask for advice or help if you want to delve into the fascinating world of solar energy.
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