Before investing in a solar installation , good preparation is essential to avoid costly pitfalls. In this article, discover the 10 mistakes not to make when investing in solar energy , which can quickly impact your budget, the performance of your panels and the lifespan of your equipment. Thanks to the expertise of a solar energy professional , you will learn how to avoid these common mistakes and optimize the performance of your installation, while controlling your costs. Follow these practical tips to make a sustainable and profitable investment.
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The 10 mistakes to avoid with solar: what you absolutely need to know before taking the plunge
Installing solar panels may seem simple on paper, but in reality, it's a project that requires careful thought, preparation, and vigilance. Too many individuals dive headfirst without asking the right questions, and end up regretting it. Loss of performance, unforeseen additional costs, poor sizing... mistakes are common, but avoidable.
It is precisely to help you avoid these pitfalls that we have listed the 10 mistakes not to make when using solar energy . This list is the result of years of experience in the field and discussions with hundreds of households who have chosen self-consumption or energy resale.
Before even signing a quote or choosing your installer, it's essential to be aware of these mistakes. They can significantly impact your budget, significantly reduce the performance of your panels, and in some cases, completely cancel out the expected profitability of your project.
In this article, a solar energy expert shares concrete advice to avoid unpleasant surprises:
Wrong orientation of the panels
Production estimates too optimistic
Choosing unsuitable equipment
Forgetting administrative procedures
Negligence in maintenance
…and many more.
By mastering these pitfalls, you increase your chances of making a profitable, sustainable investment that is truly suited to your situation.
1. Not adjusting your consumption before investing
The most common, and often the most costly, mistake is to want to maintain your current electricity consumption pattern , thinking that a solar installation will automatically adapt to it. This is a false good idea which often leads to unnecessary and expensive oversizing of the system.
Our self-consumption expert emphasizes one fundamental point: reducing your consumption before any installation is the key to a truly profitable solar project. It's not about depriving yourself, but rather adopting simple and effective actions.
Identify energy-consuming appliances
Start by identifying the equipment that consumes the most energy: old electric heating, outdated refrigerator, energy-consuming washing machine, etc. These appliances can weigh heavily on your energy bill.
Modernize Outdated Equipment
high-efficiency models is an investment that quickly pays for itself. Opting for a Class A refrigerator, installing a pellet stove, or a thermodynamic water heater can significantly reduce your consumption.
Integrate eco-friendly actions into everyday life
Turning off lights when leaving a room, unplugging unnecessary standby devices, avoiding leaving chargers plugged in all the time... These simple, free actions become automatic reflexes that make a difference.
Result: by reducing your consumption upstream , you reduce the necessary size of the solar installation , you control your budget , and you optimize the return on investment .
2. Trying to resell your electricity at all costs
This is a misconception that is still widespread, but is becoming less and less profitable. Many people think that installing solar panels is primarily about selling electricity to EDF or a third-party supplier , when in reality, the real savings are in self-consumption .
A few years ago, resale benefited from advantageous fixed rates over long periods , which made the investment attractive. But today, with the spectacular rise in electricity prices and the changing market, this logic is outdated.
The self-consumption expert insists: the priority objective must be to consume as much of the energy produced by your panels yourself as possible . This requires a well-sized installation, and above all, an adaptation of your daily habits.
Shift the most energy-intensive uses
Start your household appliances (washing machine, dishwasher, dryer) during the day , when your panels produce the most. This is also the ideal time to recharge your equipment: electric bike, scooter, or car.
Use smart programmers
Many devices today allow easy programming. This helps you synchronize your consumption with your solar production , without having to think about it.
By consuming your own electricity directly, you reduce your dependence on the network , you significantly reduce your bill , and you make your installation profitable more quickly . Resale of the surplus remains possible, but it must remain a secondary strategy.
3. Absolutely wanting to be totally autonomous in electricity
The idea of producing all of your own electricity may seem ideal. No longer dependent on the grid, no longer receiving bills, living in complete autonomy... it's tempting. But in reality, aiming for complete autonomy is often a bad calculation , both financially and practically.
Unless you live in a truly isolated location with no other options, trying to produce everything yourself requires you to significantly oversize your system . And this is neither realistic nor cost-effective for the majority of households.
The expert shares a very telling example. To be completely self-sufficient, he would have had to install three to four times more solar panels and invest in at least three times more batteries . The result: a multiplied cost, more complex management, and a much greater ecological impact.
Because yes, more equipment also means more resources extracted, more materials to produce and recycle. And a good portion of this stored energy wouldn't even be used continuously, which makes it all the less justified.
The right strategy is to aim for partial and intelligent autonomy . The idea is to cover your essential needs : in his case, this includes water via the booster pump , the refrigerator, the internet box, the telephone and the computer. For everything else, such as cooking or very energy-intensive appliances, the network remains there as support. And this is not a failure, quite the contrary.
It's a balanced approach : you gain independence, you control your budget , you reduce your ecological footprint , while maintaining your comfort of life.
4. Choosing the wrong type of inverter can be expensive!
The inverter is like the brains of your solar system. It transforms the direct current your panels produce into alternating current that your appliances can use. It also manages the power between your panels, your batteries, and the electrical grid. Therefore, choosing the wrong type of inverter can be a real problem, especially if you lose power!
Here are the three main types of inverters:
Resale inverters: These send all the electricity they produce directly to the grid, so you can't consume it yourself. Today, this option is no longer very attractive, and should even be avoided.
Conventional (or string) inverters: These are the most common. They power your home, store the surplus in a battery if you have one, and send the excess back to the grid. The problem? In the event of a power outage (general blackout, tree falling on the lines, etc.), these inverters automatically pause to avoid any electrical risk. The result: even with batteries, your system no longer works when you need it most.
Hybrid inverters: These are the best of the best! These inverters can operate with the grid or completely autonomously. In the event of a power outage, they automatically switch to your panels or battery, usually within one to two seconds. In practice, some users report that they don't even notice the outages thanks to this type of inverter.
Of course, hybrid inverters are a little rarer, a little more technical to install, and a little more expensive. But frankly, they're worth it: they keep your power flowing even when the grid is down. If you don't know what type of inverter you have, chances are it's a classic model that will shut down in the event of a power outage. And the good news is, it's possible to replace your inverter later by selling the old one.
4. Don't make the mistake of choosing the wrong inverter for your solar installation
The inverter is like the conductor of your solar system. It transforms the direct current produced by your panels into alternating current, ready to power all your devices. It also manages the energy between your panels, your batteries, and the electrical grid. Suffice it to say that choosing the wrong type of inverter can ruin the full potential of your installation, especially when there's a power outage!
Here are the three types of inverters you may encounter:
Resale inverters:
These send all the electricity you produce directly to the grid, without you being able to consume it yourself. Today, this option is no longer profitable, and you'd better avoid it.Conventional (or string) inverters
These are the most common. They power your home, store the surplus in a battery if you have one, and resell the excess to the grid. Except that in the event of a grid outage (a general outage or an incident), these inverters automatically shut down. This is a safety measure to avoid electrocuting technicians working on the lines. The problem? Your solar installation also shuts down, even if you have batteries. You then find yourself without electricity, just when you need it most.Hybrid inverters:
This is the solution recommended by professionals. These inverters can work with the grid, but also in standalone mode. In the event of a power outage, they automatically switch—usually within one to two seconds—to power from your panels or battery. In practice, many people report not even noticing the outage thanks to this type of inverter.
Sure, hybrid inverters are a little rarer, a little more complex to install, and a little more expensive. But their ability to keep your home powered even when the grid is down makes them well worth the investment.
If you don't know which inverter your system uses, chances are it's a standard model. And the good news is: you can easily replace your inverter later by selling your old one.
5. Incorrectly sizing your solar installation, a common pitfall to avoid
Sizing your solar installation is a key step and often a source of frustration. Finding the right balance between what you consume and what your panels produce isn't easy, especially when you have to consider day/night or summer/winter variations. Even experts can make mistakes, and it can be costly!
Two main mistakes can quickly happen:
Undersizing : This means having a system that's too small for your needs. You're not producing enough electricity and you have to buy a lot of energy from the grid. To correct this, you often have to add panels, change the inverter, or add modular batteries, which increases the bill.
Oversizing : This is the mistake our expert made. Having a system that's too large for your consumption means producing far too much electricity, especially when the weather is nice. Yes, you can sell this surplus, but the profit generally doesn't cover the cost of the excess equipment. For example, our expert produces four times more electricity than he needs for six months a year. In short, he paid for equipment that he doesn't use to its full potential, which could have been avoided.
The real challenge is that accurately estimating your consumption and production isn't easy. You have to take into account many factors: panel placement and orientation, shadows, seasons, and day and night consumption patterns. That's why it's crucial to carefully consider your needs before you get started.
And remember: it often takes a year or two of experience with your setup to fine-tune these calculations and truly optimize your system.
6. Getting scammed by an installer, a risk not to be overlooked
The solar market has exploded in recent years, often aided by generous subsidies. Unfortunately, this growth has also attracted unscrupulous players. Getting ripped off by an installer is a common mistake and can be very costly. Our expert, despite coming from a family of DIY enthusiasts, preferred to call on professionals, particularly in Switzerland, where he observed genuine professionalism in the installations.
Scams can take many forms. For example, some installers offer installations that are far too large and expensive, far beyond what you actually need. Others choose locations that are easily accessible to them, rather than the best ones to maximize solar production. However, with current technologies, even partial sunlight can be profitable.
There are also excessive markups, with very high prices for materials and labor. And in some cases, used equipment is sold as new, which is obviously to be avoided.
The key to avoiding these pitfalls is personal training. Understanding the basics of how it works, estimating your needs, and knowing market prices allows you to communicate with installers on an equal footing and spot unfair offers.
Here are the expert's practical tips:
Educate yourself so you know what you want and what it should cost. Monitor the construction site, checking that the equipment installed matches what was agreed upon. For example, if you requested Fronius inverters, make sure that this is the brand installed. Finally, don't pay everything at once. Spread the payments out into several stages: the first when you order, another at the end of the work, and a final one after a month or two of use, to ensure that everything is working properly. This gives you real leverage in case of a problem.
7. Damaging the structure of your house, a risk not to be underestimated
Installing solar panels , often on the roof, involves work that, if done incorrectly, can jeopardize the waterproofing of your home. A small leak on the roof can cause major damage, such as moisture or mold in the insulation, which is often invisible until detected. Repairs can then become very expensive.
The expert advises, if possible, to install the panels on a garage or garden shed . These lower structures make installation and maintenance easier. In the event of a leak, the damage will be less severe than in the main house.
It is essential to use qualified and reliable installers. Even if you don't need to monitor them constantly, remaining vigilant during the work helps ensure that waterproofing regulations are respected. The expert also reports a compatibility problem with the electricity meter , which caused delays and additional costs with EDF .
8. Not choosing the right location for your solar panels, a hindrance to performance
The location of solar panels is crucial to maximize electricity production . A positioning error can seriously reduce the efficiency of your installation.
There are several factors to consider:
Orientation and inclination : you should choose a location that maximizes exposure to the sun throughout the day and throughout the seasons .
The sun's path changes: in summer it is higher, in winter it is lower. What doesn't bother a distant tree in summer can create a shadow in winter.
Shadows are the most critical point. Shadows from neighboring buildings, chimneys, antennas, and especially trees can drastically reduce production, even if a small part of a panel is shaded. The expert prunes his trees every year to avoid this.
Ethically, cutting down a tree to optimize a solar installation remains a personal dilemma. The expert believes it is justified for the production of clean energy , but understands that others refuse out of attachment to their tree. The final choice is up to each individual.
Be careful not to blindly trust an installer who chooses a location for convenience (more accessible, lower) rather than to optimize performance. A sunlight study is essential before making any decision.
9. Thinking that solar panels only go on roofs, a preconceived idea to overcome
Traditionally, solar panels are installed on roofs to save space and benefit from maximum sunlight without shadows. However, they can also be placed on the ground , an often overlooked option that offers real advantages.
Advantages of floor installation :
installation costs , as there is no need to work at height, which reduces safety and specific equipment requirements.
Easier maintenance : easier access for cleaning and regular checks.
The possibility of DIY installation if you are a bit of a handyman, which saves on labor costs.
Better optimization of the orientation and inclination of the panels, easily adjustable to best capture the sun's rays all year round.
Disadvantages to be aware of :
A higher risk of damage (impacts from balls, stones, animals).
Different subsidies : In France, financial aid is often less advantageous for ground-based installations than for rooftop installations. It is therefore crucial to be well informed about financial aid before choosing this option, in order to avoid unpleasant surprises.
Despite these specificities, floor installation can be an excellent solution, especially if you have sufficient space and want more control over installation and maintenance.
10. Not training, the source of all mistakes
This tenth mistake is actually the basis for all the others. Relying solely on a solar installer without having a minimum of knowledge about solar energy is the most dangerous trap. As the expert explains, a solar installation is a significant investment, and it's essential to understand the basics, prices, issues, and benefits.
Many homeowners are unaware of key aspects, such as the fact that their system will not work in the event of a power outage if they don't have a hybrid inverter . This lack of knowledge often leads to frustration, feelings of being ripped off , and conflicts with installers. The expert cites the example of friends who were convinced they had been cheated when they simply didn't order the right equipment because they didn't do enough research. The installer, however, delivered what was ordered.
To avoid these disappointments, solar training is essential. You don't need to become a photovoltaic , but you must:
Understand the general operation : how energy is captured, transformed and used.
Know the types of solar equipment : inverters, batteries, panels, and their implications.
Estimate costs : get an idea of market prices to evaluate quotes.
Understand common issues : shading, sizing, maintenance.
By training, you become an informed player in your project, capable of asking the right questions, understanding the answers, and making informed decisions. This is the best way to avoid costly mistakes and maximize the return on investment of your solar installation.
Drastic reduction in electricity bills: Self-consumption considerably reduces your dependence on the network and your expenses.
Increased energy autonomy: Maintains power supply even in the event of a network outage (with hybrid inverter).
Positive ecological impact: Reduction of your carbon footprint and contribution to the energy transition.
Property valuation: A well-designed solar installation can increase the value of your home.
Control your consumption: Encourages awareness and more effective management of your electrical habits.
Possibility of reselling surplus: The surplus electricity produced can generate additional income.
Variety of installation options: The panels can be installed on the roof or on the ground, offering good flexibility.
Long equipment life: Panels and inverters are designed to last for several decades, ensuring a long-term return on investment.
High initial cost: The initial investment for a complete solar installation represents a significant sum.
Complexity of sizing: Crucial to avoid over or under sizing, a source of financial losses.
Risk of scams: Requires great vigilance against unscrupulous installers.
Weather Dependence: Production varies, making total autonomy difficult without additional cost.
Potential impact on roof structure: Improper installation can compromise the waterproofing and integrity of the roof.
Need for regular maintenance: Panels must be cleaned and the installation checked for optimal performance.
Changing regulations and subsidies: Rules may change, impacting long-term profitability.
Visual and spatial clutter: Panels can detract from the aesthetics of a home or take up floor space.
| Stage | Description |
|---|---|
| 1. Evaluate your energy consumption | Analyze your electricity bill over the past 1 to 2 years. Identify your main uses (heating, household appliances, etc.). Take seasonal variations into account. |
| 2. Study your solar potential | Conduct a solar study (orientation, tilt, shadows). Check the optimal placement of the panels (roof, ground, other). Use online tools or consult a professional. |
| 3. Choose the right equipment | Choose quality solar panels that meet your needs. Consider a hybrid inverter to ensure autonomy. Consider batteries to store energy. |
| 4. Compare offers and installers | Request multiple detailed quotes. Check the installers' reputation and certifications. Avoid overpriced proposals. |
| 5. Find out about financial aid | Check local, regional, and national grants. Ask about specific conditions (roof vs. ground). |
| 6. Plan the installation | Choose the ideal time (often outside of winter). Organize the schedule with the installer. Monitor the site to ensure proper execution. |
| 7. Train and inform yourself continuously | Follow reliable resources to understand the basics of solar energy. Learn how to read your production records. Learn about maintenance. |
| 8. Post-installation monitoring | Regularly check production and operation. Contact your installer if there are any problems. Maintain the panels (cleaning, inspections). |
Conclusion
The world of solar energy offers tremendous opportunities to reduce energy dependence and achieve substantial savings . However, the complexity of this solar technology methodical and informed approach .
By avoiding these ten common mistakes, from optimizing your consumption to solid prior training , profitable photovoltaic project that is perfectly suited to your needs.
Investing in solar energy also means investing in your knowledge of the subject to make informed and sustainable choices.
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