Key Points of the PVSyst Manual｜5 Situations Where Beginners Get Stuck

Table of Contents

• Basics to understand before reading the PVSyst manual

• Stumbling scenario 1: Unable to organize prerequisites when creating a project

• Pitfall 2: Misinterpreting meteorological data and location settings

• Stumbling scenario 3: Unsure about azimuth, tilt angle, and array settings

• Stumbling Point 4: Unable to determine how much of the loss settings to input

• Common stumbling block 5: Not knowing how to interpret simulation results and reports

• How to Read the PVSyst Manual for Practical Application

• Checklist for Beginners to Improve Accuracy

• Summary

Fundamentals to Know Before Reading the PVSyst Manual

Many people who consult the PVSyst manual have the goals of carrying out photovoltaic energy-yield simulations themselves, entering design conditions correctly, and understanding the figures in reports so they can be used in internal documents or explained to customers. PVSyst is a specialized software widely used for designing photovoltaic systems and forecasting energy production, and simply following the on-screen prompts can leave users unable to judge the meaning of input values or the validity of results. Therefore, what is important for beginners is not to read the manual from start to finish, but to first understand the places where they are likely to get stuck and to grasp which settings have a major impact on the energy yield.

The first thing to be aware of in the PVSyst manual is that software operation procedures and design decisions are separate. The manual explains the screen items and the flow of inputs, but choosing which values to adopt, how to reflect site conditions in the model, and judging whether the results are realistic all require basic knowledge of photovoltaic power generation. For example, even with the same installed capacity, annual energy production can vary greatly depending on installation location, orientation, tilt angle, shading, temperature, wiring, inverter, soiling, and degradation conditions. While PVSyst lets you input these conditions in detail, its high degree of input freedom makes it easy—especially for beginners—to lose sight of what the settings actually mean.

Also, when reading the PVSyst manual, it is important not to follow only screen names and feature names, but to be aware of the overall flow of the simulation. The basic sequence is to create a project, set the location and meteorological data, enter the system configuration, reflect array and shading conditions, adjust loss conditions, and finally check the simulation results. If assumptions become unclear at any point in this flow, the results of subsequent steps will also be unclear. Especially beginners tend to try to find the cause later by looking only at the report, but in many cases the cause actually lies in the initial project setup or in the selection of meteorological data.

This article highlights five situations in which beginners reading the PVSyst manual are likely to stumble, and clarifies the approach you should take when reading it. Rather than memorizing operational details, understanding the causes of those stumbling blocks will significantly change how you read the manual. It is useful as a basic review for those taking charge of power generation simulations for the first time, those who have inherited a predecessor’s settings, and those who must explain the figures in reports.

Stumbling Scenario 1: Unable to organize prerequisites when creating a project

Beginners following the PVSyst manual often first stumble at the project creation stage. Creating a project may look like simply making a file, but in reality it is an important step that determines the assumptions for the simulation. If the installation site, purpose, system size, connection method, stage of study, design options to be compared, and so on are not organized, the meaning of the conditions entered later becomes ambiguous. PVSyst allows many conditions to be changed afterward, but if you proceed while the initial assumptions remain unclear, it is easy to lose track of what was changed and which results are correct when comparing multiple options.

A particular source of confusion for beginners is the relationship between the project and its variants. In PVSyst, you may handle multiple proposals within the same case that differ in design conditions. For example, comparisons such as changing the tilt angle on the same site, changing module capacity, altering the inverter configuration, or changing the way shading is considered. In this situation, if you do not separate the assumptions that apply to the entire project from the conditions changed for each individual proposal, the purpose of the comparison becomes unclear. When reading the manual, it is also important not to look only at the input fields on the screen but to be aware whether an item is a condition common to the case or a condition specific to each design proposal.

A common mistake when creating a project is starting to enter data without clarifying the objective of the analysis. The required input accuracy varies depending on whether you want to quickly know the estimated energy production, compare design proposals, use it for explanatory materials for financial institutions or customers, or use it for detailed pre-construction studies. For early-stage estimates, you should prioritize the appropriateness of the site, system capacity, orientation, and tilt angle rather than overly detailed loss settings. On the other hand, at stages close to detailed design, you need to carefully check assumptions such as shading, wiring, temperature, inverter sizing ratio, and output control. If the objective remains unclear, you may spend too much time on minor details or, conversely, overlook important settings.

When reading the project creation chapter of the PVsyst manual, it is important not to treat it merely as an operational guide but to read it as guidance for managing simulations. If the project name, site name, design proposal name, creation date, and assumptions are organized so they can be understood later, it becomes easier to compare and explain results. In particular, when multiple people are working on a project or when rechecking past study results, the way files and variant names are given directly affects practical quality. Beginners especially tend to focus on the data-entry work itself, but organizing things so they can be reviewed later ultimately helps prevent mistakes.

Pitfall 2: Misinterpreting the Meaning of Meteorological Data and Location Settings

Another common stumbling block in the PVSyst manual is meteorological data and site settings. In photovoltaic simulations, meteorological conditions such as solar irradiance, temperature, and wind speed have a major impact on power generation. In particular, because solar irradiance forms the basis for annual energy production, the results will vary depending on which meteorological data set you use. Beginners often assume that selecting a location will automatically configure the correct meteorological data, but in reality you need to check the data type, period, representativeness, distance from the installation site, and local terrain conditions.

When configuring a site, it's not enough to simply enter the address and latitude/longitude. You must determine which meteorological data are appropriate for that location. Even when using data from nearby weather stations, solar radiation and temperature trends can differ in mountainous areas, coastal areas, basins, snow-covered regions, or urban areas. For example, within the same prefecture, cloud patterns and temperatures can vary between the coast and the inland. Even data from a nearby observation point may not be representative of the site if the terrain or elevation differs significantly. When reading the PVSyst manual, you should not only learn how to select data but also adopt a perspective for verifying the data's validity.

What often confuses beginners is the meaning of the numbers in meteorological data. You cannot make simple judgments such as “high annual solar irradiation automatically means high profits” or “low temperatures are always advantageous.” In photovoltaic power generation, while greater solar irradiation tends to increase power output, high temperatures raise module temperature, which tends to reduce output. In addition, regional characteristics such as winter snowfall, cloudy weather during the rainy season, and the effects of the typhoon season must be taken into account. Meteorological data are not merely input items; they are the very premises of a design proposal.

To avoid failures in weather data configuration, it is important to note the source of the data used, the period covered, and whether any corrections were applied. If you cannot explain later, when reviewing a report, why that weather data was used, it becomes difficult to demonstrate the reliability of the results. When customers or internal stakeholders ask, "What assumptions underlie this power generation figure?", being able to explain the site and the weather data makes a big difference. Beginners reading the PVSyst manual should first understand that weather data is the foundation of the results and adopt an approach of not relying solely on convenient automatic settings.

Stumbling Point 3: Unsure about azimuth, tilt angle, and array settings

Even within the PVSyst manual, azimuth, tilt angle, and array settings are typical areas where beginners tend to stumble. Because the orientation and angle of solar panels directly affect energy production, mistakes in these settings can have a major impact on results. In Japanese practice, expressions such as south-facing, east–west facing, roof pitch, and mounting-frame angle are commonly used, but in the software they must be entered numerically as azimuth and tilt angles. If you cannot link the on-site expressions with PVSyst’s input method, you may end up simulating a layout that differs from what was intended.

What you need to pay attention to with azimuth is the reference direction and the sign convention. Depending on the software or documentation, some use south as the reference, some use north, and the treatment of east/west signs can differ. When reading the PVSyst manual, you must always confirm which direction the azimuth displayed on the screen is referenced to. A common mistake beginners make is entering angles from drawings or the azimuth they were told on site as-is. For example, even if you are told a roof faces southeast, you must confirm what angle that corresponds to when entering it in PVSyst. Misinterpreting the azimuth changes how solar irradiance is received and can cause the power generation results to deviate significantly.

For the tilt angle, you cannot simply enter an angle and be done. For ground-mounted systems, the tilt is sometimes adjusted toward the optimal angle to prioritize energy yield, but for roof-mounted systems it is common to follow the existing roof pitch. For agrivoltaics, carport-type systems, heavy-snow regions, and high-wind regions, factors beyond energy yield—such as structure, drainage, maintenance, shading, and snow shedding—are also taken into account. The tilt angle in PVSyst is an important parameter for energy-yield calculations, but actual design decisions are made including constructability and safety, so the simulation’s optimal value is not necessarily adopted as the installed value. If this difference is not understood, the design may be judged solely by the software’s energy-yield output.

In array configuration, the number of modules, the number in series, the number in parallel, the combination with the inverter, and how installation surfaces are divided are important. Beginners tend to think that matching only the total capacity is sufficient, but in practice you need to check the string configuration, the inverter’s input range, voltage conditions, and how to handle surfaces with different orientation and tilt. For example, if you lump east- and west-facing surfaces together under the same conditions, you may not be able to accurately represent the actual power generation curve. In projects with multiple roof surfaces or where the array splits to follow the terrain, it is important to carefully organize the conditions for each installation surface.

If you plan to use the PVSyst manual in practice, you should read the azimuth, tilt, and array settings while cross-checking them against drawings and on-site information. Rather than learning the operations from the manual alone, confirming them together with the site plan, layout drawing, single-line wiring diagram, module datasheet, and inverter datasheet will clarify the meaning of the input values. If a beginner finds it difficult to make judgments alone, it is important to check with the design or construction personnel and align the condition names in PVSyst with the actual design conditions.

Stumbling Point 4: Unable to determine how much of the loss settings to input

In the PVSyst manual, the loss settings are what beginners tend to worry about most. Loss settings include various items such as temperature loss, wiring loss, mismatch loss, soiling, shading, degradation, inverter loss, transformer loss, and so on. Because there are many input fields on the screen, some people feel they must configure every detail, while others are unsure whether the default values are acceptable. Loss settings are necessary to bring the estimated energy production closer to reality, but entering figures without a basis can produce results that are difficult to explain.

What beginners should first understand is that the loss settings are not a field for arbitrarily reducing the estimated energy production, but items for modeling real-world generation losses. In actual solar power systems, not all the solar radiation that strikes the modules is converted into electricity. Losses accumulate — for example, output reduction due to temperature rise, voltage drop from wiring, losses during equipment conversion, reductions from shading, and reductions from soiling. In PVSyst you can set these items individually, making it easier to see which losses are large and on what assumptions the energy production is being predicted.

A common mistake when setting losses is stacking unwarranted safety margins. If you inflate soiling, degradation, shading, availability, and other losses to be conservative about energy production, you can end up with estimates that are excessively low compared with reality. Conversely, if you make losses too small to produce an attractive energy figure, the deviation from actual performance will be large. What matters is having an explainable rationale for each loss. You should document why you chose each value, referring to manufacturer data, design conditions, local characteristics, maintenance plans, and past project performance.

Shadow losses require particular attention. PVSyst handles both near shading and far shading, but beginners often assume they can simply input shading as a fixed percentage. However, the effect of shading changes with the time of day, season, solar altitude, surrounding obstacles, and string configuration. Even a small amount of shading can have a large impact on energy yield depending on the module and string layout. When accounting for shadows from buildings, trees, utility poles, fences, or adjacent rows, it is important to check them together with the site layout conditions. When reading the shadow analysis section of the manual, you should consider not only how to build the 3D model but also which shadows need to be represented and to what level of accuracy.

Conditions such as soiling and snow can also vary greatly depending on the region and operating practices. In areas with heavy dust, locations prone to bird damage, sites near farmland or factories, snowy regions, and areas affected by salt damage, standard assumptions may be insufficient. Conversely, if cleaning schedules and maintenance frequencies are clearly defined, it may not be necessary to assume excessively large soiling losses. Beginners reading the PVSyst manual should not be overwhelmed by the number of loss items, but should focus on identifying which items have the greatest impact for each project.

A practical approach to progressing loss settings is to first make a rough estimate using initial or typical values, then reflect project-specific conditions, and finally check sensitivity. For example, by seeing how much annual energy production or the performance ratio changes when you slightly change soiling loss, change wiring loss, or alter shading conditions, it becomes easier to judge which conditions are important. For beginners, understanding the impact of changes leads to learning more than entering perfect values from the start.

Stumbling Point 5: Not Knowing How to Interpret Simulation Results and Reports

After completing the data entry by reading the PVSyst manual, what beginners most commonly stumble on at the end is how to read the simulation results and the report. The results screen shows annual energy production, monthly energy production, performance ratio, loss diagram, energy flow, and device-level values. For first-time viewers it can be difficult to know which numbers to prioritize, which figures are abnormal, and how to explain the report. Being able to complete the input work but unable to explain the meaning of the results becomes a major issue in practical work.

First, what you should check is not to focus too much on annual energy production alone. Annual energy production is an easy-to-understand metric, but by itself it cannot determine the validity of a simulation. You need to check whether the generation is excessively high relative to the installed capacity, whether the month-by-month generation trends match the local climate, whether the difference between summer and winter is reasonable, and whether the effects of shading and temperature losses are being underestimated or overestimated. Even if the annual energy production is close to expectations, if the monthly trends or the breakdown of losses seem inconsistent, you should recheck the input conditions.

The performance ratio is also an important metric. The performance ratio is a concept used to assess how efficiently an actual system generates electricity compared to ideal conditions. However, a high performance ratio is not necessarily always good, nor is a low one necessarily bad. Because it varies with weather conditions, temperature conditions, shading, equipment configuration, and loss settings, it needs to be evaluated together with the project conditions. For beginners, rather than judging solely by the numerical value of the performance ratio, it is important to cross-check why that value occurred against the loss diagram and the configured conditions.

Loss diagrams and the energy flow are particularly useful for understanding PVSyst reports. Because they allow you to check, step by step, at which stages and to what extent losses occur, they make it easier to investigate the causes when generation is lower than expected. For example, if temperature losses are large, check the installation environment and module temperature conditions; if shading losses are large, check nearby obstructions and the layout. If inverter losses or clipping are large, you may need to reassess the balance between DC capacity and AC capacity. When reading the results, it is important not to simply glance at the numbers, but to follow the connections between the input conditions and the losses.

When explaining a report to colleagues or clients, it is easier to communicate if you organize it in the order of assumptions, results, and points to note, rather than simply listing technical terms. If you can explain which location’s meteorological data was used, how the system capacity and installation angle were set, how shading and losses were considered, approximately how much the annual power generation will be, and which conditions should be paid attention to when viewing the results, the report’s credibility will increase. Beginners should not treat producing the report as the goal, but should aim to be able to explain each figure in the report.

How to Read the PVSyst Manual for Practical Use

To make practical use of the PVSyst manual, it's important to approach reading it according to the specific situations where it's needed. Beginners tend to read the manual from the beginning in order and try to understand everything before operating. However, PVSyst has many features, and it's not easy to understand all items at once. First, cover the basic workflow—project creation, meteorological data, system settings, array configuration, loss settings, and result review—and then, depending on the project, delve deeper into the functions you need.

In practice, organizing the input conditions before reading the manual makes the work go more smoothly. By confirming in advance the installation location, system capacity, module specifications, inverter specifications, azimuth, tilt angle, layout drawings, shading factors, assumed loss conditions, and the purpose of the report you want to generate, it becomes clear which parts of the manual you need to read. Conversely, if the prerequisite conditions have not been gathered, reading only the manual will not allow you to determine which values to enter in practice. The PVSyst manual becomes useful in practice only when combined with design information.

Also, when learning to operate PVSyst, your understanding deepens if you not only create a single completed dataset but also perform comparisons by gradually changing conditions. For example, by varying the azimuth, changing the tilt angle, adjusting soiling losses, and comparing scenarios with and without shading, you can directly observe how each setting affects energy production. Items that may feel abstract when you only read the manual become easier to understand when confirmed as differences in results. For beginners, learning through comparison is highly effective.

What is especially important in practice is to retain the input values and the basis for the results. Simulation results created with PVSyst may be used for design decisions, financial assessments, customer explanations, internal approvals, and so on. Therefore, you need to be able to trace later which assumptions the results were based on. Rather than simply saving the report, organizing the meteorological data used, the versions of design drawings, equipment specifications, the rationale for loss settings, and the change history will make later verification easier. The purpose of reading the PVSyst manual is not only to learn how to operate the software, but to create simulations that you can explain.

Checkpoints for Beginners to Improve Accuracy

When you are just starting to use PVSyst, confirming the consistency of basic conditions leads to improved accuracy more than mastering all the detailed functions. The first items to check are system capacity, site, meteorological data, azimuth, tilt angle, and the combination of modules and inverters. Because these greatly affect energy generation, input errors can cause large deviations in the overall results. Pay particular attention to unit mix-ups, differences in azimuth reference conventions, use of outdated specifications, and failures to reflect drawing revisions.

Next, you should verify to what extent the on-site conditions have been reflected. Shadows from surrounding buildings and trees, terrain undulation, segmentation of roof surfaces, snow and soiling, maintenance plans, and so on vary in importance depending on the project. It is not always correct to input every detail, but ignoring conditions that are likely to have a significant impact on power generation reduces the reliability of the results. Beginners should prioritize checking the conditions with large impacts and clearly state smaller-impact conditions as assumptions.

To improve the accuracy of a report, it is also important to cross-check the results against external reference points. Comparing them with past projects' generation, performance in neighboring areas, the typical annual generation range relative to system capacity, and monthly seasonal trends makes obvious anomalies easier to spot. PVSyst's calculation results are useful, but if the input conditions are wrong the results will be wrong. Rather than accepting the software's output as correct at face value, engineers should adopt an attitude of verifying its plausibility.

Additionally, something beginners should do is manage the standard case and comparison cases separately. First create the standard case that you currently consider most reasonable, and then create comparison cases with changed conditions. Doing this makes it easier to see the impact of design changes. For example, you can check how much the results change if you alter the tilt angle, change the inverter capacity, add shading, or adjust loss conditions. When creating comparison cases, make the changes clear and avoid changing too many conditions at once.

When using the PVSyst manual to improve accuracy, it is more realistic to adopt a cycle of checking and correcting rather than aiming for perfect inputs all at once. For the first simulation, first get a grasp of the overall workflow, then review the key conditions, and finally refine the loss assumptions and the clarity of the reports; following this order makes it possible to improve accuracy without undue effort. What beginners should avoid most is filling in numbers without a proper understanding. If there are items you do not understand, proceed while checking how much each item affects the results.

Summary

When organizing the key points of the PVSyst manual for beginners, there are five main situations where people tend to get stuck. These are: being unable to clarify the assumptions when creating a project; misunderstanding the meaning of meteorological data and site settings; getting confused about azimuth, tilt angle, and array settings; being unable to judge how much to enter for loss settings; and not knowing how to interpret simulation results and reports. These are not merely operational mistakes but are related to the way of thinking about power generation simulation.

PVSyst is a powerful software, but it has many input fields, which can make it hard for beginners to know where to start. However, you don't need to learn all the functions at once. First, grasp the basic workflow—site, meteorological data, system configuration, azimuth, tilt, losses, and result verification—and understand how each setting affects energy production. The manual should be used not only to check operational procedures but also to confirm the meaning of input conditions.

To create simulations that are reliable in practice, you must record the rationale for input values, verify the validity of the results, and be able to explain the report. Rather than looking only at annual energy production, understanding deepens by checking monthly trends, the performance ratio, loss diagrams, and the assumptions together. When working while reading the PVSyst manual, it is important not just to follow the on‑screen operations but to consider why you enter a given value and why a given result occurs.

The shortcut for beginners to master PVSyst is to first learn the common stumbling blocks and then check the important settings in order. Clarify the project’s objectives, verify the validity of the meteorological data, cross-check the azimuth and tilt angles against the drawings, provide a rationale for the loss settings, and be able to explain the figures in the report. By keeping this flow in mind, the PVSyst manual becomes not just an operational guide but a practical tool for improving the quality of energy yield simulations.