7 Checks in the PVSyst Manual to Prevent Missing Settings

Table of Contents

• Approach to Preventing Missing Settings in the PVSyst Manual

• Check 1: Confirm project conditions and regional information

• Check 2 Confirm the selection of meteorological data and solar radiation conditions

• Check 3 Prevent missing input of azimuth and tilt angles

• Check 4: Verify the combination of modules and power conditioners

• Check 5: Do not leave the initial values of the loss conditions unchanged.

• Check 6: Verify shadow settings and the reflection of surrounding obstacles

• Check 7: Review the results screen before outputting the report

• Operational rules to prevent configuration omissions

• Summary for Mastering the PVSyst Manual in Practice

Approach to Preventing Configuration Omissions in the PVSyst Manual

If you want to know the seven checklist items in the PVSyst manual to prevent missing settings, you may be unsure where to check as you proceed with a photovoltaic (PV) system simulation. PVSyst is a practical design-support tool used for PV energy yield forecasting, loss analysis, equipment configuration review, report generation, and more, but because it has many input fields, it is easy to miss settings until you become familiar with it.

The difficulty of PVSyst is not simply that there are many screens. Each individual setting influences the final energy output, loss rates, system configuration, and economic assessment. For example, even a slight offset in the regional information can change the assumed solar irradiance. If the azimuth or tilt angle is entered incorrectly, the pattern of annual energy production will change. If you forget to reflect the shading settings, you may obtain results that look better than reality.

Therefore, when reading the PVSyst manual, it is more important to decide on the practical points to check first than to try to memorize all the explanations in detail from the beginning. The manual is effective not only as a dictionary but also when used as a checklist to prevent omissions in settings.

What beginners often stumble over is that fields that appear to be filled on the screen may actually still be set to their default values. Default values are provisional settings to allow you to proceed and do not necessarily reflect the specific conditions of each project. In PVSyst, multiple settings—such as meteorological data, orientation, equipment, losses, shading, and report conditions—interact and are reflected in the results. If even one is missing, the overall reliability of the simulation is reduced.

In this article, while referring to the PVSyst manual, we outline seven key items to check in practice to avoid overlooked settings. Rather than memorizing the exact names of interface screens, we focus on what to check, why each check is necessary, and what kinds of mistakes are likely to occur. This will be useful not only for people encountering PVSyst for the first time but also for those who have used it before yet feel uncertain about the checks to perform before generating reports.

Check 1 Confirm project conditions and regional information

The first thing to confirm is the project conditions and regional information. In PVSyst, when creating a project you set conditions such as the installation site, latitude and longitude, elevation, time zone, and region name. These can sometimes be modified later, but if you proceed with incorrect conditions at the start, it will affect the choice of meteorological data and solar irradiation conditions, so it is important to verify them early.

When reviewing the PVSyst manual, you need to be aware not only of the project creation workflow but also of which calculations use the location information. The installation site is not just an address; it is a set of basic conditions that affect solar elevation, azimuth, irradiance, temperature, and power generation estimates. In particular, for large-scale projects and ground-mounted installations, how on-site coordinates and elevation are handled can influence the results.

A common configuration oversight is proceeding with a simulation while a provisional region is still selected. Even if you think you have chosen a similar region, differences in solar radiation and temperature conditions can affect the results. Also, within the same prefecture, coastal areas, mountainous areas, and urban areas can have different meteorological conditions. You should check, with reference to the manual, whether the regional data used for the project are close to the actual installation site.

Another thing to watch out for is project names and version control. In PVSyst, you may compare several design proposals or different conditions. In such cases, if the project name or variant name is ambiguous, it will be unclear later which conditions were used for the calculations. To prevent missing settings, not only the input fields but also file names and naming rules for design proposals are important.

For example, keeping differences in the name — such as initial version, revised version, after shading is applied, after equipment changes, and after loss review — makes it less likely you'll get confused when preparing reports. When reading the PVSyst manual, don't just study the operation procedures; also adopt the mindset of organizing data on the assumption that you'll be handling multiple scenarios, which helps reduce mistakes in practice.

When verifying project conditions, review whether the installation site is correct, whether the latitude and longitude match the intended values, whether the elevation and local weather conditions seem appropriate, and whether the project name and design proposal name are properly organized. Carefully checking these items makes it easier to confirm settings in later stages.

Check 2 Confirm how to select meteorological data and solar radiation conditions

Next, what we need to check are the meteorological data and the solar radiation conditions. In PVSyst’s energy-yield simulations, meteorological data such as irradiance, ambient temperature, and wind speed are important prerequisites. No matter how correctly the equipment settings are configured, if the chosen meteorological data are inappropriate, the reliability of the final results will be reduced.

When reading the PVSyst manual, it is important not only to understand how to import meteorological data but also to check what characteristics the selected data possess. Meteorological data come in various types, such as observational data, satellite-based data, and standard year data. Each type has its own characteristics, and you need to choose among them according to the project's objectives.

A common omission in settings is adopting the initially displayed meteorological data as-is. When data appears selected on the screen, it can look as though the configuration is complete. However, whether that data is appropriate for the target location is not automatically guaranteed. If you are using data from a distant site or have chosen data from an area with significantly different terrain conditions, you should be careful about the results.

Also, with solar radiation conditions, it is necessary to understand concepts such as horizontal-plane irradiance, tilted-plane irradiance, diffuse irradiance, and direct irradiance. The PVSyst manual provides explanations for each item, but beginners can easily become confused if they only follow the terminology. In practice, it is important to have a general understanding of how the input meteorological data are converted into irradiance on the tilted plane and used in power generation calculations.

Especially for rooftop installations and projects in mountainous areas, nearby meteorological conditions may not match on-site conditions. In high-temperature regions, temperature losses tend to be larger, and in snowy regions special care is required when handling winter generation and loss conditions. Rather than accepting PVSyst results at face value, practitioners should verify that the assumptions behind the meteorological data match the realities of the project.

When using them for report submission or internal review, it's also important to be able to explain which meteorological data were used. If, upon later review, you cannot determine whether differences in power generation are due to equipment configuration or to differences in the meteorological data, it becomes difficult to make comparisons.

When checking meteorological data, review the distance to the site, elevation difference, types of data, the time period, and whether the trends in solar radiation and temperature show any anomalies. The PVSyst manual can be used as a basic reference for performing this check.

Check 3 Prevent omissions in entering azimuth and tilt angles

The third item to check is the azimuth and tilt angles. The power output of a solar PV system varies greatly depending on which direction the panels face and at what angle they are installed. In PVSyst, these settings are treated as basic system parameters, so any omissions or input errors will directly affect the simulation results.

When consulting the PVSyst manual, you should always check how the azimuth reference is defined. Although we commonly describe orientations as south-facing, east-facing, or west-facing, the software requires these to be entered as angles. Misunderstanding the azimuth reference can result in calculations being performed for the opposite orientation to what you intended.

The same applies to tilt angles. You may convert roof pitch into an angle, or enter the angle directly from the mounting design, but different documents may use different notations. If pitch, degrees, and ratio notations are mixed, mistakes are easily made during data entry. Before entering data into PVSyst, it is important to check how angles are expressed in the design drawings and on-site documents.

A common omission is proceeding to the final report with calculations still based on a provisional angle. In initial assessments it is common to use a typical angle for estimates, but if you forget to update it later to the actual roof pitch or rack angle, the results will diverge from reality. This is especially common when comparing multiple options — some proposals may end up with their angles left outdated.

In projects with multiple roof surfaces, the azimuth and tilt angles may differ for each surface. It is necessary to determine whether the system can be treated as a single-direction system or needs to be divided into multiple sub-arrays. Check the PVSyst manual for how sub-arrays and multiple surfaces are handled, and review whether the inputs reflect the actual conditions of the project.

In ground-mounted projects, even if they appear uniformly south-facing, the optimal angle can vary depending on the slope of the developed land and the arrangement of the racking. In agrivoltaic and sloped-site projects, because land use and construction conditions must be considered in addition to solar irradiation, it is important to determine how closely to align the simulation angle settings with reality.

When checking azimuth and tilt angles, review consistency with the design drawings, differences between roof surfaces, any remaining provisional inputs, the units used to express angles, and how multiple surfaces are handled. This item may seem simple, but because it has a large impact on results, it is a point that should always be checked when verifying PVSyst settings.

Check 4: Verify the combination of modules and power conditioners

The fourth item to check is the combination of the solar PV modules and the power conditioner. In PVSyst, you set the module performance, the number of modules, the string configuration, the power conditioner capacity, the input voltage range, and so on. If these are not appropriately matched, it will affect not only the energy yield but also the viability of the system.

When reading the PVSyst manual, you need not only the method for selecting equipment but also the viewpoint to verify that the selected equipment data matches the design. If multiple similar model numbers exist in the database, you may accidentally select a device with different specifications. It is important to confirm that values such as model number, output, temperature characteristics, voltage, and current match the specification sheet that will actually be used.

Particular attention should be paid to the number of modules and the string configuration. In PVSyst you enter the number of modules in series, the number of parallel strings, sub-array configurations, and so on. If you enter values here that differ from the design drawings or the single-line wiring diagram, the system capacity and its relationship with the power conditioner will change. Even if no error appears on the screen, the setup may still differ from the actual design.

A common configuration omission is failing to modify related settings after changing equipment. For example, modules may be switched to higher-output models while the number of modules or the number of strings is left unchanged. There are also cases where the power conditioner has been replaced but the number of input circuits or the capacity ratio have not been checked. PVSyst may warn about some inconsistencies, but it does not judge the design intent itself.

Also, you need to check the ratio of DC capacity to AC capacity. If oversizing is assumed, it affects energy production and clipping losses. Oversizing is not necessarily bad, but you need to distinguish whether it was set intentionally or occurred as a result. Referring to the PVSyst manual and understanding the meaning of system capacity, capacity ratio, and loss display will make it easier to explain the results.

Equipment data may vary in specifications even for the same manufacturer or the same series. When using old data or approximate data, you need to consider how much to explain in the report. While rough estimates for internal review may be acceptable, more rigorous verification is required for documents submitted to clients or for materials intended for financial institutions.

When verifying modules and power conditioners, check model numbers, specification values, quantities, string configurations, input voltage ranges, capacity ratios, and recheck after any equipment changes. Use the PVSyst manual to understand the meaning of each input field, and treat this not as mere data entry but as a consistency check of the design conditions.

Check 5: Do not leave the initial values of loss conditions unchanged

The fifth item to check is the loss conditions. In PVSyst, you can set various losses such as temperature losses, wiring losses, mismatch losses, soiling losses, degradation, and equipment losses. Because these significantly affect the final energy production, it is important not to proceed with the initial values.

When reading the PVSyst manual, you need to understand what each loss means. The loss items may look technical, but in practice each one corresponds to specific site and design conditions. If wiring distances are long, wiring losses can increase. Installation conditions that tend to get hot will result in larger temperature losses. If there is sand and dust, bird damage, snow accumulation, or coastal salt-spray environments, soiling and maintenance conditions must also be considered.

A common omission is leaving the loss conditions at their default values. Default values are convenient placeholders used to run the simulation and do not necessarily reflect the actual conditions of each project. While the defaults are not necessarily grossly wrong, you should avoid a situation where you cannot explain why those values were used.

Wiring losses in particular tend to change as the design progresses. In the initial assessment stage, approximate values are used, and in the detailed design stage they may be reviewed based on cable length and cross-sectional area. If the PVSyst settings are not updated at that time, reports may be generated using the old assumptions.

Temperature losses also require attention. The module installation method, ventilation conditions, roofing material, racking height, and the surrounding environment affect how module temperatures rise. Installations close to the roof surface and ground-mounted racking can result in different thermal conditions even for the same module. Check the temperature model and the meanings of the input items in the PVSyst manual, and review whether the conditions are appropriate for the project.

The handling of soiling losses and snowfall also varies by region. In some areas rainfall easily washes away soiling, while others have a lot of dust, are more affected by birds, or experience reduced winter generation due to snow. Treating these factors with a single uniform value can lead to discrepancies with actual conditions.

When checking loss conditions, review whether they remain at the initial values, whether there is project-specific justification, whether they have been updated after design changes, and whether the values can be explained in the report. The PVSyst manual is a section you should always consult to confirm the meanings of the loss items.

Check 6 Confirm shadow settings and the reflection of surrounding obstacles

The sixth item to check is the shading settings. In solar power generation, shadows are caused by surrounding buildings, trees, utility poles, mountains, rooftop equipment, parapets, adjacent racking rows, and so on. If a simulation is run without accounting for the effects of shading, the estimated power generation may be higher than the actual output.

The PVSyst manual lets you review settings such as near shading, far shading, 3D scenes, and obstructions. Shading settings can often feel difficult for beginners, but because omissions in the settings have a significant impact on the results, these are points you should always check.

A common setup omission is performing calculations without configuring shadows even for projects that require consideration of shadow effects. In particular, for rooftop installation projects it is easy to overlook shadows cast by surrounding buildings, rooftop equipment, railings, and roof penthouses. For ground-mounted projects, shading from front and rear rows, nearby tree lines, and terrain-induced shading on sloped sites can be problematic.

When configuring shadows, it is not always best to reproduce everything in excessive detail. In practice, you determine how far to model based on the purpose of the simulation. Simplifications may be acceptable for preliminary estimates, but when the simulation is used for final design or profitability assessments, obstacles that affect power generation should be reflected as accurately as possible.

When using the PVSyst manual, it's a good idea to check not only how shadows are entered but also how shadow losses are displayed on the results screen. Even if you believe you have entered shadow settings, they may not be reflected in the calculation results, or the relationship to the target array may not be configured correctly. After entering settings, always confirm on the results screen that the shadow losses are being reflected as intended.

Also, consistency with on-site survey materials is important. Based on site photographs, drone surveys, drawings, terrain data, and information on the heights of surrounding buildings, verify the potential for shading. Before reproducing it in PVSyst, you need to understand what elements are causing the shading in the first place.

When checking shadows, review whether surrounding obstructions have been identified, whether near- and far-field shadows are treated separately, whether the 3D model does not significantly deviate from actual conditions, whether shadow losses are reflected in the results, and whether there is consistency with on-site documentation. Shadow setup is time-consuming, but it is a very important item for preventing omissions in configuration.

Check 7: Review the results screen before generating the report

The seventh item to check is reviewing the results screen before outputting the report. In PVSyst you can export the simulation results as a report, but before generating the report it is important to verify the numerical validity on the results screen. Even if you have configured all input items, if the final results feel off there may still be some missed settings or input errors.

When reading the PVSyst manual, it is important not only to learn how to operate the report output but also to understand the meaning of the items displayed on the results screen. Annual energy production, specific yield, performance ratio, breakdown of losses, and monthly energy production are important clues for checking the settings.

A common mistake is feeling reassured simply because a report can be generated. A report being produced is not the same as its contents being correct. Because PVSyst produces results based on the entered conditions, the calculations themselves may still succeed even if there are errors in the input conditions. Therefore, you need to check the trends of the results before outputting.

For example, if the annual power generation is higher than expected, shadows or losses may have been omitted. Conversely, if it is too low, there may be issues with the azimuth angle, tilt angle, equipment configuration, meteorological data, or loss conditions. If the month-by-month generation trend looks suspicious, you should review the seasonal solar irradiance, shading, snow accumulation, and temperature conditions.

The breakdown of losses is also important. In PVSyst you can check how much loss each factor contributes. If you notice anything odd here—such as wiring losses being extremely small, shading losses showing zero, or temperature losses not matching your expectations—recheck the settings. Lower losses make the results look better, but unrealistically low losses that do not reflect reality are actually a risk.

The report also displays the design conditions and the data used. Before submission, verify that the project name, installation location, equipment name, capacity, azimuth, tilt, weather data, loss conditions, and so on are as intended. It is not uncommon for errors to be found at this stage. Rather than viewing the report as a mere deliverable, it is important to use it as the final checklist for confirming settings.

Before generating the report, review the annual energy production, monthly energy production, performance ratio, breakdown of losses, shading losses, equipment configuration, and project conditions. Using the PVSyst manual to understand the meaning of each result item makes it easier to notice any anomalies in the numbers.

Operational rules to prevent configuration omissions

To prevent omissions in PVSyst settings, it is important not only to memorize individual operations but also to organize the way the work is carried out. No matter how much you read the manual, if the method of checking changes with each task, it becomes difficult to completely prevent mistakes. In practice, establishing operational rules for before and after using PVSyst can reduce missing settings.

The first and most important thing is to organize the input documents before starting work. If you prepare in advance the installation location, drawings, equipment specifications, the meteorological data policy, shading documentation, wiring conditions, loss conditions, and so on, you will need to repeat provisional entries in PVSyst less often. If you proceed with insufficient documentation, you will create more provisional settings intended to be corrected later, and those provisional settings remaining in place can lead to missed configurations.

Next, it is important to record the conditions for each design option. The variant name inside PVSyst alone may not be enough to capture the subtle differences. Keep separate notes on which module was used for each option, what loss values were set, whether shading was applied, and whether the meteorological data were modified.

Also, after carrying out changes, it is necessary to make a habit of checking related items together. When you change the module, check the capacity, string configuration, and consistency with the power conditioner. When you change the installation angle, check the changes in solar irradiance and power generation. If you add shading, check the loss breakdown. In this way, reviewing related items as a set for each change makes it easier to prevent omissions in settings.

The PVSyst manual can be used not only as a reference when you run into problems but also as material for creating in-house checklists. Rather than memorizing each feature description in the manual exactly, focus on the items you frequently use in your company’s projects and create verification procedures, which makes it easier for them to become part of everyday practice.

Review processes are also important. If only the creator checks the work, it is easy to overlook items you thought you had entered. If possible, establish a step in which a different person verifies the report and the configuration settings. Independent verification is especially effective for materials submitted to clients, for financial institutions, or for internal investment decision documents.

Furthermore, it can be helpful to examine differences from past projects. When comparing with past projects of similar scale, region, and installation conditions, verify the reasons if power generation or loss rates differ significantly. Of course, conditions vary for each project, but if there are extreme differences, input errors or omitted settings may be the cause.

In operations that prevent configuration omissions, it is important to combine pre-input document organization, verification of related items when conditions change, naming of design proposals, checking differences in results, and third-party reviews. Mastering PVSyst is not simply being able to operate the interface; it means being able to explain the basis for the results.

Summary for Mastering the PVSyst Manual in Professional Practice

To prevent omissions in settings in the PVSyst manual, it is more important to prioritize checking the items that are likely to affect results in practice rather than trying to understand all functions at once. In particular, project conditions, meteorological data, azimuth and tilt angles, equipment configuration, loss conditions, shading settings, and reviewing results before report output are items that are prone to being overlooked and have a large impact on the results.

PVSyst is a high-functionality simulation tool, but it performs calculations faithfully based on the input assumptions. In other words, if the settings are correct it will provide a valid basis for consideration, but if there are omissions in the settings, the results will include those omissions. The software does not automatically determine the overall validity of the design. That is precisely why it is necessary to cross-check the input conditions against the results while using the manual.

When beginners use PVSyst, they tend to focus first on the operational procedures. Remembering which buttons to press and which screens to navigate to is of course important. However, what really matters in practice is understanding why a particular setting is entered, what that value affects, and judging whether the output results seem reasonable.

To prevent configuration omissions, it is effective to use the PVSyst manual not simply as a user guide but as a checklist. After creating a project, check the site information. After selecting meteorological data, verify its consistency with the target location. After entering the azimuth and tilt, cross-check them against the drawings. After choosing equipment, confirm the specifications and the string configuration. After entering loss conditions, check that they are not left at their initial/default values. After setting shading, verify that it is reflected in the results. Before issuing the report, review whether the energy production and loss breakdown show any inconsistencies. By following this sequence every time, you can greatly reduce mistakes.

Also, in photovoltaic system design there is a lot of information that cannot be completed by PVSyst settings alone. Cross-checking with external documents—site conditions, drawings, equipment specifications, construction conditions, maintenance conditions, and the surrounding environment—is indispensable. While confirming the meaning of the screens in the PVSyst manual, verifying that the actual site conditions match the input values leads to a reliable simulation.

Ultimately, the important thing is to be able to explain the numbers in the report. Why was this meteorological data used, why these loss values, to what extent was shading taken into account, does the equipment configuration match the drawings, and what justifies judging the energy production as reasonable? If you can explain these points, the PVSyst results become not merely calculation outputs but documentation that supports design decisions.

Incorporating the PVSyst manual’s seven checks to prevent omitted settings into your workflow makes it easier to improve the accuracy of preliminary studies, detailed design, report preparation, and internal reviews. If the large number of settings makes you uneasy, it is especially important to use these seven items as your basic checkpoints and to review them in the same order each time. The first step to using PVSyst correctly is not to memorize all its complex features, but to develop the habit of consistently checking the important settings so none are missed.