{"id":9517,"date":"2026-09-15T15:35:16","date_gmt":"2026-09-15T07:35:16","guid":{"rendered":"https:\/\/www.yantaisensor.com\/?p=9517"},"modified":"2026-09-16T09:41:36","modified_gmt":"2026-09-16T01:41:36","slug":"class-a-vs-class-b-pyranometers","status":"publish","type":"post","link":"https:\/\/www.yantaisensor.com\/zh\/blog\/class-a-vs-class-b-pyranometers","title":{"rendered":"A\u7ea7\u4e0eB\u7ea7\u603b\u8f90\u5c04\u8868\uff1a\u60a8\u9700\u8981\u54ea\u4e00\u79cd\uff1f"},"content":{"rendered":"\n

Introduction<\/h2>\n\n\n\n

When selecting a pyranometer<\/mark><\/a> for a solar monitoring project, buyers often face a practical question: Class A vs Class B pyranometers\u2014which one is right for the project? The answer is not simply about choosing the more accurate or more expensive sensor. It depends on how the irradiance data will be used, what the project specification requires, and how much measurement uncertainty the application can accept.<\/p>\n\n\n\n

Under ISO 9060:2018<\/mark><\/a>, Class A and Class B pyranometers have different performance requirements. Class A is generally selected when tighter measurement performance and long-term data stability are important, while Class B can provide a practical balance for routine PV, meteorological and environmental monitoring.<\/p>\n\n\n\n

In actual projects, the decision also needs to consider the measurement purpose, applicable standard, GHI or POA requirement, installation environment, calibration and communication interface. This article explains the practical difference between Class A and Class B and helps buyers determine which pyranometer is appropriate for their application.If you are comparing different pyranometer technologies, see our guide to thermopile vs silicon pyranometers<\/mark><\/a> for a closer look at their differences and selection criteria.<\/p>\n\n\n\n

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\"XF500S-CWB-compact-weather-sensor-for-solar\"<\/figure>\n\n\n\n
\"XF500S-CWB-compact-weather-sensor-for-solar\"<\/figure>\n<\/figure>\n\n\n\n

Class A vs Class B Pyranometers: At a Glance<\/h2>\n\n\n\n

Class A and Class B pyranometers are both classified under ISO 9060:2018, but they are designed for different levels of measurement performance. The table below gives a quick comparison; the specific performance differences and application considerations are discussed in the following sections.<\/p>\n\n\n\n

Factor<\/td>Class A<\/td>Class B<\/td><\/tr>
Performance level<\/td>Higher<\/td>Intermediate<\/td><\/tr>
Measurement requirements<\/td>More stringent<\/td>Less stringent<\/td><\/tr>
Long-term stability<\/td>Tighter<\/td>Less stringent<\/td><\/tr>
Response and directional performance<\/td>Tighter<\/td>Less stringent<\/td><\/tr>
Typical use<\/td>Reference and critical PV monitoring<\/td>Routine PV and environmental monitoring<\/td><\/tr>
Cost<\/td>Generally higher<\/td>Generally lower<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
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\"Class<\/figure>\n\n\n\n
\"Class<\/figure>\n<\/figure>\n\n\n\n

What Does ISO 9060:2018 Mean for Pyranometer Classes?<\/h2>\n\n\n\n

When comparing Class A vs Class B pyranometers, ISO 9060:2018 is the main reference for understanding their performance classification. The standard uses Class A, Class B and Class C and evaluates pyranometers against several performance parameters rather than assigning a class from one overall accuracy value. This gives buyers a clearer basis for comparing a solar radiation sensor for different measurement requirements.If you want to see how IEC 61724 affects PV monitoring and sensor selection, our [IEC 61724 Guide<\/mark><\/a>] provides a practical overview.<\/p>\n\n\n\n

ISO 9060:2018 Defines Class A, B and C<\/h3>\n\n\n\n

ISO 9060:2018 replaced the Secondary Standard, First Class and Second Class terminology used in ISO 9060:1990 with the Class A, Class B and Class C system. The classification covers response time, zero offset, non-stability, nonlinearity, directional response, spectral error, temperature response and tilt response.<\/p>\n\n\n\n

The main Class A, B and C limits include:<\/p>\n\n\n\n

Performance Parameter<\/td>Class A<\/td>Class B<\/td>Class C<\/td><\/tr>
Response time (95%)<\/td><10 s<\/td><20 s<\/td><30 s<\/td><\/tr>
Zero offset A<\/td>\u00b17 W\/m\u00b2<\/td>\u00b115 W\/m\u00b2<\/td>\u00b130 W\/m\u00b2<\/td><\/tr>
Non-stability<\/td>\u00b10.8%<\/td>\u00b11.5%<\/td>\u00b13%<\/td><\/tr>
Nonlinearity<\/td>\u00b10.5%<\/td>\u00b11%<\/td>\u00b13%<\/td><\/tr>
Directional response<\/td>\u00b110 W\/m\u00b2<\/td>\u00b120 W\/m\u00b2<\/td>\u00b130 W\/m\u00b2<\/td><\/tr>
Clear-sky GHI spectral error<\/td>\u00b10.5%<\/td>\u00b11%<\/td>\u00b15%<\/td><\/tr>
Temperature response<\/td>\u00b11%<\/td>\u00b12%<\/td>\u00b14%<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

These values represent selected acceptance limits used in the ISO 9060:2018 pyranometer classification. The complete classification also includes other conditions, such as additional zero-offset criteria, tilt response and signal-processing error. They should not be treated as a single overall accuracy specification.<\/p>\n\n\n\n

Class A and Class B Are Not Defined by One Accuracy Number<\/h3>\n\n\n\n

A common mistake when comparing pyranometers is to reduce the classification to a statement such as \u201cClass A is \u00b12% and Class B is \u00b13%.\u201d ISO 9060 does not define the classes this way. Pyranometer accuracy depends on several performance characteristics, so the stated ISO class, technical specifications and calibration information should be checked together when selecting a sensor.<\/p>\n\n\n\n

What Do \u201cSpectrally Flat\u201d and \u201cFast Response\u201d Mean?<\/h3>\n\n\n\n

ISO 9060:2018 also introduced additional attributes that can be used with the main class designation. Spectrally flat indicates that the pyranometer meets the specified spectral selectivity requirement over the relevant wavelength range. Fast response applies to instruments with a 95% response time below 0.5 s. These attributes can be useful when the monitoring system needs better control of spectral effects or needs to capture rapid changes in solar irradiance.<\/p>\n\n\n\n

For buyers, the practical question is not simply whether Class A or Class B is higher. The more useful question is whether the pyranometer’s performance matches the measurement purpose, applicable project standard and required data quality.<\/p>\n\n\n\n

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\"XF500S-CWB<\/figure>\n\n\n\n
\"XF500S-CWB<\/figure>\n\n\n\n
\"XF500S-CWB<\/figure>\n<\/figure>\n\n\n\n

Class A Pyranometer: When Do You Need It?<\/h2>\n\n\n\n

A Class A pyranometer is generally selected when irradiance data needs tighter measurement performance and better long-term consistency. Under ISO 9060:2018, Class A has stricter limits for several performance characteristics, including zero offset, non-stability, nonlinearity, directional response, temperature response and tilt response.<\/p>\n\n\n\n

The practical reason to choose Class A is not simply that it is \u201cmore accurate.\u201d It is that tighter control of different error sources can be valuable when irradiance data is used for technical evaluation, performance analysis or long-term reference measurements.<\/p>\n\n\n\n

When Should You Choose a Class A Pyranometer?<\/h3>\n\n\n\n

Class A is worth considering when:<\/p>\n\n\n\n