UNI-T UT381PV vs UT383S – Solar Irradiance Meter or Lux Meter Malaysia
UNI-T UT381PV vs UT383S – Solar Irradiance Meter or Lux Meter Malaysia
Content
The UNI-T UT381PV and UNI-T UT383S both measure light-related conditions, but they are designed for different applications.
The UT381PV is a solar irradiance meter for photovoltaic installation and maintenance. The UT383S is a digital illuminance meter for checking visible-light levels in workplaces and buildings.
Choosing the correct model depends on whether the user needs to evaluate solar energy or human lighting conditions.
Main Difference
The simplest distinction is:
- UT381PV: Measures solar irradiance in W/m²
- UT383S: Measures visible illuminance in lux and foot-candles
Solar irradiance represents the solar power reaching a surface. Illuminance represents how bright a surface appears to the human eye.
These measurements should not be treated as interchangeable.
What Is the UNI-T UT381PV Used For?
The UT381PV is designed for photovoltaic applications such as:
- Rooftop solar installation
- Solar farm maintenance
- PV system commissioning
- Solar panel troubleshooting
- Panel-temperature monitoring
- Tilt-angle verification
- Panel-direction checking
- Solar laboratory testing
It measures:
- Solar irradiance: 0 to 1400 W/m²
- Temperature: −40°C to 120°C
- Inclination: −90° to +90°
- Azimuth: 0° to 360°
It also provides data storage, Bluetooth connection to the iENV App and outdoor protection.
What Is the UNI-T UT383S Used For?
The UT383S is intended for illuminance measurement in applications such as:
- Offices
- Factories
- Warehouses
- Schools
- Libraries
- Retail premises
- Hotels
- Hospitals
- Indoor work areas
- Building-lighting inspections
Its lux reading helps determine whether an area has sufficient visible light for people to work, move or carry out specific tasks.
It is not primarily designed to evaluate the solar energy available to a photovoltaic panel.
Application Comparison
| Test Requirement | UNI-T UT381PV | UNI-T UT383S |
|---|---|---|
| Solar irradiance in W/m² | Yes | No |
| Workplace illuminance in lux | No | Yes |
| Foot-candle measurement | No | Yes |
| Solar panel temperature | Yes | No |
| Ambient temperature | Yes | No |
| Panel inclination | Yes | No |
| Panel azimuth | Yes | No |
| PV installation work | Yes | Not the main application |
| Office and factory lighting | Not the main application | Yes |
| Solar farm maintenance | Yes | No |
The two models serve different professional users and should not be selected based only on their ability to respond to light.
Why the UT383S Is Not a Substitute for the UT381PV
A lux meter measures visible light according to the sensitivity of the human eye.
Photovoltaic panels respond to solar energy across a broader spectrum. Therefore, a lux reading cannot be reliably converted into a professional W/m² irradiance result under every condition.
The relationship changes with:
- Sunlight spectrum
- Cloud cover
- Haze
- Time of day
- Atmospheric conditions
- Artificial light source
- Sensor characteristics
For PV performance testing, use a dedicated solar irradiance meter such as the UT381PV.
Why the UT381PV Is Not a Substitute for the UT383S
The UT381PV measures solar irradiance for photovoltaic work. It is not intended to verify whether an office, factory or classroom meets a required illuminance level.
For workplace-lighting applications, the measurement normally needs to be expressed in lux.
Use the UT383S when checking:
- Lighting uniformity
- Workstation illumination
- Indoor safety
- Production-area lighting
- Commercial premises
- Building-lighting performance
The measurement should follow the relevant lighting-assessment procedure.
Choose the UT381PV When You Need To
Choose the UNI-T UT381PV when you need to:
- Compare solar irradiance with PV output
- Check panel surface temperature
- Measure ambient temperature
- Verify panel tilt
- Confirm panel direction
- Record changing outdoor solar conditions
- Troubleshoot low PV generation
- Conduct solar commissioning work
Its IP65 rating, UV-resistant housing and two-metre drop resistance support outdoor use.
Choose the UT383S When You Need To
Choose the UNI-T UT383S when you need to:
- Measure indoor or outdoor illuminance
- Check workplace-lighting levels
- Compare brightness at different locations
- Inspect factory or warehouse lighting
- Evaluate office and commercial lighting
- Record lux or foot-candle readings
It is the more suitable instrument when the customer’s concern is lighting for human activities.
Do You Need Both Instruments?
Some contractors, facility teams and safety departments may require both.
For example, a commercial building may need:
- UT381PV for rooftop solar-panel inspection
- UT383S for office, factory and warehouse lighting checks
The instruments cover different parts of the facility’s energy and environmental inspection requirements.
For assistance choosing between the UNI-T UT381PV and UT383S for your application in Malaysia, contact MTM Precision.
MTM Precision Sdn Bhd
Showroom & Service Centre: No. 29-1 & 29-2, Jalan Bandar 18, Pusat Bandar Puchong, 47160 Puchong, Selangor, Malaysia
Tel: 03-8080 7172
WhatsApp: +6016-660 7346
Email: mtmpre@yahoo.com
Website: www.mtmpre.com.my
30 Sep 2026
