Pre-Installation Solar Site Survey with UNI-T UT381PV Malaysia
Pre-Installation Solar Site Survey with UNI-T UT381PV Malaysia
Content
A solar site survey should identify the sunlight, shading, roof orientation and installation conditions before the photovoltaic system is finalised.
The UNI-T UT381PV Solar Irradiance Meter helps solar contractors measure irradiance, temperature, inclination and azimuth during residential, commercial and industrial site assessments.
Review the Proposed Installation Area
Start by inspecting the roof or ground area proposed for the solar panels.
Check for:
- Available installation space
- Roof condition
- Roof material
- Roof inclination
- Existing structures
- Water tanks
- Antennas
- Air-conditioning equipment
- Nearby trees
- Adjacent buildings
- Access for future maintenance
Photograph the complete area and any object that may affect the solar installation.
Identify Possible Shading
Shading may reduce the output of one panel, one string or a larger part of the PV system.
Possible shading sources include:
- Trees and vegetation
- Parapet walls
- Roof ridges
- Water tanks
- Communication equipment
- Nearby high-rise buildings
- Electrical structures
- Other rows of solar panels
- Future building extensions
Observe the direction and length of the shadows during the site visit.
One inspection cannot show every seasonal or hourly shading condition, but it can identify obvious risks that require further assessment.
Measure the Available Solar Irradiance
The UT381PV measures solar irradiance from 0 to 1400 W/m².
Position the sensor in the same plane as the proposed solar panel surface. Record the value together with:
- Date
- Time
- Weather condition
- Measurement location
- Roof section
- Visible shading
- Sensor orientation
Do not use a single irradiance reading as a complete prediction of annual solar generation. The reading represents the conditions present at the time of measurement.
Historical solar data and proper system-design software may still be required.
Check the Roof Inclination
The UT381PV measures inclination from −90° to +90°.
Measure the angle of each proposed roof section. Different sections may have different slopes even when they appear similar.
Inclination information helps the installer consider:
- Mounting-system requirements
- Panel-row arrangement
- Access space
- Drainage
- Potential self-shading
- Structural limitations
- Future cleaning and maintenance
The measured angle should be included in the site-survey record.
Confirm the Roof Direction
The UT381PV measures azimuth from 0° to 360°.
Perform compass calibration before recording the direction. Keep the instrument away from large metal objects and strong magnetic sources where possible.
Measure the direction of every roof section under consideration.
Different orientations may produce power at different times of the day. The system designer can use this information when planning panel placement and inverter configuration.
Record Ambient and Surface Temperature
The UT381PV measures temperatures from −40°C to 120°C.
During the site survey, temperature measurement can help document:
- Ambient site conditions
- Roof-surface temperature
- Heat accumulation
- Ventilation limitations
- Differences between roof materials
- Areas near heat-producing equipment
A one-time temperature reading does not represent the full annual operating condition, but it can identify unusually hot areas requiring further consideration.
Compare Multiple Installation Areas
When several roof sections are available, compare them using the same inspection method.
Record:
- Irradiance
- Inclination
- Azimuth
- Shading
- Surface temperature
- Available area
- Structural condition
- Access difficulty
- Cable-routing distance
The roof section with the highest instantaneous irradiance may not automatically be the best installation area. Safety, structure, orientation, shading and maintenance access must also be considered.
Use Data Logging for Changing Conditions
The UT381PV stores up to 12,800 measurement sets, with intervals from one second to 60 minutes.
Data logging can help monitor:
- Passing-cloud effects
- Moving shadows
- Short-term irradiance changes
- Temperature changes
- Differences between proposed locations
Bluetooth connection to the UNI-T iENV App allows the readings to be reviewed more conveniently.
For a complete shading and energy assessment, longer-term site data or solar-design software may still be required.
Recommended Site-Survey Information
A practical solar site-survey report should include:
- Customer and site details
- Roof or ground layout
- Photographs
- Proposed panel locations
- Irradiance readings
- Inclination measurements
- Azimuth measurements
- Visible shading sources
- Roof condition
- Access route
- Cable route
- Inverter location
- Safety risks
- Additional assessment required
Clear records help the design and installation teams understand the actual site conditions.
What the UT381PV Does Not Replace
The UT381PV provides useful environmental and positioning measurements, but it does not replace:
- Structural roof assessment
- Annual solar-yield simulation
- Detailed shading analysis
- Electrical-load analysis
- Cable-sizing calculations
- Lightning-protection design
- Earthing assessment
- Authority or utility requirements
- Professional engineering approval
The instrument should be used as part of a broader solar site-survey process.
For assistance selecting the UNI-T UT381PV for pre-installation solar site surveys 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
