Place the IN-SOL Solar Power Meter on the outside and on the same plane as the glazing and
ensure that you do not shade the sensor.
A day with the sun shining will give more accurate readings. Read the values displayed from the multi-meter or with the integrated IN-SOL solar meter and this corresponds to the watts/m2 that are falling on the glazing.
Now place the IN-SOL Solar Power Meter / Pyranomètre on the inside on the same plane as the glazing with the sensor area facing outwards.
Read the display from the multi-meter or IN-SOL meter and this corresponds to the watts /m2 that are getting through the glazing.
Calculating the Glazing SHGC /g-value
To calculate the SHGC divide the inside power reading by the outside irradiance reading
and this provides the SHGC (Solar Heat Gain Coefficient also known as the g-Value of glazing). If the inside reading is 500w/m2 and the outside reading is 1000w/m2 then the SHGC or g-value is 0.5 which equates to 50% of solar heat
gain is being transmitted through the window. The lower the value the less heat is transmitted through the window. Note:-The highest accuracy can be achieved by carrying out the test a few times to get an average and using direct irradiance rather than diffused or reflected irradiance. The tint of the glazing will also reduce when the SHGC/g-value is reduced.
The IN-SOL PV Calculator app will help establish the heat energy coming through the window when a measurement is taken on the inside only. One can set all the solar PV /Inverter efficiency values that are not relevant for glazing to 100% and the temperature to 20 degrees Celcius.