Calibrating the sky illuminance

hello all,

Is there anyway to calibrate the sky illuminance from epw file with the correct measurement that I have? how can I do it?



If you have both “Direct Normal Illuminance” and “Diffuse Horizontal Illuminance” measurements, you can create a high-accuracy calibrated sky by using the “Honeybee_Generate Custom Sky” component.

If you only have a Global Horizontal Illuminance value, you can create a uniform sky by using the “Honeybee_Generate Sky With Certain Illuminance level” component. However, this is going to be very inaccurate unless the values that you have recorded are for an overcast cloudy day.


thank you very much chris, I’ll try this.


Chris said it all. Just a warning that if you’re creating the sky for a non-cloudy day then using the second method is not recommended. You can use watch the sky component to check the illuminance value under the generated sky. A good place to start is probably the weather data around the time that you have done the measurement:

If you have an HDR image of the sky there are more advanced solutions that you can find on the web. (433 KB)

thanks alot mostafa!