# W/M2 conversion to PAR?



## Bunsen Honeydew (Feb 21, 2017)

easttech said:


> Hello,
> 
> I was given a meter which is used in the solar industry and provides light measurements in units of W/M2. I have tried searching and doing a conversion but have come up empty. Can anyone help. It was free so I am hoping it can be used.
> 
> Thank you.


A solar meter is going to give you the total light (similar to lumens), whereas PAR is a smaller part of the spectrum, so any conversion would be fairly rough. That being said, you can usually do a rough approximation of PAR from lumens. Maybe try finding the relationship between W/m2 and lumens to get there?


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## jeffkrol (Jun 5, 2013)

easttech said:


> Hello,
> 
> I was given a meter which is used in the solar industry and provides light measurements in units of W/M2. I have tried searching and doing a conversion but have come up empty. Can anyone help. It was free so I am hoping it can be used.
> 
> Thank you.





> To convert units, multiply the measurement from the sensor, in units of µmol m-2 s-1, by 0.327 J µmol-1. This converts the UV measurement to units of J m-2 s-1, which is W m-2.


Use this backwards.. divide meter reading by .327....
https://www.apogeeinstruments.com/conversion-ppf-to-watts/

Test it in full daylight..At noon in CT. should be about 2000 PPFD (PAR) on a clear day..









won't be accurate but we will know if it is in the ballpark..


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## easttech (Mar 16, 2013)

Let me get a battery for it and give it a try.

Thank you


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## jeffkrol (Jun 5, 2013)

fun calculator..
https://www2.pvlighthouse.com.au/ca...rum calculator/solar spectrum calculator.aspx


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