TENMARS TM206 Solar Irradiance Meter This .... + / -3 BTU/ ( ft2xh) ] or + / - 5% whichever is greater in sunlight; Additional temperature included error + / - 0.38 W/ m2 / Â º C [ + / -0.12 BTU/ ....
Specification Operating Temperature & RH : 0~ 40 .... 10W/ m2 [  ± 3BTU( ft2* h) ] or  ± 5% whichever is greater in sunlight. Additional temperature induced error  ± 0.38W/ m2/  ° C Over Range....