Home Energy Monitoring via flashing LED on Meter

Your TSOP4136 sensor is for a signal of 36kHz. It is used for remote controls.
So it will work for a certain IR wave lenght, which is coded at a frequency of 36kHz.

Is the led a normal red led ? then it is certainly not IR, and it is not coded with 36kHz.
You need a phototransistor or photodiode.