diff --git a/src/libdramsys/DRAMSys/simulation/Dram.cpp b/src/libdramsys/DRAMSys/simulation/Dram.cpp
index c110ad02..7b4cdeaa 100644
--- a/src/libdramsys/DRAMSys/simulation/Dram.cpp
+++ b/src/libdramsys/DRAMSys/simulation/Dram.cpp
@@ -316,6 +316,7 @@ void Dram::powerWindow()
 
         currentEnergy = this->DRAMPower->getTotalEnergy(clkCycles);
         windowEnergy = currentEnergy - previousEnergy;
+        previousEnergy = currentEnergy;
 
         // During operation the energy should never be zero since the device is always consuming
         assert(!(windowEnergy < 1e-15));