diff --git a/DRAMSys/dram.vp.system.pro b/DRAMSys/dram.vp.system.pro
index 37b7397b..5a29d611 100644
--- a/DRAMSys/dram.vp.system.pro
+++ b/DRAMSys/dram.vp.system.pro
@@ -1,6 +1,10 @@
 TEMPLATE = subdirs
 
 thermalsim = $$(THERMALSIM)
+isEmpty(thermalsim) {
+    thermalsim = false
+}
+
 $$eval(thermalsim) {
     message(Thermal Simulation Feature Enabled)
 
diff --git a/DRAMSys/simulator/simulator.pro b/DRAMSys/simulator/simulator.pro
index 9f18dd15..3c908dbe 100644
--- a/DRAMSys/simulator/simulator.pro
+++ b/DRAMSys/simulator/simulator.pro
@@ -135,6 +135,10 @@ HEADERS += \
     src/error/errormodel.h
 
 thermalsim = $$(THERMALSIM)
+isEmpty(thermalsim) {
+    thermalsim = false
+}
+
 $$eval(thermalsim) {
     message(Thermal Simulation Feature Enabled)