diff --git a/SimDataFormats/CaloAnalysis/interface/CaloParticle.h b/SimDataFormats/CaloAnalysis/interface/CaloParticle.h
index 2549634143279..4fd454c72f7e6 100644
--- a/SimDataFormats/CaloAnalysis/interface/CaloParticle.h
+++ b/SimDataFormats/CaloAnalysis/interface/CaloParticle.h
@@ -184,14 +184,17 @@ class CaloParticle {
   float simEnergy() const { return simhit_energy_; }
 
   /** @brief add simhit's energy to cluster */
-  void addSimHit(const PCaloHit &hit) { simhit_energy_ += hit.energy(); }
+  void addSimHit(const PCaloHit &hit) {
+    simhit_energy_ += hit.energy();
+    ++nsimhits_;
+  }
 
 private:
-  uint64_t nsimhits_;
+  uint64_t nsimhits_{0};
   EncodedEventId event_;
 
-  uint32_t particleId_;
-  float simhit_energy_;
+  uint32_t particleId_{0};
+  float simhit_energy_{0.f};
   std::vector<uint32_t> hits_;
   std::vector<float> fractions_;
 
diff --git a/SimDataFormats/CaloAnalysis/interface/SimCluster.h b/SimDataFormats/CaloAnalysis/interface/SimCluster.h
index 30b75545cc0dd..f9042c4c702df 100644
--- a/SimDataFormats/CaloAnalysis/interface/SimCluster.h
+++ b/SimDataFormats/CaloAnalysis/interface/SimCluster.h
@@ -213,14 +213,17 @@ class SimCluster {
   float simEnergy() const { return simhit_energy_; }
 
   /** @brief add simhit's energy to cluster */
-  void addSimHit(const PCaloHit &hit) { simhit_energy_ += hit.energy(); }
+  void addSimHit(const PCaloHit &hit) {
+    simhit_energy_ += hit.energy();
+    ++nsimhits_;
+  }
 
 private:
-  uint64_t nsimhits_;
+  uint64_t nsimhits_{0};
   EncodedEventId event_;
 
-  uint32_t particleId_;
-  float simhit_energy_;
+  uint32_t particleId_{0};
+  float simhit_energy_{0.f};
   std::vector<uint32_t> hits_;
   std::vector<float> fractions_;
   std::vector<float> energies_;