diff --git a/esphome/components/sensor/filter.h b/esphome/components/sensor/filter.h
index a3bd7b6b511..be63f99faee 100644
--- a/esphome/components/sensor/filter.h
+++ b/esphome/components/sensor/filter.h
@@ -506,11 +506,7 @@ optional<float> calibrate_polynomial_compute(const float *coefficients, size_t c
 template<size_t N> class CalibratePolynomialFilter : public Filter {
  public:
   explicit CalibratePolynomialFilter(std::initializer_list<float> coefficients) {
-    ESPHOME_DEBUG_ASSERT(coefficients.size() == N);
-    size_t i = 0;
-    for (float c : coefficients) {
-      this->coefficients_[i++] = c;
-    }
+    init_array_from(this->coefficients_, coefficients);
   }
   optional<float> new_value(float value) override {
     return calibrate_polynomial_compute(this->coefficients_.data(), N, value);
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 82c6b3833ce..51feaa57c50 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -497,6 +497,21 @@ template<typename T, size_t MAX_CAPACITY = std::numeric_limits<uint16_t>::max()>
   index_type capacity_{0};
 };
 
+/// Initialize a std::array from an initializer_list. Uses memcpy for trivially copyable types (optimal codegen),
+/// falls back to element-wise copy for non-trivially copyable types (e.g. TemplatableValue).
+/// N is set by code generation; ESPHOME_DEBUG_ASSERT catches mismatches in debug/integration tests.
+template<typename T, size_t N> inline void init_array_from(std::array<T, N> &dest, std::initializer_list<T> src) {
+  ESPHOME_DEBUG_ASSERT(src.size() == N);
+  if constexpr (std::is_trivially_copyable_v<T>) {
+    __builtin_memcpy(dest.data(), src.begin(), N * sizeof(T));
+  } else {
+    size_t i = 0;
+    for (const auto &v : src) {
+      dest[i++] = v;
+    }
+  }
+}
+
 /// Fixed-capacity vector - allocates once at runtime, never reallocates
 /// This avoids std::vector template overhead (_M_realloc_insert, _M_default_append)
 /// when size is known at initialization but not at compile time