diff --git a/esphome/components/http_request/http_request.h b/esphome/components/http_request/http_request.h
index 3046c8a749..5402155393 100644
--- a/esphome/components/http_request/http_request.h
+++ b/esphome/components/http_request/http_request.h
@@ -90,16 +90,6 @@ inline bool should_collect_header(const std::vector<std::string> &collect_header
   return false;
 }
 
-/// Lowercase a range of strings into a vector
-template<typename Iter> inline std::vector<std::string> lowercase_headers(Iter begin, Iter end) {
-  std::vector<std::string> result;
-  result.reserve(std::distance(begin, end));
-  for (auto it = begin; it != end; ++it) {
-    result.push_back(str_lower_case(*it));
-  }
-  return result;
-}
-
 /*
  * HTTP Container Read Semantics
  * =============================
@@ -374,15 +364,19 @@ class HttpRequestComponent : public Component {
   std::shared_ptr<HttpContainer> start(const std::string &url, const std::string &method, const std::string &body,
                                        const std::list<Header> &request_headers,
                                        const std::set<std::string> &collect_headers) {
-    return this->perform(url, method, body, request_headers,
-                         lowercase_headers(collect_headers.begin(), collect_headers.end()));
+    return this->start(url, method, body, request_headers,
+                       std::vector<std::string>(collect_headers.begin(), collect_headers.end()));
   }
 
   std::shared_ptr<HttpContainer> start(const std::string &url, const std::string &method, const std::string &body,
                                        const std::list<Header> &request_headers,
                                        const std::vector<std::string> &collect_headers) {
-    return this->perform(url, method, body, request_headers,
-                         lowercase_headers(collect_headers.begin(), collect_headers.end()));
+    std::vector<std::string> lower;
+    lower.reserve(collect_headers.size());
+    for (const auto &h : collect_headers) {
+      lower.push_back(str_lower_case(h));
+    }
+    return this->perform(url, method, body, request_headers, lower);
   }
 
  protected: