diff --git a/include/hepa-uv/firmware/hepa_control_hardware.hpp b/include/hepa-uv/firmware/hepa_control_hardware.hpp
index 6495ac505..a3888d13e 100644
--- a/include/hepa-uv/firmware/hepa_control_hardware.hpp
+++ b/include/hepa-uv/firmware/hepa_control_hardware.hpp
@@ -14,13 +14,13 @@ class HepaControlHardware : public hepa_control::HepaControlInterface {
     ~HepaControlHardware() final = default;
 
     void set_hepa_fan_speed(uint32_t duty_cycle) final;
-    uint16_t get_hepa_fan_rpm() final;
+    auto get_hepa_fan_rpm() -> uint16_t final;
     void reset_hepa_fan_rpm() final;
     void hepa_fan_rpm_irq(uint16_t rpm) final;
-    bool enable_tachometer(bool enable) final;
+    auto enable_tachometer(bool enable) -> bool final;
 
   private:
     uint16_t hepa_fan_rpm = 0;
 };
 
-}  // namespace hepa_control_hardware
\ No newline at end of file
+}  // namespace hepa_control_hardware