diff --git a/thermostat.go b/thermostat.go
index b9f92c4..62bff2b 100644
--- a/thermostat.go
+++ b/thermostat.go
@@ -83,11 +83,9 @@ func ProcessSensor(sensor Sensor, state State) (State, error) {
 	// Temperature is too high and the cooling switch is still on, do nothing
 	case temp > sensor.HighTemp && state.Cooling:
 		break
-	// Temperature is too high, but duration hasn't been met
-	case temp > sensor.HighTemp:
-		if state.Changed.After(time.Now()) {
-			state.Changed = time.Now()
-		}
+	// Temperature is too high, but duration hasn't been counted
+	case temp > sensor.HighTemp && duration < 0:
+		state.Changed = time.Now()
 	// Temperature is too high and the duration has been long enough, start cooling
 	case temp > sensor.HighTemp && duration > sensor.CoolMinutes:
 		PinSwitch(cpin, true, sensor.CoolInvert)
@@ -101,11 +99,9 @@ func ProcessSensor(sensor Sensor, state State) (State, error) {
 	// Temperature is too low and the heating switch is on, do nothing
 	case temp < sensor.LowTemp && state.Heating:
 		break
-	// Temperature is too low, but duration hasn't been met
-	case temp < sensor.LowTemp:
-		if state.Changed.After(time.Now()) {
-			state.Changed = time.Now()
-		}
+	// Temperature is too low, but duration hasn't been counted
+	case temp < sensor.LowTemp && duration < 0:
+		state.Changed = time.Now()
 	// Temperature is too low and the duration has been long enough, start heating
 	case temp < sensor.LowTemp && duration > sensor.HeatMinutes:
 		PinSwitch(hpin, true, sensor.HeatInvert)