diff -r c92651a54969 -r 468ec0d96cce thermferm/simulator.c
--- a/thermferm/simulator.c	Sat May 16 17:39:30 2015 +0200
+++ b/thermferm/simulator.c	Sun May 17 19:34:55 2015 +0200
@@ -49,6 +49,13 @@
     if (debug)
 	fprintf(stdout, "Thread my_simulator_loop started\n");
 
+    for (simulator = Config.simulators; simulator; simulator = simulator->next) {
+	/*
+	 * Heater and cooler have the air temperature
+	 */
+	simulator->s_heat_temp = simulator->s_cool_temp = simulator->room_temperature;
+    }
+
     for (;;) {
 	for (simulator = Config.simulators; simulator; simulator = simulator->next) {
 	    if (my_shutdown)
@@ -81,7 +88,11 @@
 	    	 * Finally, calculate the new air and plate temperature.
 	    	 */
 		if (SIMheating) {
-		    simulator->air_temperature += 0.01;
+		    if (simulator->s_heat_temp < simulator->heater_temp)
+			simulator->s_heat_temp += 0.05;
+		} else {
+		    if (simulator->s_heat_temp > simulator->room_temperature)
+			simulator->s_heat_temp -= 0.05;
 		}
 
 	    	/* 
@@ -90,9 +101,16 @@
 	    	 * Finsally, calculate the new air and plate temperature.
 	    	 */
 		if (SIMcooling) {
-		    simulator->air_temperature -= 0.01;
+		    if (simulator->s_cool_temp > simulator->cooler_temp)
+			simulator->s_cool_temp -= 0.05;
+		} else {
+		    if (simulator->s_cool_temp < simulator->room_temperature)
+			simulator->s_cool_temp += 0.05;
 		}
 
+		simulator->air_temperature += ((simulator->s_heat_temp - simulator->air_temperature) / 50.0);
+		simulator->air_temperature -= ((simulator->air_temperature - simulator->s_cool_temp) / 50.0);
+
 	    	/*
 	    	 * Calculate the extra beer temperatur rise to simulate the heat produced by the
 	    	 * fermentation process. Peak about one day after start and slowly decrease after
@@ -107,6 +125,12 @@
 	    	/*
 	    	 * Calculate final temperature of the beer and the air.
 	    	 */
+		// Cheap trick, just follow slowly the air temp.
+		simulator->beer_temperature += ((simulator->air_temperature - simulator->beer_temperature) / 200.0);
+
+		syslog(LOG_NOTICE, "air=%.3f beer=%.3f heater=%.3f cooler=%.3f", simulator->air_temperature, simulator->beer_temperature,
+				simulator->s_heat_temp, simulator->s_cool_temp);
+
 		if (debug)
 		    fprintf(stdout, "sqm_room_air=%f air=%f air_heat_transfer=%f air_change=%f  sqm_beer_air=%f beer=%f beer_heat_transfer=%f\n",
 			sqm_room_air, simulator->air_temperature, air_heat_transfer, air_change,