Split up atmos speedup from heat scaling (#22372)

Content.Shared/CCVar/CCVars.cs

@@ -1046,12 +1046,19 @@ namespace Content.Shared.CCVar
 
         /// <summary>
         ///     Scale factor for how fast things happen in our atmosphere
-        ///     simulation compared to real life. 1x means that a room takes as
-        ///     long to heat up in game as real life. Players typically expect
-        ///     things to happen faster in-game.
+        ///     simulation compared to real life. 1x means pumps run at 1x
+        ///     speed. Players typically expect things to happen faster
+        ///     in-game.
         /// </summary>
         public static readonly CVarDef<float> AtmosSpeedup =
-            CVarDef.Create("atmos.speedup", 64f, CVar.SERVERONLY);
+            CVarDef.Create("atmos.speedup", 8f, CVar.SERVERONLY);
+
+        /// <summary>
+        ///     Like atmos.speedup, but only for gas and reaction heat values. 64x means
+        ///     gases heat up and cool down 64x faster than real life.
+        /// </summary>
+        public static readonly CVarDef<float> AtmosHeatScale =
+            CVarDef.Create("atmos.heat_scale", 64f, CVar.SERVERONLY);
 
         /*
          * MIDI instruments