diff --git a/README.adoc b/README.adoc
index 638442e..aea3353 100644
--- a/README.adoc
+++ b/README.adoc
@@ -440,7 +440,7 @@ fan_policy_cooldown: 900
 # voc index, 0 to disable, filter if any sensor meets this threshold
 fan_policy_voc_passive_max: 125
 # voc index, 0 to disable, filter if the intake exceeds exhaust by at least this much
-fan_policy_voc_improve_min: 5
+fan_policy_voc_improve_min: 25
 
 # Fan Policy - Thermal Limit
 # Controls how/when the fan power is throttled down if the temperature is too high.
diff --git a/src/utility/fan_policy.hpp b/src/utility/fan_policy.hpp
index 606c23b..aefe231 100644
--- a/src/utility/fan_policy.hpp
+++ b/src/utility/fan_policy.hpp
@@ -13,7 +13,7 @@ struct FanPolicyEnvironmental {
     // How long to keep spinning after `should_filter` returns `false`
     BLE::TimeSecond16 cooldown = 60 * 15;
     VOCIndex voc_passive_max = 125;  // <= max(intake, exhaust)  -> filthy in here; get scrubbin'
-    VOCIndex voc_improve_min = 5;    // <= (intake - exhaust)    -> things are improving, keep filtering
+    VOCIndex voc_improve_min = 25;   // <= (intake - exhaust)    -> things are improving, keep filtering
 
     struct Instance {
         FanPolicyEnvironmental const& params;  // NOLINT(cppcoreguidelines-avoid-const-or-ref-data-members)