diff --git a/simulation/costs.py b/simulation/costs.py
index 22e57a1..c4d1c4c 100644
--- a/simulation/costs.py
+++ b/simulation/costs.py
@@ -312,7 +312,7 @@ def estimate_boiler_upgrade_scheme_grant(
         return 0
 
     model_population_scale = ENGLAND_WALES_HOUSEHOLD_COUNT_2020 / model.household_count
-    boiler_upgrade_funding_cap_gbp = 450_000_000 / model_population_scale
+    boiler_upgrade_funding_cap_gbp = 237_500_000 / model_population_scale
     if (
         model.boiler_upgrade_scheme_cumulative_spend_gbp
         >= boiler_upgrade_funding_cap_gbp
@@ -345,7 +345,7 @@ def estimate_extended_boiler_upgrade_scheme_grant(
         return 0
 
     model_population_scale = ENGLAND_WALES_HOUSEHOLD_COUNT_2020 / model.household_count
-    boiler_upgrade_funding_cap_gbp = 1_650_000_000 / model_population_scale
+    boiler_upgrade_funding_cap_gbp = 5_400_000_000 / model_population_scale
     if (
         model.boiler_upgrade_scheme_cumulative_spend_gbp
         >= boiler_upgrade_funding_cap_gbp
diff --git a/simulation/tests/test_costs.py b/simulation/tests/test_costs.py
index 0d6e779..39ca7f4 100644
--- a/simulation/tests/test_costs.py
+++ b/simulation/tests/test_costs.py
@@ -227,7 +227,7 @@ def test_boiler_upgrade_scheme_grant_is_zero_when_grant_cap_exceeded(
         model_population_scale = (
             ENGLAND_WALES_HOUSEHOLD_COUNT_2020 / model.household_count
         )
-        boiler_upgrade_scheme_budget_scaled = 450_000_000 / model_population_scale
+        boiler_upgrade_scheme_budget_scaled = 237_500_000 / model_population_scale
 
         model.boiler_upgrade_scheme_cumulative_spend_gbp = (
             boiler_upgrade_scheme_budget_scaled * 0.8
@@ -338,7 +338,7 @@ def test_extended_boiler_upgrade_scheme_grant_is_zero_when_grant_cap_exceeded(
         model_population_scale = (
             ENGLAND_WALES_HOUSEHOLD_COUNT_2020 / model.household_count
         )
-        boiler_upgrade_scheme_budget_scaled = 1_650_000_000 / model_population_scale
+        boiler_upgrade_scheme_budget_scaled = 5_400_000_000 / model_population_scale
 
         model.boiler_upgrade_scheme_cumulative_spend_gbp = (
             boiler_upgrade_scheme_budget_scaled * 0.8