diff --git a/recommendations/tests/test_costs.py b/recommendations/tests/test_costs.py
index ab822322..1f5b300c 100644
--- a/recommendations/tests/test_costs.py
+++ b/recommendations/tests/test_costs.py
@@ -1,6 +1,7 @@
 from recommendations.Costs import Costs
 from unittest.mock import Mock
 import datetime
+import pytest
 
 
 class TestCosts:
@@ -499,3 +500,48 @@ class TestCosts:
                                            'labour_hours': 24.79, 'labour_days': 1.549375, 'labour_cost': 186.9032}
 
         assert costs.labour_adjustment_factor == 0.88
+
+    # Mock property instance for regional tests
+    @pytest.fixture(params=[
+        ("Northamptonshire", "East Midlands", 7927.44),
+        ("Greater London Authority", "Inner London", 10475.0),
+        ("Adur", "South East England", 8333.32),
+        ("Bournemouth", "South West England", 8452),
+        ("Basildon", "East of England", 7895.44),
+        ("Birmingham", "West Midlands", 7706.2),
+        ("County Durham", "North East England", 8113.96),
+        ("Allerdale", "North West England", 6481.68),
+        ("York", "Yorkshire and the Humber", 8243.6),
+        ("Cardiff", "Wales", 7595.32),
+        ("Glasgow City", "Scotland", 7871.88),
+        ("Belfast", "Northern Ireland", 8504.36)
+    ])
+    def mock_property_with_region(self, request):
+        county, region, expected_cost = request.param
+        mock_property = Mock()
+        mock_property.data = {"county": county}
+        return mock_property, region, expected_cost
+
+    # Test for different wattages
+    @pytest.mark.parametrize("wattage, expected_cost", [
+        (3000, 5945.58),
+        (4000, 7927.44),
+        (5000, 9909.3),
+        (6000, 11891.16),
+    ])
+    def test_solar_pv_different_wattages(self, wattage, expected_cost):
+        mock_property = Mock()
+        mock_property.data = {"county": "Mansfield"}
+        costs = Costs(mock_property)
+        result = costs.solar_pv(wattage)
+        assert result['total'] == pytest.approx(expected_cost, rel=0.01)
+
+    def test_solar_pv_regional_variation(self, mock_property_with_region):
+        # Test for regional cost variations
+        property_instance, expected_region, expected_cost = mock_property_with_region
+        costs = Costs(property_instance)
+
+        assert costs.region == expected_region
+
+        result = costs.solar_pv(4000)  # Testing with a fixed wattage of 4000
+        assert result['total'] == pytest.approx(expected_cost, rel=0.01)