diff --git a/homeassistant/components/opower/coordinator.py b/homeassistant/components/opower/coordinator.py
index d53706b315c302..6d542663cdd2e8 100644
--- a/homeassistant/components/opower/coordinator.py
+++ b/homeassistant/components/opower/coordinator.py
@@ -563,8 +563,17 @@ def _update_with_finer_cost_reads(
                 account, AggregateType.DAY, start, end
             )
         except ApiException as err:
-            _LOGGER.error("Error getting daily cost reads: %s", err)
-            raise
+            _LOGGER.warning(
+                "Error getting daily cost reads, falling back to usage-only: %s",
+                err,
+            )
+            try:
+                daily_cost_reads = await self.api.async_get_cost_reads(
+                    account, AggregateType.DAY, start, end, usage_only=True
+                )
+            except ApiException:
+                _LOGGER.warning("Usage-only daily reads also failed, using monthly")
+                return cost_reads
         _LOGGER.debug("Got %s daily cost reads", len(daily_cost_reads))
         _update_with_finer_cost_reads(cost_reads, daily_cost_reads)
         if account.read_resolution == ReadResolution.DAY:
@@ -581,8 +590,19 @@ def _update_with_finer_cost_reads(
                 account, AggregateType.HOUR, start, end
             )
         except ApiException as err:
-            _LOGGER.error("Error getting hourly cost reads: %s", err)
-            raise
+            _LOGGER.warning(
+                "Error getting hourly cost reads, falling back to usage-only: %s",
+                err,
+            )
+            try:
+                hourly_cost_reads = await self.api.async_get_cost_reads(
+                    account, AggregateType.HOUR, start, end, usage_only=True
+                )
+            except ApiException:
+                _LOGGER.warning(
+                    "Usage-only hourly reads also failed, using coarser reads"
+                )
+                return cost_reads
         _LOGGER.debug("Got %s hourly cost reads", len(hourly_cost_reads))
         _update_with_finer_cost_reads(cost_reads, hourly_cost_reads)
         _LOGGER.debug("Got %s cost reads", len(cost_reads))
diff --git a/tests/components/opower/test_coordinator.py b/tests/components/opower/test_coordinator.py
index 6c6624c35f7638..2012fcd4815f16 100644
--- a/tests/components/opower/test_coordinator.py
+++ b/tests/components/opower/test_coordinator.py
@@ -250,8 +250,6 @@ async def test_coordinator_migration(
         ("async_get_accounts", None),
         ("async_get_forecast", None),
         ("async_get_cost_reads", AggregateType.BILL),
-        ("async_get_cost_reads", AggregateType.DAY),
-        ("async_get_cost_reads", AggregateType.HOUR),
     ],
 )
 async def test_coordinator_api_exceptions(
@@ -290,6 +288,54 @@ async def side_effect(account, agg_type, start, end):
         await coordinator._async_update_data()
 
 
+@pytest.mark.parametrize(
+    "failing_aggregate_type",
+    [AggregateType.DAY, AggregateType.HOUR],
+)
+async def test_coordinator_cost_reads_fallback_on_api_error(
+    recorder_mock: Recorder,
+    hass: HomeAssistant,
+    mock_config_entry: MockConfigEntry,
+    mock_opower_api: AsyncMock,
+    failing_aggregate_type: AggregateType,
+) -> None:
+    """Test that daily/hourly cost read failures fall back to usage-only reads."""
+    coordinator = OpowerCoordinator(hass, mock_config_entry)
+
+    # Use a single ELEC account with HOUR resolution so all read levels are attempted
+    account = mock_opower_api.async_get_accounts.return_value[0]
+    mock_opower_api.async_get_accounts.return_value = [account]
+
+    t1 = dt_util.as_utc(datetime(2023, 1, 1, 0))
+    t2 = dt_util.as_utc(datetime(2023, 1, 2, 0))
+    bill_read = CostRead(
+        start_time=t1, end_time=t2, consumption=10.0, provided_cost=1.0
+    )
+    usage_read = CostRead(
+        start_time=t1, end_time=t2, consumption=10.0, provided_cost=0.0
+    )
+
+    async def side_effect(
+        acc: object,
+        agg_type: AggregateType,
+        start: object,
+        end: object,
+        usage_only: bool = False,
+    ) -> list[CostRead]:
+        if agg_type == failing_aggregate_type and not usage_only:
+            raise ApiException(message="HTTP Error: 500", url="http://example.com")
+        if usage_only:
+            return [usage_read]
+        return [bill_read]
+
+    mock_opower_api.async_get_cost_reads.side_effect = side_effect
+
+    # Should NOT raise — the coordinator should fall back to usage-only reads
+    result = await coordinator._async_update_data()
+    await async_wait_recording_done(hass)
+    assert result is not None
+
+
 async def test_coordinator_updates_with_finer_grained_data(
     recorder_mock: Recorder,
     hass: HomeAssistant,