diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 316690b..b4ef87c 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -62,7 +62,16 @@ import {
 } from "lucide-react";
 
 const queryClient = new QueryClient({
-	defaultOptions: { queries: { retry: 1, refetchOnWindowFocus: false } },
+	defaultOptions: {
+		queries: {
+			retry: 1,
+			refetchOnWindowFocus: false,
+			// Pause interval-based refetches (widgets ~30s, queue status 5s,
+			// media build progress 1s) when the tab is hidden. Saves battery on
+			// mobile (D8 follow-up). Build progress polls resume on return.
+			refetchIntervalInBackground: false,
+		},
+	},
 });
 
 function useDarkMode() {
diff --git a/frontend/src/hooks/useMedia.ts b/frontend/src/hooks/useMedia.ts
index bd7b273..2b89d7a 100644
--- a/frontend/src/hooks/useMedia.ts
+++ b/frontend/src/hooks/useMedia.ts
@@ -14,7 +14,10 @@ export function useMediaStatus(jellyfinServiceId?: string) {
 		staleTime: 5_000,
 		refetchInterval: (query) =>
 			query.state.data?.build_running ? 1000 : false,
-		refetchIntervalInBackground: true,
+		// Inherit the default refetchIntervalInBackground: false — pause the
+		// 1s build-progress poll when the tab is hidden. The build keeps
+		// running server-side; the poll resumes and catches up on return.
+		// Battery-friendly (D8 follow-up).
 	});
 }