diff --git a/system/roles/laptop/power/default.nix b/system/roles/laptop/power/default.nix
index 673e56a..7f96826 100644
--- a/system/roles/laptop/power/default.nix
+++ b/system/roles/laptop/power/default.nix
@@ -12,6 +12,7 @@ in {
     ./power-profiles-daemon
     ./upower.nix
     ./acpi.nix
+    ./systemd.nix
   ];
 
   config = mkIf (builtins.elem deviceType acceptedTypes) {
diff --git a/system/roles/laptop/power/systemd.nix b/system/roles/laptop/power/systemd.nix
new file mode 100644
index 0000000..510eae2
--- /dev/null
+++ b/system/roles/laptop/power/systemd.nix
@@ -0,0 +1,7 @@
+{
+  # /etc/systemd/sleep.conf
+  systemd.sleep.extraConfig = ''
+    # Configure `systemctl suspend-then-sleep` to enter hibernation after 3 hours of sleep.
+    HibernateDelaySec=10800
+  '';
+}