diff --git a/src/pluginbattery/templates/index.html b/src/pluginbattery/templates/index.html
index c477e96..63ce731 100644
--- a/src/pluginbattery/templates/index.html
+++ b/src/pluginbattery/templates/index.html
@@ -4,7 +4,7 @@
 <meta charset="utf-8">
 <meta name="viewport" content="width=device-width, initial-scale=1">
 <title>Honest battery payback — vs thuisbatterijgids.nl</title>
-<link rel="stylesheet" href="{{ url_for('static', filename='style.css') }}?v=11">
+<link rel="stylesheet" href="{{ url_for('static', filename='style.css') }}?v=12">
 </head>
 <body>
 
@@ -31,7 +31,9 @@
 
       <label>PV system (kWp)
         <input type="number" name="pv_kwp" min="0" max="100" step="any" value="{{ defaults.pv_kwp }}">
-        <small>0 = no PV. Yield assumed 875 kWh/kWp/yr (NL norm).</small>
+        <small>0 = none (or already netted in your P1 data). Synthesizes
+        additional PV at 875 kWh/kWp/yr — leave at 0 unless you want to
+        model extra PV beyond what's in the load signal.</small>
       </label>
 
       <fieldset>
@@ -150,6 +152,6 @@
   </p>
 </footer>
 
-<script src="{{ url_for('static', filename='app.js') }}?v=11"></script>
+<script src="{{ url_for('static', filename='app.js') }}?v=12"></script>
 </body>
 </html>
diff --git a/src/pluginbattery/web.py b/src/pluginbattery/web.py
index 146418c..f6d1896 100644
--- a/src/pluginbattery/web.py
+++ b/src/pluginbattery/web.py
@@ -308,9 +308,12 @@ def compute_leaderboard(
 app = Flask(__name__)
 
 DEFAULTS = dict(
-    demand_kwh=4000.0, retail=0.25, pv_kwp=3.0, pv_yield=875.0,
+    # Dad's actual: 2350 kWh/yr net (P1 data already nets his 3 kWp PV
+    # exports), retail €0.25, terugleveringskosten −€0.106/kWh.
+    # Set pv_kwp = 0 because the 3 kWp solar is already inside the P1.
+    demand_kwh=2350.0, retail=0.25, pv_kwp=0.0, pv_yield=875.0,
     fixed_rate=False, saldering=False, eta=0.88, inflation=0.03,
-    export_rate=None,
+    export_rate=-0.106,
 )
 
 
