diff --git a/src/app/db/schema/property.ts b/src/app/db/schema/property.ts
index 132721bc..51f4afc5 100644
--- a/src/app/db/schema/property.ts
+++ b/src/app/db/schema/property.ts
@@ -748,7 +748,7 @@ export const epcWindow = pgTable(
 
     // Transmission details (inlined)
     transmissionUValue:               real("transmission_u_value"),
-    transmissionDataSource:           integer("transmission_data_source"),
+    transmissionDataSource:           text("transmission_data_source"),
     transmissionSolarTransmittance:   real("transmission_solar_transmittance"),
   },
 );