diff --git a/include/xlnt/worksheet/sheet_format_properties.hpp b/include/xlnt/worksheet/sheet_format_properties.hpp
index c71eefbe..52e4ceb1 100644
--- a/include/xlnt/worksheet/sheet_format_properties.hpp
+++ b/include/xlnt/worksheet/sheet_format_properties.hpp
@@ -40,9 +40,9 @@ public:
     optional<double> base_col_width;
 
     /// <summary>
-    /// The default row height
+    /// The default row height is required
     /// </summary>
-    optional<double> default_row_height;
+    double default_row_height = 15.0;
 
     /// <summary>
     /// The default column width
diff --git a/source/detail/serialization/xlsx_producer.cpp b/source/detail/serialization/xlsx_producer.cpp
index ec0d890e..212b0d89 100644
--- a/source/detail/serialization/xlsx_producer.cpp
+++ b/source/detail/serialization/xlsx_producer.cpp
@@ -2353,11 +2353,9 @@ void xlsx_producer::write_worksheet(const relationship &rel)
         write_attribute("defaultColWidth",
             format_properties.default_column_width.get());
     }
-    if (format_properties.default_row_height.is_set())
-    {
-        write_attribute("defaultRowHeight",
-            format_properties.default_row_height.get());
-    }
+
+    write_attribute("defaultRowHeight",
+            format_properties.default_row_height);
 
     if (format_properties.dy_descent.is_set())
     {