diff --git a/config/src/main/java/com/typesafe/config/impl/SimpleConfigObject.java b/config/src/main/java/com/typesafe/config/impl/SimpleConfigObject.java
index fb3ac60d..1977bd1b 100644
--- a/config/src/main/java/com/typesafe/config/impl/SimpleConfigObject.java
+++ b/config/src/main/java/com/typesafe/config/impl/SimpleConfigObject.java
@@ -390,7 +390,9 @@ final class SimpleConfigObject extends AbstractConfigObject implements Serializa
                 if (options.getComments()) {
                     for (String comment : v.origin().comments()) {
                         indent(sb, indent + 1, options);
-                        sb.append("# ");
+                        sb.append("#");
+                        if (!comment.startsWith(" "))
+                            sb.append(' ');
                         sb.append(comment);
                         sb.append("\n");
                     }
diff --git a/config/src/test/scala/com/typesafe/config/impl/ConfigTest.scala b/config/src/test/scala/com/typesafe/config/impl/ConfigTest.scala
index 27235172..aa11d41d 100644
--- a/config/src/test/scala/com/typesafe/config/impl/ConfigTest.scala
+++ b/config/src/test/scala/com/typesafe/config/impl/ConfigTest.scala
@@ -1059,6 +1059,15 @@ class ConfigTest extends TestUtils {
                             throw e
                     }
                 }
+                // rendering repeatedly should not make the file different (e.g. shouldn't make it longer)
+                // unless the debug comments are in there
+                if (!renderOptions.getOriginComments()) {
+                    val renderedAgain = resolvedParsed.root.render(renderOptions)
+                    // TODO the strings should be THE SAME not just the same length,
+                    // but there's a bug right now that sometimes object keys seem to
+                    // be re-ordered. Need to fix.
+                    assertEquals("render changed, resolved options=" + renderOptions, resolvedRender.length, renderedAgain.length)
+                }
             }
         }
     }