diff --git a/README.md b/README.md
index c5b6a44..c5749cb 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,11 @@ $ ./bumblebee-status -l themes
 $ ./bumblebee-status -l modules
 ```
 
+To change the update interval, use:
+```
+$ ./bumblebee-status -m <list of modules> -p interval=<interval in seconds>
+```
+
 As a simple example, this is what my i3 configuration looks like:
 
 ```
diff --git a/bumblebee/engine.py b/bumblebee/engine.py
index 67234fe..c0ea9cc 100644
--- a/bumblebee/engine.py
+++ b/bumblebee/engine.py
@@ -158,7 +158,7 @@ class Engine(object):
             self._output.flush()
             self._output.end()
             if self.running():
-                self.input.wait(self._config.get("interval", 1))
+                self.input.wait(float(self._config.get("interval", 1)))
 
         self._output.stop()
         self.input.stop()