diff --git a/src/renderer.js b/src/renderer.js
index faffc7ee..af99bc08 100644
--- a/src/renderer.js
+++ b/src/renderer.js
@@ -1,11 +1,11 @@
 
-var Renderer = (function RendererClosure() {
+let Renderer = (function RendererClosure() {
 
-  var rendererFn = false;
+  let rendererFn = false;
 
   if (HeatmapConfig['defaultRenderer'] === 'canvas2d') {
     rendererFn = Canvas2dRenderer;
   }
 
   return rendererFn;
-})();
\ No newline at end of file
+})();