diff --git a/test/test-basic-properties.js b/test/test-basic-properties.js
index 481e3de..a825ee9 100644
--- a/test/test-basic-properties.js
+++ b/test/test-basic-properties.js
@@ -250,6 +250,19 @@ it('inheritance is considered in type checking', () => {
   assert(el.objectProperty === array, 'property was set');
 });
 
+it('numeric properties deserialize "" (empty) to "NaN"', () => {
+  const el = document.createElement('test-element');
+  el.setAttribute('numeric-property', '0');
+  document.body.append(el);
+  assert(el.numericProperty === 0, '"0" was coerced to 0');
+  el.setAttribute('numeric-property', '');
+  assert(Number.isNaN(el.numericProperty), '"" was coerced to NaN');
+  el.setAttribute('numeric-property', ' ');
+  assert(Number.isNaN(el.numericProperty), '" " was coerced to NaN');
+  el.setAttribute('numeric-property', '      ');
+  assert(Number.isNaN(el.numericProperty), '"      " was coerced to NaN');
+});
+
 it('cannot set to known properties', () => {
   class BadTestElement extends XElement {
     static get properties() {
diff --git a/x-element.js b/x-element.js
index 441ee4b..8a9d215 100644
--- a/x-element.js
+++ b/x-element.js
@@ -852,7 +852,13 @@ export default class XElement extends HTMLElement {
       return value;
     } else {
       // Coerce type as needed.
-      return property.type(value);
+      switch (property.type) {
+        case Number:
+          // Don't try and coerce something like "Number('') >> 0".
+          return value.trim() ? property.type(value) : Number.NaN;
+        default:
+          return property.type(value);
+      }
     }
   }