diff --git a/src/components/ha-attributes.js b/src/components/ha-attributes.js
index 9e86391b0e..b62986cdf6 100644
--- a/src/components/ha-attributes.js
+++ b/src/components/ha-attributes.js
@@ -2,7 +2,7 @@ import '@polymer/iron-flex-layout/iron-flex-layout-classes.js';
 import { html } from '@polymer/polymer/lib/utils/html-tag.js';
 import { PolymerElement } from '@polymer/polymer/polymer-element.js';
 
-import '../util/hass-attributes-util.js';
+import hassAttributeUtil from '../util/hass-attributes-util.js';
 
 class HaAttributes extends PolymerElement {
   static get template() {
@@ -47,7 +47,7 @@ class HaAttributes extends PolymerElement {
   }
 
   computeFiltersArray(extraFilters) {
-    return Object.keys(window.hassAttributeUtil.LOGIC_STATE_ATTRIBUTES).concat(extraFilters ? extraFilters.split(',') : []);
+    return Object.keys(hassAttributeUtil.LOGIC_STATE_ATTRIBUTES).concat(extraFilters ? extraFilters.split(',') : []);
   }
 
   computeDisplayAttributes(stateObj, filtersArray) {
diff --git a/src/panels/config/customize/ha-customize-attribute.js b/src/panels/config/customize/ha-customize-attribute.js
index 3fdd516473..0726e2eb54 100644
--- a/src/panels/config/customize/ha-customize-attribute.js
+++ b/src/panels/config/customize/ha-customize-attribute.js
@@ -2,7 +2,7 @@ import '@polymer/paper-icon-button/paper-icon-button.js';
 import { html } from '@polymer/polymer/lib/utils/html-tag.js';
 import { PolymerElement } from '@polymer/polymer/polymer-element.js';
 
-import '../../../util/hass-attributes-util.js';
+import hassAttributeUtil from '../../../util/hass-attributes-util.js';
 import '../ha-form-style.js';
 import './types/ha-customize-array.js';
 import './types/ha-customize-boolean.js';
@@ -56,7 +56,7 @@ class HaCustomizeAttribute extends PolymerElement {
 
   itemObserver(item) {
     const wrapper = this.$.wrapper;
-    const tag = window.hassAttributeUtil.TYPE_TO_TAG[item.type].toUpperCase();
+    const tag = hassAttributeUtil.TYPE_TO_TAG[item.type].toUpperCase();
     let child;
     if (wrapper.lastChild && wrapper.lastChild.tagName === tag) {
       child = wrapper.lastChild;
diff --git a/src/panels/config/customize/ha-form-customize.js b/src/panels/config/customize/ha-form-customize.js
index 0869ec5fa0..5f6ed7c3d4 100644
--- a/src/panels/config/customize/ha-form-customize.js
+++ b/src/panels/config/customize/ha-form-customize.js
@@ -4,7 +4,7 @@ import '@polymer/paper-listbox/paper-listbox.js';
 import { html } from '@polymer/polymer/lib/utils/html-tag.js';
 import { PolymerElement } from '@polymer/polymer/polymer-element.js';
 
-import '../../../util/hass-attributes-util.js';
+import hassAttributeUtil from '../../../util/hass-attributes-util.js';
 import './ha-form-customize-attributes.js';
 
 import computeStateDomain from '../../../common/entity/compute_state_domain';
@@ -152,8 +152,8 @@ class HaFormCustomize extends PolymerElement {
   }
 
   _computeSingleAttribute(key, value, secondary) {
-    const config = window.hassAttributeUtil.LOGIC_STATE_ATTRIBUTES[key]
-        || { type: window.hassAttributeUtil.UNKNOWN_TYPE };
+    const config = hassAttributeUtil.LOGIC_STATE_ATTRIBUTES[key]
+        || { type: hassAttributeUtil.UNKNOWN_TYPE };
     return this._initOpenObject(key, config.type === 'json' ? JSON.stringify(value) : value, secondary, config);
   }
 
@@ -196,9 +196,9 @@ class HaFormCustomize extends PolymerElement {
 
   getNewAttributesOptions(localAttributes, globalAttributes, existingAttributes, newAttributes) {
     const knownKeys =
-        Object.keys(window.hassAttributeUtil.LOGIC_STATE_ATTRIBUTES)
+        Object.keys(hassAttributeUtil.LOGIC_STATE_ATTRIBUTES)
           .filter((key) => {
-            const conf = window.hassAttributeUtil.LOGIC_STATE_ATTRIBUTES[key];
+            const conf = hassAttributeUtil.LOGIC_STATE_ATTRIBUTES[key];
             return conf && (!conf.domains || !this.entity ||
                               conf.domains.includes(computeStateDomain(this.entity)));
           })
@@ -214,7 +214,7 @@ class HaFormCustomize extends PolymerElement {
     const option = this.newAttributesOptions[selected];
     if (selected === this.newAttributesOptions.length - 1) {
       // The "Other" option.
-      const attr = this._initOpenObject('', '', false /* secondary */, { type: window.hassAttributeUtil.ADD_TYPE });
+      const attr = this._initOpenObject('', '', false /* secondary */, { type: hassAttributeUtil.ADD_TYPE });
       this.push('newAttributes', attr);
       this.selectedNewAttribute = -1;
       return;
diff --git a/src/util/hass-attributes-util.js b/src/util/hass-attributes-util.js
index de3ffcd016..75945a37b9 100644
--- a/src/util/hass-attributes-util.js
+++ b/src/util/hass-attributes-util.js
@@ -1,6 +1,6 @@
-window.hassAttributeUtil = window.hassAttributeUtil || {};
+const hassAttributeUtil = {};
 
-window.hassAttributeUtil.DOMAIN_DEVICE_CLASS = {
+hassAttributeUtil.DOMAIN_DEVICE_CLASS = {
   binary_sensor: [
     'battery',
     'cold',
@@ -35,10 +35,10 @@ window.hassAttributeUtil.DOMAIN_DEVICE_CLASS = {
   ],
 };
 
-window.hassAttributeUtil.UNKNOWN_TYPE = 'json';
-window.hassAttributeUtil.ADD_TYPE = 'key-value';
+hassAttributeUtil.UNKNOWN_TYPE = 'json';
+hassAttributeUtil.ADD_TYPE = 'key-value';
 
-window.hassAttributeUtil.TYPE_TO_TAG = {
+hassAttributeUtil.TYPE_TO_TAG = {
   string: 'ha-customize-string',
   json: 'ha-customize-string',
   icon: 'ha-customize-icon',
@@ -51,8 +51,8 @@ window.hassAttributeUtil.TYPE_TO_TAG = {
 // 1) Any key of this object won't be shown in more-info window.
 // 2) Any key which has value other than undefined will appear in customization
 //    config according to its value.
-window.hassAttributeUtil.LOGIC_STATE_ATTRIBUTES =
-  window.hassAttributeUtil.LOGIC_STATE_ATTRIBUTES || {
+hassAttributeUtil.LOGIC_STATE_ATTRIBUTES =
+  hassAttributeUtil.LOGIC_STATE_ATTRIBUTES || {
     entity_picture: undefined,
     friendly_name: { type: 'string', description: 'Name' },
     icon: { type: 'icon' },
@@ -74,7 +74,7 @@ window.hassAttributeUtil.LOGIC_STATE_ATTRIBUTES =
     custom_ui_state_card: { type: 'string' },
     device_class: {
       type: 'array',
-      options: window.hassAttributeUtil.DOMAIN_DEVICE_CLASS,
+      options: hassAttributeUtil.DOMAIN_DEVICE_CLASS,
       description: 'Device class',
       domains: ['binary_sensor', 'cover', 'sensor']
     },
@@ -89,3 +89,5 @@ window.hassAttributeUtil.LOGIC_STATE_ATTRIBUTES =
     },
     unit_of_measurement: { type: 'string' },
   };
+
+export default hassAttributeUtil;