diff --git a/src/components/ha-climate-state.js b/src/components/ha-climate-state.js
deleted file mode 100644
index eb961cce4c..0000000000
--- a/src/components/ha-climate-state.js
+++ /dev/null
@@ -1,131 +0,0 @@
-import { html } from "@polymer/polymer/lib/utils/html-tag";
-/* eslint-plugin-disable lit */
-import { PolymerElement } from "@polymer/polymer/polymer-element";
-import { CLIMATE_PRESET_NONE } from "../data/climate";
-import LocalizeMixin from "../mixins/localize-mixin";
-
-/*
- * @appliesMixin LocalizeMixin
- */
-class HaClimateState extends LocalizeMixin(PolymerElement) {
-  static get template() {
-    return html`
-      <style>
-        :host {
-          display: flex;
-          flex-direction: column;
-          justify-content: center;
-          white-space: nowrap;
-        }
-
-        .target {
-          color: var(--primary-text-color);
-        }
-
-        .current {
-          color: var(--secondary-text-color);
-        }
-
-        .state-label {
-          font-weight: bold;
-          text-transform: capitalize;
-        }
-
-        .unit {
-          display: inline-block;
-          direction: ltr;
-        }
-      </style>
-
-      <div class="target">
-        <template is="dom-if" if="[[_hasKnownState(stateObj.state)]]">
-          <span class="state-label">
-            [[_localizeState(localize, stateObj)]]
-            <template is="dom-if" if="[[_renderPreset(stateObj.attributes)]]">
-              - [[_localizePreset(localize, stateObj.attributes.preset_mode)]]
-            </template>
-          </span>
-        </template>
-        <div class="unit">[[computeTarget(hass, stateObj)]]</div>
-      </div>
-
-      <template is="dom-if" if="[[currentStatus]]">
-        <div class="current">
-          [[localize('ui.card.climate.currently')]]:
-          <div class="unit">[[currentStatus]]</div>
-        </div>
-      </template>
-    `;
-  }
-
-  static get properties() {
-    return {
-      hass: Object,
-      stateObj: Object,
-      currentStatus: {
-        type: String,
-        computed: "computeCurrentStatus(hass, stateObj)",
-      },
-    };
-  }
-
-  computeCurrentStatus(hass, stateObj) {
-    if (!hass || !stateObj) return null;
-    if (stateObj.attributes.current_temperature != null) {
-      return `${stateObj.attributes.current_temperature} ${hass.config.unit_system.temperature}`;
-    }
-    if (stateObj.attributes.current_humidity != null) {
-      return `${stateObj.attributes.current_humidity} %`;
-    }
-    return null;
-  }
-
-  computeTarget(hass, stateObj) {
-    if (!hass || !stateObj) return null;
-    // We're using "!= null" on purpose so that we match both null and undefined.
-    if (
-      stateObj.attributes.target_temp_low != null &&
-      stateObj.attributes.target_temp_high != null
-    ) {
-      return `${stateObj.attributes.target_temp_low}-${stateObj.attributes.target_temp_high} ${hass.config.unit_system.temperature}`;
-    }
-    if (stateObj.attributes.temperature != null) {
-      return `${stateObj.attributes.temperature} ${hass.config.unit_system.temperature}`;
-    }
-    if (
-      stateObj.attributes.target_humidity_low != null &&
-      stateObj.attributes.target_humidity_high != null
-    ) {
-      return `${stateObj.attributes.target_humidity_low}-${stateObj.attributes.target_humidity_high}%`;
-    }
-    if (stateObj.attributes.humidity != null) {
-      return `${stateObj.attributes.humidity} %`;
-    }
-
-    return "";
-  }
-
-  _hasKnownState(state) {
-    return state !== "unknown";
-  }
-
-  _localizeState(localize, stateObj) {
-    const stateString = localize(`component.climate.state._.${stateObj.state}`);
-    return stateObj.attributes.hvac_action
-      ? `${localize(
-          `state_attributes.climate.hvac_action.${stateObj.attributes.hvac_action}`
-        )} (${stateString})`
-      : stateString;
-  }
-
-  _localizePreset(localize, preset) {
-    return localize(`state_attributes.climate.preset_mode.${preset}`) || preset;
-  }
-
-  _renderPreset(attributes) {
-    return (
-      attributes.preset_mode && attributes.preset_mode !== CLIMATE_PRESET_NONE
-    );
-  }
-}
-customElements.define("ha-climate-state", HaClimateState);
diff --git a/src/components/ha-climate-state.ts b/src/components/ha-climate-state.ts
new file mode 100644
index 0000000000..39ece5ee43
--- /dev/null
+++ b/src/components/ha-climate-state.ts
@@ -0,0 +1,139 @@
+import {
+  css,
+  CSSResult,
+  customElement,
+  html,
+  LitElement,
+  property,
+  TemplateResult,
+} from "lit-element";
+import { HassEntity } from "home-assistant-js-websocket";
+
+import { CLIMATE_PRESET_NONE } from "../data/climate";
+import type { HomeAssistant } from "../types";
+
+@customElement("ha-climate-state")
+class HaClimateState extends LitElement {
+  @property({ attribute: false }) public hass!: HomeAssistant;
+
+  @property({ attribute: false }) public stateObj!: HassEntity;
+
+  protected render(): TemplateResult {
+    const currentStatus = this._computeCurrentStatus();
+
+    return html`<div class="target">
+        ${this.stateObj.state !== "unknown"
+          ? html`<span class="state-label">
+              ${this._localizeState()}
+              ${this.stateObj.attributes.preset_mode &&
+              this.stateObj.attributes.preset_mode !== CLIMATE_PRESET_NONE
+                ? html`-
+                  ${this.hass.localize(
+                    `state_attributes.climate.preset_mode.${this.stateObj.attributes.preset_mode}`
+                  ) || this.stateObj.attributes.preset_mode}`
+                : ""}
+            </span>`
+          : ""}
+        <div class="unit">${this._computeTarget()}</div>
+      </div>
+
+      ${currentStatus
+        ? html`<div class="current">
+            ${this.hass.localize("ui.card.climate.currently")}:
+            <div class="unit">${currentStatus}</div>
+          </div>`
+        : ""}`;
+  }
+
+  private _computeCurrentStatus(): string | undefined {
+    if (!this.hass || !this.stateObj) {
+      return undefined;
+    }
+
+    if (this.stateObj.attributes.current_temperature != null) {
+      return `${this.stateObj.attributes.current_temperature} ${this.hass.config.unit_system.temperature}`;
+    }
+
+    if (this.stateObj.attributes.current_humidity != null) {
+      return `${this.stateObj.attributes.current_humidity} %`;
+    }
+
+    return undefined;
+  }
+
+  private _computeTarget(): string {
+    if (!this.hass || !this.stateObj) {
+    	return "";
+    }
+
+    if (
+      this.stateObj.attributes.target_temp_low != null &&
+      this.stateObj.attributes.target_temp_high != null
+    ) {
+      return `${this.stateObj.attributes.target_temp_low}-${this.stateObj.attributes.target_temp_high} ${this.hass.config.unit_system.temperature}`;
+    }
+
+    if (this.stateObj.attributes.temperature != null) {
+      return `${this.stateObj.attributes.temperature} ${this.hass.config.unit_system.temperature}`;
+    }
+    if (
+      this.stateObj.attributes.target_humidity_low != null &&
+      this.stateObj.attributes.target_humidity_high != null
+    ) {
+      return `${this.stateObj.attributes.target_humidity_low}-${this.stateObj.attributes.target_humidity_high}%`;
+    }
+
+    if (this.stateObj.attributes.humidity != null) {
+      return `${this.stateObj.attributes.humidity} %`;
+    }
+
+    return "";
+  }
+
+  private _localizeState(): string {
+    const stateString = this.hass.localize(
+      `component.climate.state._.${this.stateObj.state}`
+    );
+
+    return this.stateObj.attributes.hvac_action
+      ? `${this.hass.localize(
+          `state_attributes.climate.hvac_action.${this.stateObj.attributes.hvac_action}`
+        )} (${stateString})`
+      : stateString;
+  }
+
+  static get styles(): CSSResult {
+    return css`
+      :host {
+        display: flex;
+        flex-direction: column;
+        justify-content: center;
+        white-space: nowrap;
+      }
+
+      .target {
+        color: var(--primary-text-color);
+      }
+
+      .current {
+        color: var(--secondary-text-color);
+      }
+
+      .state-label {
+        font-weight: bold;
+        text-transform: capitalize;
+      }
+
+      .unit {
+        display: inline-block;
+        direction: ltr;
+      }
+    `;
+  }
+}
+
+declare global {
+  interface HTMLElementTagNameMap {
+    "ha-climate-state": HaClimateState;
+  }
+}