# Thermal Management

> ![icon-note.gif](public_sys-resources/icon-note.gif) **NOTE**
> The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version.


## Modules to Import

```
import thermal from '@ohos.thermal';
```


## ThermalLevel

Represents the thermal level.

| Name| Default Value| Description|
| -------- | -------- | -------- |
| COOL | 0 | The device is cool, and services are not restricted.|
| NORMAL | 1 | The device is operational but is not cool. You need to pay attention to its heating.|
| WARM | 2 | The device is warm. You need to stop or delay some imperceptible services.|
| HOT | 3 | The device is heating up. You need to stop all imperceptible services and downgrade or reduce the load of other services.|
| OVERHEATED | 4 | The device is overheated. You need to stop all imperceptible services and downgrade or reduce the load of major services.|
| WARNING | 5 | The device is overheated and is about to enter the emergency state. You need to stop all imperceptible services and downgrade major services to the maximum extent.|
| EMERGENCY | 6 | The device has entered the emergency state. You need to stop all services except those for the emergency help purposes.|


## thermal.subscribeThermalLevel

subscribeThermalLevel(callback: AsyncCallback<ThermalLevel>): void

Subscribes to thermal level changes.

**System Capabilities**

SystemCapability.PowerManager.ThermalManager

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;ThermalLevel&gt; | Yes| Callback used to obtain the return value. <br/>Return value: thermal level|

**Example**

```
thermal.subscribeThermalLevel((lev) => {
    console.info("Thermal level is: " + lev);
})
```

## thermal.unsubscribeThermalLevel

unsubscribeThermalLevel(callback?: AsyncCallback<void>): void

Unsubscribes from thermal level changes.

**System Capabilities**

SystemCapability.PowerManager.ThermalManager

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;void&gt; | No| Callback without a return value.|

**Example**

```
thermal.unsubscribeThermalLevel(() => {
    console.info("Unsubscribe completed.");
});
```

## thermal.getThermalLevel

getThermalLevel(): ThermalLevel

Obtains the current thermal level.

**System Capabilities**

SystemCapability.PowerManager.ThermalManager

**Return value**

| Type| Description|
| -------- | -------- |
| ThermalLevel | Thermal level obtained.|

**Example**

```
var lev = thermal.getThermalLevel();
console.info("Thermal level is: " + lev);
```