diff --git a/src/boundaries.ts b/src/boundaries.ts
index 6f7668a..5b2e67f 100644
--- a/src/boundaries.ts
+++ b/src/boundaries.ts
@@ -1,20 +1,27 @@
 import { Array, Intersect, Literal, Number, Optional, Record, Static, String, Union } from 'runtypes'
 
-export const NUMBER_TYPES = ['float', 'int', 'uint8', 'uint16', 'uint32', 'uint64'] as const
-const NumberTypesLiterals = NUMBER_TYPES.map(Literal)
-const NumberTypesBoundary = Union(NumberTypesLiterals[0], ...NumberTypesLiterals)
-export type NumberTypes = Static<typeof NumberTypesBoundary>
+export const NUMBER_TYPES = [] as const
+
+const NumberAlikeTypesTypesBoundary = Union(
+    Literal('bool'),
+    Literal('float'),
+    Literal('int'),
+    Literal('uint8'),
+    Literal('uint16'),
+    Literal('uint32'),
+    Literal('uint64'),
+)
+export type NumberAlikeTypes = Static<typeof NumberAlikeTypesTypesBoundary>
 
 export const CharacteristicBoundary = Intersect(
     Record({ type: String, description: String }),
     Union(
         Record({
-            format: NumberTypesBoundary,
+            format: NumberAlikeTypesTypesBoundary,
             value: Optional(Number),
             unit: Optional(String),
         }),
         Record({ format: Literal('string'), value: String }),
-        Record({ format: Literal('bool') }),
     ),
 )
 export type Characteristic = Static<typeof CharacteristicBoundary>
diff --git a/src/metrics.ts b/src/metrics.ts
index fabbbde..5ea2b7b 100644
--- a/src/metrics.ts
+++ b/src/metrics.ts
@@ -1,6 +1,5 @@
 import type { Accessory, Device, Service } from './boundaries'
-import { isType } from './std'
-import { NUMBER_TYPES } from './boundaries'
+import { assertTypeExhausted, isType } from './std'
 import { Service as HapService } from 'hap-nodejs'
 
 export class Metric {
@@ -29,20 +28,33 @@ export function aggregate(devices: Device[], timestamp: Date): Metric[] {
                     ...getServiceLabels(service),
                 }
                 for (const characteristic of service.characteristics) {
-                    for (const numberType of NUMBER_TYPES) {
-                        if (characteristic.format === numberType && typeof characteristic.value !== 'undefined') {
-                            if (METRICS_FILTER.includes(characteristic.description)) {
-                                continue
-                            }
-                            const name = formatName(
-                                uuidToServerName(service.type),
-                                characteristic.description,
-                                characteristic.unit,
-                            )
-                            if (!METRICS_FILTER.includes(name)) {
+                    const format = characteristic.format
+                    switch (format) {
+                        case 'string':
+                            break
+
+                        case 'bool':
+                        case 'float':
+                        case 'int':
+                        case 'uint8':
+                        case 'uint16':
+                        case 'uint32':
+                        case 'uint64':
+                            if (typeof characteristic.value !== 'undefined') {
+                                if (METRICS_FILTER.includes(characteristic.description)) {
+                                    break
+                                }
+                                const name = formatName(
+                                    uuidToServerName(service.type),
+                                    characteristic.description,
+                                    characteristic.unit,
+                                )
                                 metrics.push(new Metric(name, characteristic.value, timestamp, labels))
                             }
-                        }
+                            break
+
+                        default:
+                            assertTypeExhausted(format)
                     }
                 }
             }
@@ -117,10 +129,10 @@ function uuidToServerName(uuid: string): string {
     for (const name of Object.getOwnPropertyNames(HapService)) {
         const maybeService = (HapService as unknown as Record<string, unknown>)[name]
         if (typeof maybeService === 'function' && 'UUID' in maybeService) {
-            if ((maybeService as Record<string,string>)['UUID'] === uuid) {
+            if ((maybeService as Record<string, string>)['UUID'] === uuid) {
                 return name
             }
         }
     }
     throw new Error(`Could not resolve UUID ${uuid} to service`)
-}
\ No newline at end of file
+}
diff --git a/src/std.ts b/src/std.ts
index 6162dd7..626362e 100644
--- a/src/std.ts
+++ b/src/std.ts
@@ -9,3 +9,7 @@ interface TypeMap {
 export function isType<T extends Types>(type: T): (v: unknown) => v is TypeMap[T] {
     return (v: unknown): v is TypeMap[T] => typeof v === type
 }
+
+export function assertTypeExhausted(v: never): never {
+    throw new Error(`Type should be exhausted but is not. Value "${JSON.stringify(v)}`)
+}
diff --git a/tests/aggregator.test.ts b/tests/aggregator.test.ts
index 08ea0ec..231b83f 100644
--- a/tests/aggregator.test.ts
+++ b/tests/aggregator.test.ts
@@ -69,11 +69,16 @@ describe('Metrics aggregator', () => {
         }
 
         expect(aggregate([tpLink], timestamp)).toEqual([
+            new Metric('outlet_on', 0, timestamp, expectedLabelsAccessory1),
+            new Metric('outlet_in_use', 0, timestamp, expectedLabelsAccessory1),
             new Metric('outlet_amperes_a', 0.03, timestamp, expectedLabelsAccessory1),
             new Metric('outlet_total_consumption_kwh', 0.051, timestamp, expectedLabelsAccessory1),
             new Metric('outlet_apparent_power_va', 53248.8, timestamp, expectedLabelsAccessory1),
             new Metric('outlet_volts_v', 230.8, timestamp, expectedLabelsAccessory1),
             new Metric('outlet_consumption_w', 0, timestamp, expectedLabelsAccessory1),
+
+            new Metric('outlet_on', 0, timestamp, expectedLabelsAccessory2),
+            new Metric('outlet_in_use', 0, timestamp, expectedLabelsAccessory2),
             new Metric('outlet_amperes_a', 0.03, timestamp, expectedLabelsAccessory2),
             new Metric('outlet_total_consumption_kwh', 13.025, timestamp, expectedLabelsAccessory2),
             new Metric('outlet_apparent_power_va', 53365.6, timestamp, expectedLabelsAccessory2),
@@ -145,6 +150,7 @@ describe('Metrics aggregator', () => {
 
             new Metric('speaker_active', 1, timestamp, expectedLabels4),
             new Metric('speaker_volume_control_type', 3, timestamp, expectedLabels4),
+            new Metric('speaker_mute', 0, timestamp, expectedLabels4),
             new Metric('speaker_volume_percentage', 50, timestamp, expectedLabels4),
         ])
     })