diff --git a/esphome/components/binary_sensor_map/sensor.py b/esphome/components/binary_sensor_map/sensor.py
index 8b8cd8fc4e..27f4654ded 100644
--- a/esphome/components/binary_sensor_map/sensor.py
+++ b/esphome/components/binary_sensor_map/sensor.py
@@ -3,7 +3,7 @@ import esphome.config_validation as cv
 
 from esphome.components import sensor, binary_sensor
 from esphome.const import CONF_ID, CONF_CHANNELS, CONF_VALUE, CONF_TYPE, UNIT_EMPTY, \
-    ICON_CHECK_CIRCLE_OUTLINE, CONF_BINARY_SENSOR
+    ICON_CHECK_CIRCLE_OUTLINE, CONF_BINARY_SENSOR, CONF_GROUP
 
 DEPENDENCIES = ['binary_sensor']
 
@@ -11,7 +11,6 @@ binary_sensor_map_ns = cg.esphome_ns.namespace('binary_sensor_map')
 BinarySensorMap = binary_sensor_map_ns.class_('BinarySensorMap', cg.Component, sensor.Sensor)
 SensorMapType = binary_sensor_map_ns.enum('SensorMapType')
 
-CONF_GROUP = 'group'
 SENSOR_MAP_TYPES = {
     CONF_GROUP: SensorMapType.BINARY_SENSOR_MAP_TYPE_GROUP,
 }
diff --git a/esphome/components/coolix/climate.py b/esphome/components/coolix/climate.py
index fe74798689..14868a7be0 100644
--- a/esphome/components/coolix/climate.py
+++ b/esphome/components/coolix/climate.py
@@ -1,18 +1,14 @@
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.components import climate, remote_transmitter, remote_receiver, sensor
-from esphome.const import CONF_ID, CONF_SENSOR
+from esphome.components.remote_base import CONF_TRANSMITTER_ID, CONF_RECEIVER_ID
+from esphome.const import CONF_ID, CONF_SENSOR, CONF_SUPPORTS_COOL, CONF_SUPPORTS_HEAT
 
 AUTO_LOAD = ['sensor', 'climate_ir']
 
 coolix_ns = cg.esphome_ns.namespace('coolix')
 CoolixClimate = coolix_ns.class_('CoolixClimate', climate.Climate, cg.Component)
 
-CONF_TRANSMITTER_ID = 'transmitter_id'
-CONF_RECEIVER_ID = 'receiver_id'
-CONF_SUPPORTS_HEAT = 'supports_heat'
-CONF_SUPPORTS_COOL = 'supports_cool'
-
 CONFIG_SCHEMA = cv.All(climate.CLIMATE_SCHEMA.extend({
     cv.GenerateID(): cv.declare_id(CoolixClimate),
     cv.GenerateID(CONF_TRANSMITTER_ID): cv.use_id(remote_transmitter.RemoteTransmitterComponent),
diff --git a/esphome/components/custom/output/__init__.py b/esphome/components/custom/output/__init__.py
index 6042863872..efe6f19dab 100644
--- a/esphome/components/custom/output/__init__.py
+++ b/esphome/components/custom/output/__init__.py
@@ -1,13 +1,12 @@
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.components import output
-from esphome.const import CONF_ID, CONF_LAMBDA, CONF_OUTPUTS, CONF_TYPE
+from esphome.const import CONF_ID, CONF_LAMBDA, CONF_OUTPUTS, CONF_TYPE, CONF_BINARY
 from .. import custom_ns
 
 CustomBinaryOutputConstructor = custom_ns.class_('CustomBinaryOutputConstructor')
 CustomFloatOutputConstructor = custom_ns.class_('CustomFloatOutputConstructor')
 
-CONF_BINARY = 'binary'
 CONF_FLOAT = 'float'
 
 CONFIG_SCHEMA = cv.typed_schema({
diff --git a/esphome/components/dfplayer/__init__.py b/esphome/components/dfplayer/__init__.py
index 78bcfa80f4..890c2bede4 100644
--- a/esphome/components/dfplayer/__init__.py
+++ b/esphome/components/dfplayer/__init__.py
@@ -1,7 +1,7 @@
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome import automation
-from esphome.const import CONF_ID, CONF_TRIGGER_ID
+from esphome.const import CONF_ID, CONF_TRIGGER_ID, CONF_FILE, CONF_DEVICE
 from esphome.components import uart
 
 DEPENDENCIES = ['uart']
@@ -14,10 +14,8 @@ DFPlayerIsPlayingCondition = dfplayer_ns.class_('DFPlayerIsPlayingCondition', au
 
 MULTI_CONF = True
 CONF_FOLDER = 'folder'
-CONF_FILE = 'file'
 CONF_LOOP = 'loop'
 CONF_VOLUME = 'volume'
-CONF_DEVICE = 'device'
 CONF_EQ_PRESET = 'eq_preset'
 CONF_ON_FINISHED_PLAYBACK = 'on_finished_playback'
 
diff --git a/esphome/components/esp32_ble_beacon/esp32_ble_beacon.cpp b/esphome/components/esp32_ble_beacon/esp32_ble_beacon.cpp
index 1f3bf01a86..a61975d02f 100644
--- a/esphome/components/esp32_ble_beacon/esp32_ble_beacon.cpp
+++ b/esphome/components/esp32_ble_beacon/esp32_ble_beacon.cpp
@@ -50,7 +50,7 @@ void ESP32BLEBeacon::ble_core_task(void *params) {
   ble_setup();
 
   while (true) {
-    delay(1000);
+    delay(1000);  // NOLINT
   }
 }
 void ESP32BLEBeacon::ble_setup() {
diff --git a/esphome/components/esp32_ble_tracker/esp32_ble_tracker.cpp b/esphome/components/esp32_ble_tracker/esp32_ble_tracker.cpp
index c578acdaea..7a5bd733a2 100644
--- a/esphome/components/esp32_ble_tracker/esp32_ble_tracker.cpp
+++ b/esphome/components/esp32_ble_tracker/esp32_ble_tracker.cpp
@@ -134,7 +134,7 @@ bool ESP32BLETracker::ble_setup() {
   }
 
   // BLE takes some time to be fully set up, 200ms should be more than enough
-  delay(200);
+  delay(200);  // NOLINT
 
   return true;
 }
diff --git a/esphome/components/esp32_camera/__init__.py b/esphome/components/esp32_camera/__init__.py
index c69e0a5710..81980d9d38 100644
--- a/esphome/components/esp32_camera/__init__.py
+++ b/esphome/components/esp32_camera/__init__.py
@@ -2,7 +2,7 @@ import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome import pins
 from esphome.const import CONF_FREQUENCY, CONF_ID, CONF_NAME, CONF_PIN, CONF_SCL, CONF_SDA, \
-    ESP_PLATFORM_ESP32
+    ESP_PLATFORM_ESP32, CONF_DATA_PINS, CONF_RESET_PIN, CONF_RESOLUTION, CONF_BRIGHTNESS
 
 ESP_PLATFORMS = [ESP_PLATFORM_ESP32]
 DEPENDENCIES = ['api']
@@ -35,23 +35,19 @@ FRAME_SIZES = {
     'UXGA': ESP32CameraFrameSize.ESP32_CAMERA_SIZE_1600X1200,
 }
 
-CONF_DATA_PINS = 'data_pins'
 CONF_VSYNC_PIN = 'vsync_pin'
 CONF_HREF_PIN = 'href_pin'
 CONF_PIXEL_CLOCK_PIN = 'pixel_clock_pin'
 CONF_EXTERNAL_CLOCK = 'external_clock'
 CONF_I2C_PINS = 'i2c_pins'
-CONF_RESET_PIN = 'reset_pin'
 CONF_POWER_DOWN_PIN = 'power_down_pin'
 
 CONF_MAX_FRAMERATE = 'max_framerate'
 CONF_IDLE_FRAMERATE = 'idle_framerate'
-CONF_RESOLUTION = 'resolution'
 CONF_JPEG_QUALITY = 'jpeg_quality'
 CONF_VERTICAL_FLIP = 'vertical_flip'
 CONF_HORIZONTAL_MIRROR = 'horizontal_mirror'
 CONF_CONTRAST = 'contrast'
-CONF_BRIGHTNESS = 'brightness'
 CONF_SATURATION = 'saturation'
 CONF_TEST_PATTERN = 'test_pattern'
 
diff --git a/esphome/components/esp32_touch/esp32_touch.cpp b/esphome/components/esp32_touch/esp32_touch.cpp
index 56bc407e84..ce0028159e 100644
--- a/esphome/components/esp32_touch/esp32_touch.cpp
+++ b/esphome/components/esp32_touch/esp32_touch.cpp
@@ -108,6 +108,8 @@ void ESP32TouchComponent::dump_config() {
 }
 
 void ESP32TouchComponent::loop() {
+  const uint32_t now = millis();
+  bool should_print = this->setup_mode_ && now - this->setup_mode_last_log_print_ > 250;
   for (auto *child : this->children_) {
     uint16_t value;
     if (this->iir_filter_enabled_()) {
@@ -119,14 +121,14 @@ void ESP32TouchComponent::loop() {
     child->value_ = value;
     child->publish_state(value < child->get_threshold());
 
-    if (this->setup_mode_) {
+    if (should_print) {
       ESP_LOGD(TAG, "Touch Pad '%s' (T%u): %u", child->get_name().c_str(), child->get_touch_pad(), value);
     }
   }
 
-  if (this->setup_mode_) {
+  if (should_print) {
     // Avoid spamming logs
-    delay(250);
+    this->setup_mode_last_log_print_ = now;
   }
 }
 
diff --git a/esphome/components/esp32_touch/esp32_touch.h b/esphome/components/esp32_touch/esp32_touch.h
index 7adee23971..45d459a2ff 100644
--- a/esphome/components/esp32_touch/esp32_touch.h
+++ b/esphome/components/esp32_touch/esp32_touch.h
@@ -50,6 +50,7 @@ class ESP32TouchComponent : public Component {
   touch_volt_atten_t voltage_attenuation_{};
   std::vector<ESP32TouchBinarySensor *> children_;
   bool setup_mode_{false};
+  uint32_t setup_mode_last_log_print_{};
   uint32_t iir_filter_{0};
 };
 
diff --git a/esphome/components/mpr121/mpr121.cpp b/esphome/components/mpr121/mpr121.cpp
index a24a703306..2025bc5b3f 100644
--- a/esphome/components/mpr121/mpr121.cpp
+++ b/esphome/components/mpr121/mpr121.cpp
@@ -10,7 +10,7 @@ void MPR121Component::setup() {
   ESP_LOGCONFIG(TAG, "Setting up MPR121...");
   // soft reset device
   this->write_byte(MPR121_SOFTRESET, 0x63);
-  delay(100);
+  delay(100);  // NOLINT
   if (!this->write_byte(MPR121_ECR, 0x0)) {
     this->error_code_ = COMMUNICATION_FAILED;
     this->mark_failed();
diff --git a/esphome/components/mqtt/mqtt_client.cpp b/esphome/components/mqtt/mqtt_client.cpp
index e07204d559..2eb1c52153 100644
--- a/esphome/components/mqtt/mqtt_client.cpp
+++ b/esphome/components/mqtt/mqtt_client.cpp
@@ -201,7 +201,7 @@ void MQTTClientComponent::check_connected() {
   this->status_clear_warning();
   ESP_LOGI(TAG, "MQTT Connected!");
   // MQTT Client needs some time to be fully set up.
-  delay(100);
+  delay(100);  // NOLINT
 
   this->resubscribe_subscriptions_();
 
diff --git a/esphome/components/ms5611/ms5611.cpp b/esphome/components/ms5611/ms5611.cpp
index 33ed6b1899..39bce9f32c 100644
--- a/esphome/components/ms5611/ms5611.cpp
+++ b/esphome/components/ms5611/ms5611.cpp
@@ -19,7 +19,7 @@ void MS5611Component::setup() {
     this->mark_failed();
     return;
   }
-  delay(100);
+  delay(100);  // NOLINT
   for (uint8_t offset = 0; offset < 6; offset++) {
     if (!this->read_byte_16(MS5611_CMD_READ_PROM + (offset * 2), &this->prom_[offset])) {
       this->mark_failed();
diff --git a/esphome/components/ota/ota_component.cpp b/esphome/components/ota/ota_component.cpp
index 6d2a0dd7c3..2041c688eb 100644
--- a/esphome/components/ota/ota_component.cpp
+++ b/esphome/components/ota/ota_component.cpp
@@ -266,7 +266,7 @@ void OTAComponent::handle_() {
   delay(10);
   ESP_LOGI(TAG, "OTA update finished!");
   this->status_clear_warning();
-  delay(100);
+  delay(100);  // NOLINT
   App.safe_reboot();
 
 error:
diff --git a/esphome/components/pmsx003/sensor.py b/esphome/components/pmsx003/sensor.py
index fa9a92d430..0cbaf1bf29 100644
--- a/esphome/components/pmsx003/sensor.py
+++ b/esphome/components/pmsx003/sensor.py
@@ -12,24 +12,24 @@ pmsx003_ns = cg.esphome_ns.namespace('pmsx003')
 PMSX003Component = pmsx003_ns.class_('PMSX003Component', uart.UARTDevice, cg.Component)
 PMSX003Sensor = pmsx003_ns.class_('PMSX003Sensor', sensor.Sensor)
 
-CONF_PMSX003 = 'PMSX003'
-CONF_PMS5003T = 'PMS5003T'
-CONF_PMS5003ST = 'PMS5003ST'
+TYPE_PMSX003 = 'PMSX003'
+TYPE_PMS5003T = 'PMS5003T'
+TYPE_PMS5003ST = 'PMS5003ST'
 
 PMSX003Type = pmsx003_ns.enum('PMSX003Type')
 PMSX003_TYPES = {
-    CONF_PMSX003: PMSX003Type.PMSX003_TYPE_X003,
-    CONF_PMS5003T: PMSX003Type.PMSX003_TYPE_5003T,
-    CONF_PMS5003ST: PMSX003Type.PMSX003_TYPE_5003ST,
+    TYPE_PMSX003: PMSX003Type.PMSX003_TYPE_X003,
+    TYPE_PMS5003T: PMSX003Type.PMSX003_TYPE_5003T,
+    TYPE_PMS5003ST: PMSX003Type.PMSX003_TYPE_5003ST,
 }
 
 SENSORS_TO_TYPE = {
-    CONF_PM_1_0: [CONF_PMSX003, CONF_PMS5003ST],
-    CONF_PM_2_5: [CONF_PMSX003, CONF_PMS5003T, CONF_PMS5003ST],
-    CONF_PM_10_0: [CONF_PMSX003, CONF_PMS5003ST],
-    CONF_TEMPERATURE: [CONF_PMS5003T, CONF_PMS5003ST],
-    CONF_HUMIDITY: [CONF_PMS5003T, CONF_PMS5003ST],
-    CONF_FORMALDEHYDE: [CONF_PMS5003ST],
+    CONF_PM_1_0: [TYPE_PMSX003, TYPE_PMS5003ST],
+    CONF_PM_2_5: [TYPE_PMSX003, TYPE_PMS5003T, TYPE_PMS5003ST],
+    CONF_PM_10_0: [TYPE_PMSX003, TYPE_PMS5003ST],
+    CONF_TEMPERATURE: [TYPE_PMS5003T, TYPE_PMS5003ST],
+    CONF_HUMIDITY: [TYPE_PMS5003T, TYPE_PMS5003ST],
+    CONF_FORMALDEHYDE: [TYPE_PMS5003ST],
 }
 
 
diff --git a/esphome/components/restart/restart_switch.cpp b/esphome/components/restart/restart_switch.cpp
index cd0979b9d3..f66ebc616e 100644
--- a/esphome/components/restart/restart_switch.cpp
+++ b/esphome/components/restart/restart_switch.cpp
@@ -13,8 +13,8 @@ void RestartSwitch::write_state(bool state) {
 
   if (state) {
     ESP_LOGI(TAG, "Restarting device...");
-    // then execute
-    delay(100);  // Let MQTT settle a bit
+    // Let MQTT settle a bit
+    delay(100);  // NOLINT
     App.safe_reboot();
   }
 }
diff --git a/esphome/components/rotary_encoder/sensor.py b/esphome/components/rotary_encoder/sensor.py
index 742096cd5a..214ccbd056 100644
--- a/esphome/components/rotary_encoder/sensor.py
+++ b/esphome/components/rotary_encoder/sensor.py
@@ -3,7 +3,7 @@ import esphome.config_validation as cv
 from esphome import pins, automation
 from esphome.components import sensor
 from esphome.const import CONF_ID, CONF_RESOLUTION, CONF_MIN_VALUE, CONF_MAX_VALUE, UNIT_STEPS, \
-    ICON_ROTATE_RIGHT, CONF_VALUE
+    ICON_ROTATE_RIGHT, CONF_VALUE, CONF_PIN_A, CONF_PIN_B
 
 rotary_encoder_ns = cg.esphome_ns.namespace('rotary_encoder')
 RotaryEncoderResolution = rotary_encoder_ns.enum('RotaryEncoderResolution')
@@ -13,8 +13,6 @@ RESOLUTIONS = {
     4: RotaryEncoderResolution.ROTARY_ENCODER_4_PULSES_PER_CYCLE,
 }
 
-CONF_PIN_A = 'pin_a'
-CONF_PIN_B = 'pin_b'
 CONF_PIN_RESET = 'pin_reset'
 
 RotaryEncoderSensor = rotary_encoder_ns.class_('RotaryEncoderSensor', sensor.Sensor, cg.Component)
diff --git a/esphome/components/scd30/sensor.py b/esphome/components/scd30/sensor.py
index aa863b904a..7a60725276 100644
--- a/esphome/components/scd30/sensor.py
+++ b/esphome/components/scd30/sensor.py
@@ -3,15 +3,13 @@ import esphome.config_validation as cv
 from esphome.components import i2c, sensor
 from esphome.const import CONF_ID, UNIT_PARTS_PER_MILLION, \
     CONF_HUMIDITY, CONF_TEMPERATURE, ICON_PERIODIC_TABLE_CO2, \
-    UNIT_CELSIUS, ICON_THERMOMETER, ICON_WATER_PERCENT, UNIT_PERCENT
+    UNIT_CELSIUS, ICON_THERMOMETER, ICON_WATER_PERCENT, UNIT_PERCENT, CONF_CO2
 
 DEPENDENCIES = ['i2c']
 
 scd30_ns = cg.esphome_ns.namespace('scd30')
 SCD30Component = scd30_ns.class_('SCD30Component', cg.PollingComponent, i2c.I2CDevice)
 
-CONF_CO2 = 'co2'
-
 CONFIG_SCHEMA = cv.Schema({
     cv.GenerateID(): cv.declare_id(SCD30Component),
     cv.Required(CONF_CO2): sensor.sensor_schema(UNIT_PARTS_PER_MILLION,
diff --git a/esphome/components/sgp30/sensor.py b/esphome/components/sgp30/sensor.py
index 0063c29bd3..6329b122fd 100644
--- a/esphome/components/sgp30/sensor.py
+++ b/esphome/components/sgp30/sensor.py
@@ -14,8 +14,8 @@ CONF_TVOC = 'tvoc'
 CONF_BASELINE = 'baseline'
 CONF_UPTIME = 'uptime'
 CONF_COMPENSATION = 'compensation'
-CONF_COMPENSATION_HUMIDITY = 'humidity_source'
-CONF_COMPENSATION_TEMPERATURE = 'temperature_source'
+CONF_HUMIDITY_SOURCE = 'humidity_source'
+CONF_TEMPERATURE_SOURCE = 'temperature_source'
 
 CONFIG_SCHEMA = cv.Schema({
     cv.GenerateID(): cv.declare_id(SGP30Component),
@@ -24,8 +24,8 @@ CONFIG_SCHEMA = cv.Schema({
     cv.Required(CONF_TVOC): sensor.sensor_schema(UNIT_PARTS_PER_BILLION, ICON_RADIATOR, 0),
     cv.Optional(CONF_BASELINE): cv.hex_uint16_t,
     cv.Optional(CONF_COMPENSATION): cv.Schema({
-        cv.Required(CONF_COMPENSATION_HUMIDITY): cv.use_id(sensor.Sensor),
-        cv.Required(CONF_COMPENSATION_TEMPERATURE): cv.use_id(sensor.Sensor)
+        cv.Required(CONF_HUMIDITY_SOURCE): cv.use_id(sensor.Sensor),
+        cv.Required(CONF_TEMPERATURE_SOURCE): cv.use_id(sensor.Sensor)
     }),
 }).extend(cv.polling_component_schema('60s')).extend(i2c.i2c_device_schema(0x58))
 
@@ -48,7 +48,7 @@ def to_code(config):
 
     if CONF_COMPENSATION in config:
         compensation_config = config[CONF_COMPENSATION]
-        sens = yield cg.get_variable(compensation_config[CONF_COMPENSATION_HUMIDITY])
+        sens = yield cg.get_variable(compensation_config[CONF_HUMIDITY_SOURCE])
         cg.add(var.set_humidity_sensor(sens))
-        sens = yield cg.get_variable(compensation_config[CONF_COMPENSATION_TEMPERATURE])
+        sens = yield cg.get_variable(compensation_config[CONF_TEMPERATURE_SOURCE])
         cg.add(var.set_temperature_sensor(sens))
diff --git a/esphome/components/shutdown/shutdown_switch.cpp b/esphome/components/shutdown/shutdown_switch.cpp
index d27bb8aadc..ce33cd187f 100644
--- a/esphome/components/shutdown/shutdown_switch.cpp
+++ b/esphome/components/shutdown/shutdown_switch.cpp
@@ -14,7 +14,7 @@ void ShutdownSwitch::write_state(bool state) {
 
   if (state) {
     ESP_LOGI(TAG, "Shutting down...");
-    delay(100);  // Let MQTT settle a bit
+    delay(100);  // NOLINT
 
     App.run_safe_shutdown_hooks();
 #ifdef ARDUINO_ARCH_ESP8266
diff --git a/esphome/components/ssd1325_spi/ssd1325_spi.cpp b/esphome/components/ssd1325_spi/ssd1325_spi.cpp
index 1f547f8fd3..399700f1dd 100644
--- a/esphome/components/ssd1325_spi/ssd1325_spi.cpp
+++ b/esphome/components/ssd1325_spi/ssd1325_spi.cpp
@@ -14,7 +14,7 @@ void SPISSD1325::setup() {
   this->cs_->setup();      // OUTPUT
 
   this->init_reset_();
-  delay(500);
+  delay(500);  // NOLINT
   SSD1325::setup();
 }
 void SPISSD1325::dump_config() {
diff --git a/esphome/components/sx1509/binary_sensor/__init__.py b/esphome/components/sx1509/binary_sensor/__init__.py
index e780505edb..9a65524383 100644
--- a/esphome/components/sx1509/binary_sensor/__init__.py
+++ b/esphome/components/sx1509/binary_sensor/__init__.py
@@ -5,7 +5,7 @@ from esphome.const import CONF_ID
 from .. import SX1509Component, sx1509_ns, CONF_SX1509_ID
 
 CONF_ROW = 'row'
-CONF_COLUMN = 'col'
+CONF_COL = 'col'
 
 DEPENDENCIES = ['sx1509']
 
@@ -15,7 +15,7 @@ CONFIG_SCHEMA = binary_sensor.BINARY_SENSOR_SCHEMA.extend({
     cv.GenerateID(): cv.declare_id(SX1509BinarySensor),
     cv.GenerateID(CONF_SX1509_ID): cv.use_id(SX1509Component),
     cv.Required(CONF_ROW): cv.int_range(min=0, max=4),
-    cv.Required(CONF_COLUMN): cv.int_range(min=0, max=4),
+    cv.Required(CONF_COL): cv.int_range(min=0, max=4),
 })
 
 
@@ -23,6 +23,6 @@ def to_code(config):
     var = cg.new_Pvariable(config[CONF_ID])
     yield binary_sensor.register_binary_sensor(var, config)
     hub = yield cg.get_variable(config[CONF_SX1509_ID])
-    cg.add(var.set_row_col(config[CONF_ROW], config[CONF_COLUMN]))
+    cg.add(var.set_row_col(config[CONF_ROW], config[CONF_COL]))
 
     cg.add(hub.register_keypad_binary_sensor(var))
diff --git a/esphome/components/tcl112/climate.py b/esphome/components/tcl112/climate.py
index d21300d946..66af291a17 100644
--- a/esphome/components/tcl112/climate.py
+++ b/esphome/components/tcl112/climate.py
@@ -1,18 +1,14 @@
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.components import climate, remote_transmitter, remote_receiver, sensor
-from esphome.const import CONF_ID, CONF_SENSOR
+from esphome.components.remote_base import CONF_TRANSMITTER_ID, CONF_RECEIVER_ID
+from esphome.const import CONF_ID, CONF_SENSOR, CONF_SUPPORTS_COOL, CONF_SUPPORTS_HEAT
 
 AUTO_LOAD = ['sensor', 'climate_ir']
 
 tcl112_ns = cg.esphome_ns.namespace('tcl112')
 Tcl112Climate = tcl112_ns.class_('Tcl112Climate', climate.Climate, cg.Component)
 
-CONF_TRANSMITTER_ID = 'transmitter_id'
-CONF_RECEIVER_ID = 'receiver_id'
-CONF_SUPPORTS_HEAT = 'supports_heat'
-CONF_SUPPORTS_COOL = 'supports_cool'
-
 CONFIG_SCHEMA = cv.All(climate.CLIMATE_SCHEMA.extend({
     cv.GenerateID(): cv.declare_id(Tcl112Climate),
     cv.GenerateID(CONF_TRANSMITTER_ID): cv.use_id(remote_transmitter.RemoteTransmitterComponent),
diff --git a/esphome/components/template/output/__init__.py b/esphome/components/template/output/__init__.py
index 5cc9e089bd..cc85a9da68 100644
--- a/esphome/components/template/output/__init__.py
+++ b/esphome/components/template/output/__init__.py
@@ -2,13 +2,12 @@ import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome import automation
 from esphome.components import output
-from esphome.const import CONF_ID, CONF_TYPE
+from esphome.const import CONF_ID, CONF_TYPE, CONF_BINARY
 from .. import template_ns
 
 TemplateBinaryOutput = template_ns.class_('TemplateBinaryOutput', output.BinaryOutput)
 TemplateFloatOutput = template_ns.class_('TemplateFloatOutput', output.FloatOutput)
 
-CONF_BINARY = 'binary'
 CONF_FLOAT = 'float'
 CONF_WRITE_ACTION = 'write_action'
 
diff --git a/esphome/components/waveshare_epaper/waveshare_epaper.h b/esphome/components/waveshare_epaper/waveshare_epaper.h
index 13aebd4ec9..eff6b895a9 100644
--- a/esphome/components/waveshare_epaper/waveshare_epaper.h
+++ b/esphome/components/waveshare_epaper/waveshare_epaper.h
@@ -45,9 +45,9 @@ class WaveshareEPaper : public PollingComponent,
   void reset_() {
     if (this->reset_pin_ != nullptr) {
       this->reset_pin_->digital_write(false);
-      delay(200);
+      delay(200);  // NOLINT
       this->reset_pin_->digital_write(true);
-      delay(200);
+      delay(200);  // NOLINT
     }
   }
 
@@ -144,7 +144,7 @@ class WaveshareEPaper4P2In : public WaveshareEPaper {
     // COMMAND PANEL SETTING
     this->command(0x00);
 
-    delay(100);
+    delay(100);  // NOLINT
 
     // COMMAND POWER SETTING
     this->command(0x01);
@@ -153,7 +153,7 @@ class WaveshareEPaper4P2In : public WaveshareEPaper {
     this->data(0x00);
     this->data(0x00);
     this->data(0x00);
-    delay(100);
+    delay(100);  // NOLINT
 
     // COMMAND POWER OFF
     this->command(0x02);
diff --git a/esphome/components/wifi/wifi_component.cpp b/esphome/components/wifi/wifi_component.cpp
index 0608f222f7..cb664d3cc3 100644
--- a/esphome/components/wifi/wifi_component.cpp
+++ b/esphome/components/wifi/wifi_component.cpp
@@ -481,7 +481,7 @@ void WiFiComponent::retry_connect() {
     // If retry failed for more than 5 times, let's restart STA
     ESP_LOGW(TAG, "Restarting WiFi adapter...");
     this->wifi_mode_(false, {});
-    delay(100);
+    delay(100);  // NOLINT
     this->num_retried_ = 0;
   } else {
     this->num_retried_++;
diff --git a/esphome/components/yashima/climate.py b/esphome/components/yashima/climate.py
index 5d33670fb5..4c4b98d9e7 100644
--- a/esphome/components/yashima/climate.py
+++ b/esphome/components/yashima/climate.py
@@ -1,17 +1,14 @@
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.components import climate, remote_transmitter, sensor
-from esphome.const import CONF_ID, CONF_SENSOR
+from esphome.components.remote_base import CONF_TRANSMITTER_ID
+from esphome.const import CONF_ID, CONF_SENSOR, CONF_SUPPORTS_COOL, CONF_SUPPORTS_HEAT
 
 AUTO_LOAD = ['sensor']
 
 yashima_ns = cg.esphome_ns.namespace('yashima')
 YashimaClimate = yashima_ns.class_('YashimaClimate', climate.Climate, cg.Component)
 
-CONF_TRANSMITTER_ID = 'transmitter_id'
-CONF_SUPPORTS_HEAT = 'supports_heat'
-CONF_SUPPORTS_COOL = 'supports_cool'
-
 CONFIG_SCHEMA = cv.All(climate.CLIMATE_SCHEMA.extend({
     cv.GenerateID(): cv.declare_id(YashimaClimate),
     cv.GenerateID(CONF_TRANSMITTER_ID): cv.use_id(remote_transmitter.RemoteTransmitterComponent),
diff --git a/esphome/const.py b/esphome/const.py
index 84bef47e47..a7e0c2df93 100644
--- a/esphome/const.py
+++ b/esphome/const.py
@@ -63,8 +63,8 @@ CONF_BROKER = 'broker'
 CONF_BSSID = 'bssid'
 CONF_BUFFER_SIZE = 'buffer_size'
 CONF_BUILD_PATH = 'build_path'
-CONF_BUSY_PIN = 'busy_pin'
 CONF_BUS_VOLTAGE = 'bus_voltage'
+CONF_BUSY_PIN = 'busy_pin'
 CONF_CALIBRATE_LINEAR = 'calibrate_linear'
 CONF_CALIBRATION = 'calibration'
 CONF_CAPACITANCE = 'capacitance'
@@ -84,23 +84,23 @@ CONF_CO2 = 'co2'
 CONF_CODE = 'code'
 CONF_COLD_WHITE = 'cold_white'
 CONF_COLD_WHITE_COLOR_TEMPERATURE = 'cold_white_color_temperature'
-CONF_COLORS = 'colors'
 CONF_COLOR_CORRECT = 'color_correct'
 CONF_COLOR_TEMPERATURE = 'color_temperature'
+CONF_COLORS = 'colors'
 CONF_COMMAND = 'command'
 CONF_COMMAND_TOPIC = 'command_topic'
 CONF_COMMENT = 'comment'
 CONF_COMMIT = 'commit'
-CONF_COMPONENTS = 'components'
 CONF_COMPONENT_ID = 'component_id'
+CONF_COMPONENTS = 'components'
 CONF_CONDITION = 'condition'
 CONF_CONDITION_ID = 'condition_id'
 CONF_CONDUCTIVITY = 'conductivity'
 CONF_COOL_ACTION = 'cool_action'
 CONF_COUNT_MODE = 'count_mode'
 CONF_CRON = 'cron'
-CONF_CSS_URL = 'css_url'
 CONF_CS_PIN = 'cs_pin'
+CONF_CSS_URL = 'css_url'
 CONF_CURRENT = 'current'
 CONF_CURRENT_OPERATION = 'current_operation'
 CONF_CURRENT_RESISTOR = 'current_resistor'
@@ -122,12 +122,12 @@ CONF_DELTA = 'delta'
 CONF_DEVICE = 'device'
 CONF_DEVICE_CLASS = 'device_class'
 CONF_DIMENSIONS = 'dimensions'
-CONF_DIRECTION = 'direction'
 CONF_DIR_PIN = 'dir_pin'
+CONF_DIRECTION = 'direction'
 CONF_DISCOVERY = 'discovery'
-CONF_DISTANCE = 'distance'
 CONF_DISCOVERY_PREFIX = 'discovery_prefix'
 CONF_DISCOVERY_RETAIN = 'discovery_retain'
+CONF_DISTANCE = 'distance'
 CONF_DIV_RATIO = 'div_ratio'
 CONF_DNS1 = 'dns1'
 CONF_DNS2 = 'dns2'
@@ -152,8 +152,8 @@ CONF_FAMILY = 'family'
 CONF_FAST_CONNECT = 'fast_connect'
 CONF_FILE = 'file'
 CONF_FILTER = 'filter'
-CONF_FILTERS = 'filters'
 CONF_FILTER_OUT = 'filter_out'
+CONF_FILTERS = 'filters'
 CONF_FLASH_LENGTH = 'flash_length'
 CONF_FOR = 'for'
 CONF_FORCE_UPDATE = 'force_update'
@@ -172,8 +172,8 @@ CONF_GREEN = 'green'
 CONF_GROUP = 'group'
 CONF_HARDWARE_UART = 'hardware_uart'
 CONF_HEARTBEAT = 'heartbeat'
-CONF_HEATER = 'heater'
 CONF_HEAT_ACTION = 'heat_action'
+CONF_HEATER = 'heater'
 CONF_HIDDEN = 'hidden'
 CONF_HIGH = 'high'
 CONF_HIGH_VOLTAGE_REFERENCE = 'high_voltage_reference'
@@ -207,8 +207,8 @@ CONF_INVERTED = 'inverted'
 CONF_IP_ADDRESS = 'ip_address'
 CONF_JS_URL = 'js_url'
 CONF_JVC = 'jvc'
-CONF_KEEPALIVE = 'keepalive'
 CONF_KEEP_ON_TIME = 'keep_on_time'
+CONF_KEEPALIVE = 'keepalive'
 CONF_LAMBDA = 'lambda'
 CONF_LEVEL = 'level'
 CONF_LG = 'lg'
@@ -218,9 +218,9 @@ CONF_LIGHTNING_ENERGY = 'lightning_energy'
 CONF_LIGHTNING_THRESHOLD = 'lightning_threshold'
 CONF_LOADED_INTEGRATIONS = 'loaded_integrations'
 CONF_LOCAL = 'local'
+CONF_LOG_TOPIC = 'log_topic'
 CONF_LOGGER = 'logger'
 CONF_LOGS = 'logs'
-CONF_LOG_TOPIC = 'log_topic'
 CONF_LOW = 'low'
 CONF_LOW_VOLTAGE_REFERENCE = 'low_voltage_reference'
 CONF_MAC_ADDRESS = 'mac_address'
@@ -240,13 +240,13 @@ CONF_MAX_VOLTAGE = 'max_voltage'
 CONF_MEASUREMENT_DURATION = 'measurement_duration'
 CONF_MEDIUM = 'medium'
 CONF_METHOD = 'method'
-CONF_MINUTE = 'minute'
-CONF_MINUTES = 'minutes'
 CONF_MIN_LENGTH = 'min_length'
 CONF_MIN_LEVEL = 'min_level'
 CONF_MIN_POWER = 'min_power'
 CONF_MIN_TEMPERATURE = 'min_temperature'
 CONF_MIN_VALUE = 'min_value'
+CONF_MINUTE = 'minute'
+CONF_MINUTES = 'minutes'
 CONF_MISO_PIN = 'miso_pin'
 CONF_MODE = 'mode'
 CONF_MODEL = 'model'
@@ -262,14 +262,13 @@ CONF_NBITS = 'nbits'
 CONF_NEC = 'nec'
 CONF_NETWORKS = 'networks'
 CONF_NOISE_LEVEL = 'noise_level'
-CONF_NUMBER = 'number'
 CONF_NUM_ATTEMPTS = 'num_attempts'
 CONF_NUM_CHANNELS = 'num_channels'
 CONF_NUM_CHIPS = 'num_chips'
 CONF_NUM_LEDS = 'num_leds'
+CONF_NUMBER = 'number'
 CONF_OFFSET = 'offset'
 CONF_ON = 'on'
-CONF_ONE = 'one'
 CONF_ON_BOOT = 'on_boot'
 CONF_ON_CLICK = 'on_click'
 CONF_ON_DOUBLE_CLICK = 'on_double_click'
@@ -288,6 +287,7 @@ CONF_ON_TURN_OFF = 'on_turn_off'
 CONF_ON_TURN_ON = 'on_turn_on'
 CONF_ON_VALUE = 'on_value'
 CONF_ON_VALUE_RANGE = 'on_value_range'
+CONF_ONE = 'one'
 CONF_OPEN_ACTION = 'open_action'
 CONF_OPEN_DURATION = 'open_duration'
 CONF_OPEN_ENDSTOP = 'open_endstop'
@@ -299,11 +299,11 @@ CONF_OSCILLATION_OUTPUT = 'oscillation_output'
 CONF_OSCILLATION_STATE_TOPIC = 'oscillation_state_topic'
 CONF_OTA = 'ota'
 CONF_OUTPUT = 'output'
-CONF_OUTPUTS = 'outputs'
 CONF_OUTPUT_ID = 'output_id'
+CONF_OUTPUTS = 'outputs'
 CONF_OVERSAMPLING = 'oversampling'
-CONF_PAGES = 'pages'
 CONF_PAGE_ID = 'page_id'
+CONF_PAGES = 'pages'
 CONF_PANASONIC = 'panasonic'
 CONF_PASSWORD = 'password'
 CONF_PAYLOAD = 'payload'
@@ -311,15 +311,15 @@ CONF_PAYLOAD_AVAILABLE = 'payload_available'
 CONF_PAYLOAD_NOT_AVAILABLE = 'payload_not_available'
 CONF_PHASE_BALANCER = 'phase_balancer'
 CONF_PIN = 'pin'
-CONF_PINS = 'pins'
 CONF_PIN_A = 'pin_a'
 CONF_PIN_B = 'pin_b'
 CONF_PIN_C = 'pin_c'
 CONF_PIN_D = 'pin_d'
+CONF_PINS = 'pins'
 CONF_PLATFORM = 'platform'
 CONF_PLATFORMIO_OPTIONS = 'platformio_options'
-CONF_PM_10_0 = 'pm_10_0'
 CONF_PM_1_0 = 'pm_1_0'
+CONF_PM_10_0 = 'pm_10_0'
 CONF_PM_2_5 = 'pm_2_5'
 CONF_PORT = 'port'
 CONF_POSITION = 'position'
@@ -353,8 +353,8 @@ CONF_RESTORE_MODE = 'restore_mode'
 CONF_RESTORE_STATE = 'restore_state'
 CONF_RESTORE_VALUE = 'restore_value'
 CONF_RETAIN = 'retain'
-CONF_RGBW = 'rgbw'
 CONF_RGB_ORDER = 'rgb_order'
+CONF_RGBW = 'rgbw'
 CONF_RISING_EDGE = 'rising_edge'
 CONF_ROTATION = 'rotation'
 CONF_RS_PIN = 'rs_pin'
@@ -377,14 +377,14 @@ CONF_SEL_PIN = 'sel_pin'
 CONF_SEND_EVERY = 'send_every'
 CONF_SEND_FIRST_AT = 'send_first_at'
 CONF_SENSOR = 'sensor'
-CONF_SENSORS = 'sensors'
 CONF_SENSOR_ID = 'sensor_id'
+CONF_SENSORS = 'sensors'
+CONF_SEQUENCE = 'sequence'
 CONF_SERVERS = 'servers'
 CONF_SERVICE = 'service'
 CONF_SERVICES = 'services'
 CONF_SETUP_MODE = 'setup_mode'
 CONF_SETUP_PRIORITY = 'setup_priority'
-CONF_SEQUENCE = 'sequence'
 CONF_SHUNT_RESISTANCE = 'shunt_resistance'
 CONF_SHUNT_VOLTAGE = 'shunt_voltage'
 CONF_SHUTDOWN_MESSAGE = 'shutdown_message'
@@ -408,6 +408,8 @@ CONF_STEP_PIN = 'step_pin'
 CONF_STOP = 'stop'
 CONF_STOP_ACTION = 'stop_action'
 CONF_SUBNET = 'subnet'
+CONF_SUPPORTS_COOL = 'supports_cool'
+CONF_SUPPORTS_HEAT = 'supports_heat'
 CONF_SWITCHES = 'switches'
 CONF_SYNC = 'sync'
 CONF_TAG = 'tag'
@@ -425,10 +427,10 @@ CONF_TILT = 'tilt'
 CONF_TILT_ACTION = 'tilt_action'
 CONF_TILT_LAMBDA = 'tilt_lambda'
 CONF_TIME = 'time'
+CONF_TIME_ID = 'time_id'
 CONF_TIMEOUT = 'timeout'
 CONF_TIMES = 'times'
 CONF_TIMEZONE = 'timezone'
-CONF_TIME_ID = 'time_id'
 CONF_TIMING = 'timing'
 CONF_TO = 'to'
 CONF_TOLERANCE = 'tolerance'
@@ -449,8 +451,8 @@ CONF_UNIQUE = 'unique'
 CONF_UNIT_OF_MEASUREMENT = 'unit_of_measurement'
 CONF_UPDATE_INTERVAL = 'update_interval'
 CONF_UPDATE_ON_BOOT = 'update_on_boot'
-CONF_USERNAME = 'username'
 CONF_USE_ADDRESS = 'use_address'
+CONF_USERNAME = 'username'
 CONF_UUID = 'uuid'
 CONF_VALUE = 'value'
 CONF_VARIABLES = 'variables'
@@ -470,8 +472,8 @@ CONF_WHITE = 'white'
 CONF_WIDTH = 'width'
 CONF_WIFI = 'wifi'
 CONF_WILL_MESSAGE = 'will_message'
-CONF_WIND_SPEED = 'wind_speed'
 CONF_WIND_DIRECTION_DEGREES = 'wind_direction_degrees'
+CONF_WIND_SPEED = 'wind_speed'
 CONF_WINDOW_SIZE = 'window_size'
 CONF_ZERO = 'zero'
 
@@ -479,8 +481,8 @@ ICON_ARROW_EXPAND_VERTICAL = 'mdi:arrow-expand-vertical'
 ICON_BATTERY = 'mdi:battery'
 ICON_BRIEFCASE_DOWNLOAD = 'mdi:briefcase-download'
 ICON_BRIGHTNESS_5 = 'mdi:brightness-5'
-ICON_CHEMICAL_WEAPON = 'mdi:chemical-weapon'
 ICON_CHECK_CIRCLE_OUTLINE = 'mdi:check-circle-outline'
+ICON_CHEMICAL_WEAPON = 'mdi:chemical-weapon'
 ICON_CURRENT_AC = 'mdi:current-ac'
 ICON_EMPTY = ''
 ICON_FLASH = 'mdi:flash'
@@ -499,26 +501,26 @@ ICON_RESTART = 'mdi:restart'
 ICON_ROTATE_RIGHT = 'mdi:rotate-right'
 ICON_SCALE = 'mdi:scale'
 ICON_SCREEN_ROTATION = 'mdi:screen-rotation'
+ICON_SIGN_DIRECTION = 'mdi:sign-direction'
 ICON_SIGNAL = 'mdi: signal-distance-variant'
 ICON_SIGNAL_DISTANCE_VARIANT = 'mdi:signal'
-ICON_SIGN_DIRECTION = 'mdi:sign-direction'
-ICON_WEATHER_SUNSET = 'mdi:weather-sunset'
-ICON_WEATHER_SUNSET_DOWN = 'mdi:weather-sunset-down'
-ICON_WEATHER_SUNSET_UP = 'mdi:weather-sunset-up'
 ICON_THERMOMETER = 'mdi:thermometer'
 ICON_TIMER = 'mdi:timer'
 ICON_WATER_PERCENT = 'mdi:water-percent'
+ICON_WEATHER_SUNSET = 'mdi:weather-sunset'
+ICON_WEATHER_SUNSET_DOWN = 'mdi:weather-sunset-down'
+ICON_WEATHER_SUNSET_UP = 'mdi:weather-sunset-up'
 ICON_WEATHER_WINDY = 'mdi:weather-windy'
 ICON_WIFI = 'mdi:wifi'
 
 UNIT_AMPERE = 'A'
 UNIT_CELSIUS = u'°C'
 UNIT_DECIBEL = 'dB'
-UNIT_DEGREES = u'°'
 UNIT_DEGREE_PER_SECOND = u'°/s'
+UNIT_DEGREES = u'°'
 UNIT_EMPTY = ''
-UNIT_HZ = 'hz'
 UNIT_HECTOPASCAL = 'hPa'
+UNIT_HZ = 'hz'
 UNIT_KELVIN = 'K'
 UNIT_KILOMETER = 'km'
 UNIT_KILOMETER_PER_HOUR = 'km/h'
@@ -529,8 +531,8 @@ UNIT_MICROGRAMS_PER_CUBIC_METER = u'µg/m³'
 UNIT_MICROSIEMENS_PER_CENTIMETER = u'µS/cm'
 UNIT_MICROTESLA = u'µT'
 UNIT_OHM = u'Ω'
-UNIT_PARTS_PER_MILLION = 'ppm'
 UNIT_PARTS_PER_BILLION = 'ppb'
+UNIT_PARTS_PER_MILLION = 'ppm'
 UNIT_PERCENT = '%'
 UNIT_PULSES_PER_MINUTE = 'pulses/min'
 UNIT_SECOND = 's'
diff --git a/script/ci-custom.py b/script/ci-custom.py
index fff24df0dc..5a98bdd20d 100755
--- a/script/ci-custom.py
+++ b/script/ci-custom.py
@@ -7,6 +7,7 @@ import fnmatch
 import os.path
 import subprocess
 import sys
+import re
 
 
 def find_all(a_str, sub):
@@ -39,6 +40,7 @@ ignore_types = ('.ico', '.woff', '.woff2', '')
 
 LINT_FILE_CHECKS = []
 LINT_CONTENT_CHECKS = []
+LINT_POST_CHECKS = []
 
 
 def run_check(lint_obj, fname, *args):
@@ -84,6 +86,31 @@ def lint_content_check(**kwargs):
     return decorator
 
 
+def lint_post_check(func):
+    _add_check(LINT_POST_CHECKS, func)
+    return func
+
+
+def lint_re_check(regex, **kwargs):
+    prog = re.compile(regex, re.MULTILINE)
+    decor = lint_content_check(**kwargs)
+
+    def decorator(func):
+        def new_func(fname, content):
+            errors = []
+            for match in prog.finditer(content):
+                if 'NOLINT' in match.group(0):
+                    continue
+                lineno = content.count("\n", 0, match.start()) + 1
+                err = func(fname, match)
+                if err is None:
+                    continue
+                errors.append("{} See line {}.".format(err, lineno))
+            return errors
+        return decor(new_func)
+    return decorator
+
+
 def lint_content_find_check(find, **kwargs):
     decor = lint_content_check(**kwargs)
 
@@ -92,9 +119,12 @@ def lint_content_find_check(find, **kwargs):
             find_ = find
             if callable(find):
                 find_ = find(fname, content)
+            errors = []
             for line, col in find_all(content, find_):
                 err = func(fname)
-                return "{err} See line {line}:{col}.".format(err=err, line=line+1, col=col+1)
+                errors.append("{err} See line {line}:{col}."
+                              "".format(err=err, line=line+1, col=col+1))
+            return errors
         return decor(new_func)
     return decorator
 
@@ -143,6 +173,98 @@ def lint_end_newline(fname, content):
     return None
 
 
+CPP_RE_EOL = r'\s*?(?://.*?)?$'
+
+
+def highlight(s):
+    return '\033[36m{}\033[0m'.format(s)
+
+
+@lint_re_check(r'^#define\s+([a-zA-Z0-9_]+)\s+([0-9bx]+)' + CPP_RE_EOL,
+               include=cpp_include, exclude=['esphome/core/log.h'])
+def lint_no_defines(fname, match):
+    s = highlight('static const uint8_t {} = {};'.format(match.group(1), match.group(2)))
+    return ("#define macros for integer constants are not allowed, please use "
+            "{} style instead (replace uint8_t with the appropriate "
+            "datatype). See also Google style guide.".format(s))
+
+
+@lint_re_check(r'^\s*delay\((\d+)\);' + CPP_RE_EOL, include=cpp_include)
+def lint_no_long_delays(fname, match):
+    duration_ms = int(match.group(1))
+    if duration_ms < 50:
+        return None
+    return (
+        "{} - long calls to delay() are not allowed in ESPHome because everything executes "
+        "in one thread. Calling delay() will block the main thread and slow down ESPHome.\n"
+        "If there's no way to work around the delay() and it doesn't execute often, please add "
+        "a '// NOLINT' comment to the line."
+        "".format(highlight(match.group(0).strip()))
+    )
+
+
+@lint_content_check(include=['esphome/const.py'])
+def lint_const_ordered(fname, content):
+    lines = content.splitlines()
+    errors = []
+    for start in ['CONF_', 'ICON_', 'UNIT_']:
+        matching = [(i+1, line) for i, line in enumerate(lines) if line.startswith(start)]
+        ordered = list(sorted(matching, key=lambda x: x[1].replace('_', ' ')))
+        ordered = [(mi, ol) for (mi, _), (_, ol) in zip(matching, ordered)]
+        for (mi, ml), (oi, ol) in zip(matching, ordered):
+            if ml == ol:
+                continue
+            target = next(i for i, l in ordered if l == ml)
+            target_text = next(l for i, l in matching if target == i)
+            errors.append("Constant {} is not ordered, please make sure all constants are ordered. "
+                          "See line {} (should go to line {}, {})"
+                          "".format(highlight(ml), mi, target, target_text))
+    return errors
+
+
+@lint_re_check(r'^\s*CONF_([A-Z_0-9a-z]+)\s+=\s+[\'"](.*?)[\'"]\s*?$', include=['*.py'])
+def lint_conf_matches(fname, match):
+    const = match.group(1)
+    value = match.group(2)
+    const_norm = const.lower()
+    value_norm = value.replace('.', '_')
+    if const_norm == value_norm:
+        return None
+    return ("Constant {} does not match value {}! Please make sure the constant's name matches its "
+            "value!"
+            "".format(highlight('CONF_' + const), highlight(value)))
+
+
+CONF_RE = r'^(CONF_[a-zA-Z0-9_]+)\s*=\s*[\'"].*?[\'"]\s*?$'
+with codecs.open('esphome/const.py', 'r', encoding='utf-8') as f_handle:
+    constants_content = f_handle.read()
+CONSTANTS = [m.group(1) for m in re.finditer(CONF_RE, constants_content, re.MULTILINE)]
+
+CONSTANTS_USES = collections.defaultdict(list)
+
+
+@lint_re_check(CONF_RE, include=['*.py'], exclude=['esphome/const.py'])
+def lint_conf_from_const_py(fname, match):
+    name = match.group(1)
+    if name not in CONSTANTS:
+        CONSTANTS_USES[name].append(fname)
+        return None
+    return ("Constant {} has already been defined in const.py - please import the constant from "
+            "const.py directly.".format(highlight(name)))
+
+
+@lint_post_check
+def lint_constants_usage():
+    errors = []
+    for constant, uses in CONSTANTS_USES.items():
+        if len(uses) < 4:
+            continue
+        errors.append("Constant {} is defined in {} files. Please move all definitions of the "
+                      "constant to const.py (Uses: {})"
+                      "".format(highlight(constant), len(uses), ', '.join(uses)))
+    return errors
+
+
 def relative_cpp_search_text(fname, content):
     parts = fname.split('/')
     integration = parts[2]
@@ -241,6 +363,8 @@ for fname in files:
         continue
     run_checks(LINT_CONTENT_CHECKS, fname, fname, content)
 
+run_checks(LINT_POST_CHECKS, 'POST')
+
 for f, errs in sorted(errors.items()):
     print("\033[0;32m************* File \033[1;32m{}\033[0m".format(f))
     for err in errs: