diff --git a/.coveragerc b/.coveragerc
index a935564791a..5e522016096 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -105,6 +105,9 @@ omit =
     homeassistant/components/envisalink.py
     homeassistant/components/*/envisalink.py
 
+    homeassistant/components/evohome.py
+    homeassistant/components/*/evohome.py
+
     homeassistant/components/fritzbox.py
     homeassistant/components/switch/fritzbox.py
 
diff --git a/homeassistant/components/climate/evohome.py b/homeassistant/components/climate/evohome.py
new file mode 100644
index 00000000000..f0631228fd8
--- /dev/null
+++ b/homeassistant/components/climate/evohome.py
@@ -0,0 +1,371 @@
+"""Support for Honeywell evohome (EMEA/EU-based systems only).
+
+Support for a temperature control system (TCS, controller) with 0+ heating
+zones (e.g. TRVs, relays) and, optionally, a DHW controller.
+
+For more details about this platform, please refer to the documentation at
+https://home-assistant.io/components/climate.evohome/
+"""
+
+from datetime import datetime, timedelta
+import logging
+
+from requests.exceptions import HTTPError
+
+from homeassistant.components.climate import (
+    ClimateDevice,
+    STATE_AUTO,
+    STATE_ECO,
+    STATE_OFF,
+    SUPPORT_OPERATION_MODE,
+    SUPPORT_AWAY_MODE,
+)
+from homeassistant.components.evohome import (
+    CONF_LOCATION_IDX,
+    DATA_EVOHOME,
+    MAX_TEMP,
+    MIN_TEMP,
+    SCAN_INTERVAL_MAX
+)
+from homeassistant.const import (
+    CONF_SCAN_INTERVAL,
+    PRECISION_TENTHS,
+    TEMP_CELSIUS,
+    HTTP_TOO_MANY_REQUESTS,
+)
+_LOGGER = logging.getLogger(__name__)
+
+# these are for the controller's opmode/state and the zone's state
+EVO_RESET = 'AutoWithReset'
+EVO_AUTO = 'Auto'
+EVO_AUTOECO = 'AutoWithEco'
+EVO_AWAY = 'Away'
+EVO_DAYOFF = 'DayOff'
+EVO_CUSTOM = 'Custom'
+EVO_HEATOFF = 'HeatingOff'
+
+EVO_STATE_TO_HA = {
+    EVO_RESET: STATE_AUTO,
+    EVO_AUTO: STATE_AUTO,
+    EVO_AUTOECO: STATE_ECO,
+    EVO_AWAY: STATE_AUTO,
+    EVO_DAYOFF: STATE_AUTO,
+    EVO_CUSTOM: STATE_AUTO,
+    EVO_HEATOFF: STATE_OFF
+}
+
+HA_STATE_TO_EVO = {
+    STATE_AUTO: EVO_AUTO,
+    STATE_ECO: EVO_AUTOECO,
+    STATE_OFF: EVO_HEATOFF
+}
+
+HA_OP_LIST = list(HA_STATE_TO_EVO)
+
+# these are used to help prevent E501 (line too long) violations
+GWS = 'gateways'
+TCS = 'temperatureControlSystems'
+
+# debug codes - these happen occasionally, but the cause is unknown
+EVO_DEBUG_NO_RECENT_UPDATES = '0x01'
+EVO_DEBUG_NO_STATUS = '0x02'
+
+
+def setup_platform(hass, config, add_entities, discovery_info=None):
+    """Create a Honeywell (EMEA/EU) evohome CH/DHW system.
+
+    An evohome system consists of: a controller, with 0-12 heating zones (e.g.
+    TRVs, relays) and, optionally, a DHW controller (a HW boiler).
+
+    Here, we add the controller only.
+    """
+    evo_data = hass.data[DATA_EVOHOME]
+
+    client = evo_data['client']
+    loc_idx = evo_data['params'][CONF_LOCATION_IDX]
+
+    # evohomeclient has no defined way of accessing non-default location other
+    # than using a protected member, such as below
+    tcs_obj_ref = client.locations[loc_idx]._gateways[0]._control_systems[0]    # noqa E501; pylint: disable=protected-access
+
+    _LOGGER.debug(
+        "setup_platform(): Found Controller: id: %s [%s], type: %s",
+        tcs_obj_ref.systemId,
+        tcs_obj_ref.location.name,
+        tcs_obj_ref.modelType
+    )
+    parent = EvoController(evo_data, client, tcs_obj_ref)
+    add_entities([parent], update_before_add=True)
+
+
+class EvoController(ClimateDevice):
+    """Base for a Honeywell evohome hub/Controller device.
+
+    The Controller (aka TCS, temperature control system) is the parent of all
+    the child (CH/DHW) devices.
+    """
+
+    def __init__(self, evo_data, client, obj_ref):
+        """Initialize the evohome entity.
+
+        Most read-only properties are set here.  So are pseudo read-only,
+        for example name (which _could_ change between update()s).
+        """
+        self.client = client
+        self._obj = obj_ref
+
+        self._id = obj_ref.systemId
+        self._name = evo_data['config']['locationInfo']['name']
+
+        self._config = evo_data['config'][GWS][0][TCS][0]
+        self._params = evo_data['params']
+        self._timers = evo_data['timers']
+
+        self._timers['statusUpdated'] = datetime.min
+        self._status = {}
+
+        self._available = False  # should become True after first update()
+
+    def _handle_requests_exceptions(self, err):
+        # evohomeclient v2 api (>=0.2.7) exposes requests exceptions, incl.:
+        # - HTTP_BAD_REQUEST, is usually Bad user credentials
+        # - HTTP_TOO_MANY_REQUESTS, is api usuage limit exceeded
+        # - HTTP_SERVICE_UNAVAILABLE, is often Vendor's fault
+
+        if err.response.status_code == HTTP_TOO_MANY_REQUESTS:
+            # execute a back off: pause, and reduce rate
+            old_scan_interval = self._params[CONF_SCAN_INTERVAL]
+            new_scan_interval = min(old_scan_interval * 2, SCAN_INTERVAL_MAX)
+            self._params[CONF_SCAN_INTERVAL] = new_scan_interval
+
+            _LOGGER.warning(
+                "API rate limit has been exceeded: increasing '%s' from %s to "
+                "%s seconds, and suspending polling for %s seconds.",
+                CONF_SCAN_INTERVAL,
+                old_scan_interval,
+                new_scan_interval,
+                new_scan_interval * 3
+            )
+
+            self._timers['statusUpdated'] = datetime.now() + \
+                timedelta(seconds=new_scan_interval * 3)
+
+        else:
+            raise err
+
+    @property
+    def name(self):
+        """Return the name to use in the frontend UI."""
+        return self._name
+
+    @property
+    def available(self):
+        """Return True if the device is available.
+
+        All evohome entities are initially unavailable. Once HA has started,
+        state data is then retrieved by the Controller, and then the children
+        will get a state (e.g. operating_mode, current_temperature).
+
+        However, evohome entities can become unavailable for other reasons.
+        """
+        return self._available
+
+    @property
+    def supported_features(self):
+        """Get the list of supported features of the Controller."""
+        return SUPPORT_OPERATION_MODE | SUPPORT_AWAY_MODE
+
+    @property
+    def device_state_attributes(self):
+        """Return the device state attributes of the controller.
+
+        This is operating mode state data that is not available otherwise, due
+        to the restrictions placed upon ClimateDevice properties, etc by HA.
+        """
+        data = {}
+        data['systemMode'] = self._status['systemModeStatus']['mode']
+        data['isPermanent'] = self._status['systemModeStatus']['isPermanent']
+        if 'timeUntil' in self._status['systemModeStatus']:
+            data['timeUntil'] = self._status['systemModeStatus']['timeUntil']
+        data['activeFaults'] = self._status['activeFaults']
+        return data
+
+    @property
+    def operation_list(self):
+        """Return the list of available operations."""
+        return HA_OP_LIST
+
+    @property
+    def current_operation(self):
+        """Return the operation mode of the evohome entity."""
+        return EVO_STATE_TO_HA.get(self._status['systemModeStatus']['mode'])
+
+    @property
+    def target_temperature(self):
+        """Return the average target temperature of the Heating/DHW zones."""
+        temps = [zone['setpointStatus']['targetHeatTemperature']
+                 for zone in self._status['zones']]
+
+        avg_temp = round(sum(temps) / len(temps), 1) if temps else None
+        return avg_temp
+
+    @property
+    def current_temperature(self):
+        """Return the average current temperature of the Heating/DHW zones."""
+        tmp_list = [x for x in self._status['zones']
+                    if x['temperatureStatus']['isAvailable'] is True]
+        temps = [zone['temperatureStatus']['temperature'] for zone in tmp_list]
+
+        avg_temp = round(sum(temps) / len(temps), 1) if temps else None
+        return avg_temp
+
+    @property
+    def temperature_unit(self):
+        """Return the temperature unit to use in the frontend UI."""
+        return TEMP_CELSIUS
+
+    @property
+    def precision(self):
+        """Return the temperature precision to use in the frontend UI."""
+        return PRECISION_TENTHS
+
+    @property
+    def min_temp(self):
+        """Return the minimum target temp (setpoint) of a evohome entity."""
+        return MIN_TEMP
+
+    @property
+    def max_temp(self):
+        """Return the maximum target temp (setpoint) of a evohome entity."""
+        return MAX_TEMP
+
+    @property
+    def is_on(self):
+        """Return true as evohome controllers are always on.
+
+        Operating modes can include 'HeatingOff', but (for example) DHW would
+        remain on.
+        """
+        return True
+
+    @property
+    def is_away_mode_on(self):
+        """Return true if away mode is on."""
+        return self._status['systemModeStatus']['mode'] == EVO_AWAY
+
+    def turn_away_mode_on(self):
+        """Turn away mode on."""
+        self._set_operation_mode(EVO_AWAY)
+
+    def turn_away_mode_off(self):
+        """Turn away mode off."""
+        self._set_operation_mode(EVO_AUTO)
+
+    def _set_operation_mode(self, operation_mode):
+        # Set new target operation mode for the TCS.
+        _LOGGER.debug(
+            "_set_operation_mode(): API call [1 request(s)]: "
+            "tcs._set_status(%s)...",
+            operation_mode
+        )
+        try:
+            self._obj._set_status(operation_mode)                               # noqa: E501; pylint: disable=protected-access
+        except HTTPError as err:
+            self._handle_requests_exceptions(err)
+
+    def set_operation_mode(self, operation_mode):
+        """Set new target operation mode for the TCS.
+
+        Currently limited to 'Auto', 'AutoWithEco' & 'HeatingOff'. If 'Away'
+        mode is needed, it can be enabled via turn_away_mode_on method.
+        """
+        self._set_operation_mode(HA_STATE_TO_EVO.get(operation_mode))
+
+    def _update_state_data(self, evo_data):
+        client = evo_data['client']
+        loc_idx = evo_data['params'][CONF_LOCATION_IDX]
+
+        _LOGGER.debug(
+            "_update_state_data(): API call [1 request(s)]: "
+            "client.locations[loc_idx].status()..."
+        )
+
+        try:
+            evo_data['status'].update(
+                client.locations[loc_idx].status()[GWS][0][TCS][0])
+        except HTTPError as err:  # check if we've exceeded the api rate limit
+            self._handle_requests_exceptions(err)
+        else:
+            evo_data['timers']['statusUpdated'] = datetime.now()
+
+        _LOGGER.debug(
+            "_update_state_data(): evo_data['status'] = %s",
+            evo_data['status']
+        )
+
+    def update(self):
+        """Get the latest state data of the installation.
+
+        This includes state data for the Controller and its child devices, such
+        as the operating_mode of the Controller and the current_temperature
+        of its children.
+
+        This is not asyncio-friendly due to the underlying client api.
+        """
+        evo_data = self.hass.data[DATA_EVOHOME]
+
+        timeout = datetime.now() + timedelta(seconds=55)
+        expired = timeout > self._timers['statusUpdated'] + \
+            timedelta(seconds=evo_data['params'][CONF_SCAN_INTERVAL])
+
+        if not expired:
+            return
+
+        was_available = self._available or \
+            self._timers['statusUpdated'] == datetime.min
+
+        self._update_state_data(evo_data)
+        self._status = evo_data['status']
+
+        if _LOGGER.isEnabledFor(logging.DEBUG):
+            tmp_dict = dict(self._status)
+            if 'zones' in tmp_dict:
+                tmp_dict['zones'] = '...'
+            if 'dhw' in tmp_dict:
+                tmp_dict['dhw'] = '...'
+
+            _LOGGER.debug(
+                "update(%s), self._status = %s",
+                self._id + " [" + self._name + "]",
+                tmp_dict
+            )
+
+        no_recent_updates = self._timers['statusUpdated'] < datetime.now() - \
+            timedelta(seconds=self._params[CONF_SCAN_INTERVAL] * 3.1)
+
+        if no_recent_updates:
+            self._available = False
+            debug_code = EVO_DEBUG_NO_RECENT_UPDATES
+
+        elif not self._status:
+            # unavailable because no status (but how? other than at startup?)
+            self._available = False
+            debug_code = EVO_DEBUG_NO_STATUS
+
+        else:
+            self._available = True
+
+        if not self._available and was_available:
+            # only warn if available went from True to False
+            _LOGGER.warning(
+                "The entity, %s, has become unavailable, debug code is: %s",
+                self._id + " [" + self._name + "]",
+                debug_code
+            )
+
+        elif self._available and not was_available:
+            # this isn't the first re-available (e.g. _after_ STARTUP)
+            _LOGGER.debug(
+                "The entity, %s, has become available",
+                self._id + " [" + self._name + "]"
+            )
diff --git a/homeassistant/components/climate/honeywell.py b/homeassistant/components/climate/honeywell.py
index 6d54695fa7a..c445a495073 100644
--- a/homeassistant/components/climate/honeywell.py
+++ b/homeassistant/components/climate/honeywell.py
@@ -20,7 +20,7 @@ from homeassistant.const import (
     CONF_PASSWORD, CONF_USERNAME, TEMP_CELSIUS, TEMP_FAHRENHEIT,
     ATTR_TEMPERATURE, CONF_REGION)
 
-REQUIREMENTS = ['evohomeclient==0.2.5', 'somecomfort==0.5.2']
+REQUIREMENTS = ['evohomeclient==0.2.7', 'somecomfort==0.5.2']
 
 _LOGGER = logging.getLogger(__name__)
 
diff --git a/homeassistant/components/evohome.py b/homeassistant/components/evohome.py
new file mode 100644
index 00000000000..ceeec407b05
--- /dev/null
+++ b/homeassistant/components/evohome.py
@@ -0,0 +1,145 @@
+"""Support for Honeywell evohome (EMEA/EU-based systems only).
+
+Support for a temperature control system (TCS, controller) with 0+ heating
+zones (e.g. TRVs, relays) and, optionally, a DHW controller.
+
+For more details about this component, please refer to the documentation at
+https://home-assistant.io/components/evohome/
+"""
+
+# Glossary:
+# TCS - temperature control system (a.k.a. Controller, Parent), which can
+# have up to 13 Children:
+#   0-12 Heating zones (a.k.a. Zone), and
+#   0-1 DHW controller, (a.k.a. Boiler)
+
+import logging
+
+from requests.exceptions import HTTPError
+import voluptuous as vol
+
+from homeassistant.const import (
+    CONF_USERNAME,
+    CONF_PASSWORD,
+    CONF_SCAN_INTERVAL,
+    HTTP_BAD_REQUEST
+)
+
+import homeassistant.helpers.config_validation as cv
+from homeassistant.helpers.discovery import load_platform
+
+REQUIREMENTS = ['evohomeclient==0.2.7']
+# If ever > 0.2.7, re-check the work-around wrapper is still required when
+# instantiating the client, below.
+
+_LOGGER = logging.getLogger(__name__)
+
+DOMAIN = 'evohome'
+DATA_EVOHOME = 'data_' + DOMAIN
+
+CONF_LOCATION_IDX = 'location_idx'
+MAX_TEMP = 28
+MIN_TEMP = 5
+SCAN_INTERVAL_DEFAULT = 180
+SCAN_INTERVAL_MAX = 300
+
+CONFIG_SCHEMA = vol.Schema({
+    DOMAIN: vol.Schema({
+        vol.Required(CONF_USERNAME): cv.string,
+        vol.Required(CONF_PASSWORD): cv.string,
+        vol.Optional(CONF_LOCATION_IDX, default=0): cv.positive_int,
+    }),
+}, extra=vol.ALLOW_EXTRA)
+
+# These are used to help prevent E501 (line too long) violations.
+GWS = 'gateways'
+TCS = 'temperatureControlSystems'
+
+
+def setup(hass, config):
+    """Create a Honeywell (EMEA/EU) evohome CH/DHW system.
+
+    One controller with 0+ heating zones (e.g. TRVs, relays) and, optionally, a
+    DHW controller.  Does not work for US-based systems.
+    """
+    evo_data = hass.data[DATA_EVOHOME] = {}
+    evo_data['timers'] = {}
+
+    evo_data['params'] = dict(config[DOMAIN])
+    evo_data['params'][CONF_SCAN_INTERVAL] = SCAN_INTERVAL_DEFAULT
+
+    from evohomeclient2 import EvohomeClient
+
+    _LOGGER.debug("setup(): API call [4 request(s)]: client.__init__()...")
+
+    try:
+        # There's a bug in evohomeclient2 v0.2.7: the client.__init__() sets
+        # the root loglevel when EvohomeClient(debug=?), so remember it now...
+        log_level = logging.getLogger().getEffectiveLevel()
+
+        client = EvohomeClient(
+            evo_data['params'][CONF_USERNAME],
+            evo_data['params'][CONF_PASSWORD],
+            debug=False
+        )
+        # ...then restore it to what it was before instantiating the client
+        logging.getLogger().setLevel(log_level)
+
+    except HTTPError as err:
+        if err.response.status_code == HTTP_BAD_REQUEST:
+            _LOGGER.error(
+                "Failed to establish a connection with evohome web servers, "
+                "Check your username (%s), and password are correct."
+                "Unable to continue. Resolve any errors and restart HA.",
+                evo_data['params'][CONF_USERNAME]
+            )
+            return False  # unable to continue
+
+        raise  # we dont handle any other HTTPErrors
+
+    finally:  # Redact username, password as no longer needed.
+        evo_data['params'][CONF_USERNAME] = 'REDACTED'
+        evo_data['params'][CONF_PASSWORD] = 'REDACTED'
+
+    evo_data['client'] = client
+
+    # Redact any installation data we'll never need.
+    if client.installation_info[0]['locationInfo']['locationId'] != 'REDACTED':
+        for loc in client.installation_info:
+            loc['locationInfo']['streetAddress'] = 'REDACTED'
+            loc['locationInfo']['city'] = 'REDACTED'
+            loc['locationInfo']['locationOwner'] = 'REDACTED'
+            loc[GWS][0]['gatewayInfo'] = 'REDACTED'
+
+    # Pull down the installation configuration.
+    loc_idx = evo_data['params'][CONF_LOCATION_IDX]
+
+    try:
+        evo_data['config'] = client.installation_info[loc_idx]
+
+    except IndexError:
+        _LOGGER.warning(
+            "setup(): Parameter '%s' = %s , is outside its range (0-%s)",
+            CONF_LOCATION_IDX,
+            loc_idx,
+            len(client.installation_info) - 1
+        )
+
+        return False  # unable to continue
+
+    evo_data['status'] = {}
+
+    if _LOGGER.isEnabledFor(logging.DEBUG):
+        tmp_loc = dict(evo_data['config'])
+        tmp_loc['locationInfo']['postcode'] = 'REDACTED'
+        tmp_tcs = tmp_loc[GWS][0][TCS][0]
+        if 'zones' in tmp_tcs:
+            tmp_tcs['zones'] = '...'
+        if 'dhw' in tmp_tcs:
+            tmp_tcs['dhw'] = '...'
+
+        _LOGGER.debug("setup(), location = %s", tmp_loc)
+
+    load_platform(hass, 'climate', DOMAIN)
+
+    return True
diff --git a/homeassistant/const.py b/homeassistant/const.py
index 0bcfcd9d4ad..1d3adf7ee45 100644
--- a/homeassistant/const.py
+++ b/homeassistant/const.py
@@ -410,7 +410,9 @@ HTTP_UNAUTHORIZED = 401
 HTTP_NOT_FOUND = 404
 HTTP_METHOD_NOT_ALLOWED = 405
 HTTP_UNPROCESSABLE_ENTITY = 422
+HTTP_TOO_MANY_REQUESTS = 429
 HTTP_INTERNAL_SERVER_ERROR = 500
+HTTP_SERVICE_UNAVAILABLE = 503
 
 HTTP_BASIC_AUTHENTICATION = 'basic'
 HTTP_DIGEST_AUTHENTICATION = 'digest'
diff --git a/requirements_all.txt b/requirements_all.txt
index a954b2cf94f..6efd9a21d7e 100644
--- a/requirements_all.txt
+++ b/requirements_all.txt
@@ -338,8 +338,9 @@ eternalegypt==0.0.5
 # homeassistant.components.keyboard_remote
 # evdev==0.6.1
 
+# homeassistant.components.evohome
 # homeassistant.components.climate.honeywell
-evohomeclient==0.2.5
+evohomeclient==0.2.7
 
 # homeassistant.components.image_processing.dlib_face_detect
 # homeassistant.components.image_processing.dlib_face_identify
diff --git a/requirements_test_all.txt b/requirements_test_all.txt
index f33b37e01d1..1f7d58ef6aa 100644
--- a/requirements_test_all.txt
+++ b/requirements_test_all.txt
@@ -52,8 +52,9 @@ dsmr_parser==0.11
 # homeassistant.components.sensor.season
 ephem==3.7.6.0
 
+# homeassistant.components.evohome
 # homeassistant.components.climate.honeywell
-evohomeclient==0.2.5
+evohomeclient==0.2.7
 
 # homeassistant.components.feedreader
 # homeassistant.components.sensor.geo_rss_events