diff --git a/archetypal/__init__.py b/archetypal/__init__.py
index ed98e5149..d3929e07f 100644
--- a/archetypal/__init__.py
+++ b/archetypal/__init__.py
@@ -28,6 +28,5 @@
 from .trnsys import *
 from .template import *
 from .core import *
-from .building import *
 from .umi_template import *
 from .cli import *
diff --git a/archetypal/building.py b/archetypal/building.py
deleted file mode 100644
index 0b9e2271f..000000000
--- a/archetypal/building.py
+++ /dev/null
@@ -1,102 +0,0 @@
-################################################################################
-# Module: building.py
-# Description: Functions related to building
-# License: MIT, see full license in LICENSE.txt
-# Web: https://github.com/samuelduchesne/archetypal
-################################################################################
-
-import numpy as np
-import pandas
-import pyomo.core as pyomo
-import pyomo.environ
-from pyomo.opt import SolverFactory
-from .energyseries import EnergySeries
-
-
-def create_fake_profile(
-    x=None,
-    y1={},
-    y2={},
-    normalize=False,
-    profile_type="undefined",
-    sorted=False,
-    ascending=False,
-    units="J",
-):
-    """Utility that generates a generic EnergySeries isntance
-
-    Args:
-        x (np.ndarray): is a linspace. Default is np.linspace(0, 8759, 8760)
-        y1 (dict): {'A':1, 'f':1/8760, 'phy':1, 's':0.5}
-        y2 (dict): {'A':1, 'f':1/24, 'phy':1, 's':0.5}
-        ascending (bool): if True, sorts in ascending order. Implies 'sorted'
-            is also True
-        profile_type (str): name to give the series. eg. 'heating load' or
-            'cooling load'
-        sorted (bool): id True, series will be sorted.
-
-    Returns:
-        EnergySeries: the EnergySeries
-    """
-    if x is None:
-        x = np.linspace(0, 8759, 8760)
-    A1 = y1.get("A", 1)
-    f = y1.get("f", 1 / 8760)
-    w = 2 * np.pi * f
-    phy = y1.get("phy", 1)
-    s = y1.get("s", 0.5)
-    y1 = A1 * np.sin(w * x + phy) + s
-
-    A = y2.get("A", A1)
-    f = y2.get("f", 1 / 24)
-    w = 2 * np.pi * f
-    phy = y2.get("phy", 1)
-    s = y2.get("s", 0.5)
-    y2 = A * np.sin(w * x + phy) + s
-
-    y = y1 + y2
-    return EnergySeries(
-        y,
-        index=x,
-        frequency="1H",
-        units=units,
-        profile_type=profile_type,
-        normalize=normalize,
-        is_sorted=sorted,
-        ascending=ascending,
-    )
-
-
-def discretize(profile, bins=5):
-    m = pyomo.ConcreteModel()
-
-    m.bins = pyomo.Set(initialize=range(bins))
-    m.timesteps = pyomo.Set(initialize=range(8760))
-    m.profile = profile.copy()
-    m.duration = pyomo.Var(m.bins, within=pyomo.NonNegativeIntegers)
-    m.amplitude = pyomo.Var(m.bins, within=pyomo.NonNegativeReals)
-
-    m.total_duration = pyomo.Constraint(
-        m.bins,
-        doc="All duration must be " "smaller or " "equal to 8760",
-        rule=total_duration_rule,
-    )
-
-    m.obj = pyomo.Objective(
-        sense=pyomo.minimize, doc="Minimize the sum of squared errors", rule=obj_rule
-    )
-    optim = SolverFactory("gurobi")
-
-    result = optim.solve(m, tee=True, load_solutions=False)
-
-    m.solutions.load_from(result)
-
-    return m
-
-
-def total_duration_rule(m):
-    return sum(m.duration[i] for i in m.bins) == 8760
-
-
-def obj_rule(m):
-    return sum(m.duration * m.amplitude)
diff --git a/archetypal/idfclass.py b/archetypal/idfclass.py
index 2ee873556..3f46cbe2b 100644
--- a/archetypal/idfclass.py
+++ b/archetypal/idfclass.py
@@ -958,7 +958,7 @@ def run_eplus(
         version (bool, optional): Display version information (default: False)
 
     Returns:
-        tuple: a 1-tuple or a 2-tuple
+        2-tuple: a 1-tuple or a 2-tuple
             - dict: dict of [(title, table), .....]
             - IDF: The IDF object. Only provided if return_idf is True.
     """
diff --git a/archetypal/template/building_template.py b/archetypal/template/building_template.py
index 709127d0b..e1596c6d4 100644
--- a/archetypal/template/building_template.py
+++ b/archetypal/template/building_template.py
@@ -73,7 +73,7 @@ def __init__(
         self.Windows = Windows
 
     def __hash__(self):
-        return hash((self.Name, self.idf.name))
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, BuildingTemplate):
diff --git a/archetypal/template/conditioning.py b/archetypal/template/conditioning.py
index de098738c..4ca627e1b 100644
--- a/archetypal/template/conditioning.py
+++ b/archetypal/template/conditioning.py
@@ -178,7 +178,7 @@ def __add__(self, other):
         return self.combine(other)
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, ZoneConditioning):
diff --git a/archetypal/template/dhw.py b/archetypal/template/dhw.py
index b41ee1f87..d1cf21f36 100644
--- a/archetypal/template/dhw.py
+++ b/archetypal/template/dhw.py
@@ -57,7 +57,7 @@ def __add__(self, other):
         return self.combine(other)
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, DomesticHotWaterSetting):
diff --git a/archetypal/template/gas_material.py b/archetypal/template/gas_material.py
index 6bcf3fe56..7dd24ac2a 100644
--- a/archetypal/template/gas_material.py
+++ b/archetypal/template/gas_material.py
@@ -29,7 +29,7 @@ def __init__(self, *args, Category="Gases", Type="Gas", **kwargs):
         self.Type = Type
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, GasMaterial):
diff --git a/archetypal/template/glazing_material.py b/archetypal/template/glazing_material.py
index 45be9c3a9..04e8e3700 100644
--- a/archetypal/template/glazing_material.py
+++ b/archetypal/template/glazing_material.py
@@ -94,7 +94,7 @@ def __add__(self, other):
         return self.combine(other)
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, GlazingMaterial):
diff --git a/archetypal/template/load.py b/archetypal/template/load.py
index 9fc09bed4..509ee7181 100644
--- a/archetypal/template/load.py
+++ b/archetypal/template/load.py
@@ -99,7 +99,7 @@ def __add__(self, other):
         return self.combine(other)
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, ZoneLoad):
diff --git a/archetypal/template/opaque_construction.py b/archetypal/template/opaque_construction.py
index 239b4b939..b3cbaa1e0 100644
--- a/archetypal/template/opaque_construction.py
+++ b/archetypal/template/opaque_construction.py
@@ -104,7 +104,7 @@ def __add__(self, other):
         return self.combine(other)
 
     def __hash__(self):
-        return hash((self.Name))
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, OpaqueConstruction):
diff --git a/archetypal/template/opaque_material.py b/archetypal/template/opaque_material.py
index bad493cd7..519e0d1d2 100644
--- a/archetypal/template/opaque_material.py
+++ b/archetypal/template/opaque_material.py
@@ -112,7 +112,7 @@ def __add__(self, other):
         return self.combine(other)
 
     def __hash__(self):
-        return hash((self.Name))
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, OpaqueMaterial):
diff --git a/archetypal/template/schedule.py b/archetypal/template/schedule.py
index 6330198b6..5b6614a95 100644
--- a/archetypal/template/schedule.py
+++ b/archetypal/template/schedule.py
@@ -82,7 +82,7 @@ def __str__(self):
         return repr(self)
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, UmiSchedule):
@@ -387,7 +387,7 @@ def get_days(self, epbunch):
         ]
         for day in dayname:
             week_day_schedule_name = epbunch["{}_ScheduleDay_Name".format(day)]
-            blocks.append(self.all_objects[("DaySchedule", week_day_schedule_name)])
+            blocks.append(self.all_objects[hash(("DaySchedule", week_day_schedule_name))])
 
         return blocks
 
@@ -478,7 +478,7 @@ def get_parts(self, epbunch):
                     FromMonth,
                     ToDay,
                     ToMonth,
-                    self.all_objects[("WeekSchedule", week_day_schedule_name)],
+                    self.all_objects[hash(("WeekSchedule", week_day_schedule_name))],
                 )
             )
         return parts
diff --git a/archetypal/template/structure.py b/archetypal/template/structure.py
index fa1837933..82f3958e9 100644
--- a/archetypal/template/structure.py
+++ b/archetypal/template/structure.py
@@ -89,7 +89,7 @@ def __init__(
         self.MassRatios = MassRatios
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, StructureDefinition):
diff --git a/archetypal/template/umi_base.py b/archetypal/template/umi_base.py
index b8f223966..d2ffe76fe 100644
--- a/archetypal/template/umi_base.py
+++ b/archetypal/template/umi_base.py
@@ -28,7 +28,7 @@ def __call__(cls, *args, **kwargs):
             *args:
             **kwargs:
         """
-        key = (cls.mro()[0].__name__, kwargs["Name"])
+        key = hash((cls.mro()[0].__name__, kwargs["Name"]))
         if key not in CREATED_OBJECTS:
             self = cls.__new__(cls, *args, **kwargs)
             cls.__init__(self, *args, **kwargs)
@@ -149,12 +149,12 @@ def _get_predecessors_meta(self, other):
 
     def rename(self, name):
         """renames self as well as the cached object"""
-        key = (self.__class__.mro()[0].__name__, self.Name)
+        key = hash((self.__class__.mro()[0].__name__, self.Name))
         self._cache.pop(key)
         CREATED_OBJECTS.pop(key)
 
         self.Name = name
-        newkey = (self.__class__.mro()[0].__name__, name)
+        newkey = hash((self.__class__.mro()[0].__name__, name))
         self._cache[newkey] = self
         CREATED_OBJECTS[newkey] = self
 
@@ -185,7 +185,7 @@ def get_random_schedule(self):
         )
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.mro()[0].__name__, self.Name))
 
     def to_dict(self):
         return {"$ref": str(self.id)}
@@ -275,13 +275,14 @@ def extend(self, other):
         Returns:
             UmiBase: self
         """
+        self.all_objects.pop(self.__hash__(), None)
         id = self.id
-        new_obj = self + other
+        new_obj = self.combine(other)
         new_obj.__dict__.pop("id")
         new_obj.id = id
         name = new_obj.__dict__.pop("Name")
-        self.__dict__.update(**new_obj.__dict__)
-        self.all_objects.pop((self.__class__.__name__, name))
+        self.__dict__.update(Name=name, **new_obj.__dict__)
+        self.all_objects[self.__hash__()] = self
         return self
 
 
@@ -357,7 +358,7 @@ def __init__(
         self.TransportEnergy = TransportEnergy
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, MaterialBase):
diff --git a/archetypal/template/ventilation.py b/archetypal/template/ventilation.py
index f7660925d..17dde4034 100644
--- a/archetypal/template/ventilation.py
+++ b/archetypal/template/ventilation.py
@@ -131,7 +131,7 @@ def __add__(self, other):
         return self.combine(other)
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, VentilationSetting):
diff --git a/archetypal/template/window.py b/archetypal/template/window.py
index 3c6e479d8..c83f22b37 100644
--- a/archetypal/template/window.py
+++ b/archetypal/template/window.py
@@ -61,7 +61,7 @@ def __init__(
         self.Layers = None
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, WindowConstruction):
@@ -310,7 +310,7 @@ def __str__(self):
         return repr(self)
 
     def __hash__(self):
-        return hash(self.Name)
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, WindowSetting):
diff --git a/archetypal/template/zone.py b/archetypal/template/zone.py
index 71a9edb91..9a553b7a9 100644
--- a/archetypal/template/zone.py
+++ b/archetypal/template/zone.py
@@ -28,16 +28,18 @@
     DomesticHotWaterSetting,
     OpaqueConstruction,
     WindowSetting,
-)
+    CREATED_OBJECTS)
 
 
-class Zone(UmiBase, metaclass=Unique):
+class Zone(UmiBase):
     """Class containing HVAC settings: Conditioning, Domestic Hot Water, Loads,
     Ventilation, adn Consructions
 
     .. image:: ../images/template/zoneinfo-zone.png
     """
 
+    _cache = {}
+
     def __init__(
         self,
         Conditioning=None,
@@ -92,6 +94,9 @@ def __init__(
         self._area = kwargs.get("area", None)
         self._volume = kwargs.get("volume", None)
 
+        self._cache[hash(self)] = self
+        CREATED_OBJECTS[hash(self)] = self
+
     def __add__(self, other):
         """
         Args:
@@ -101,7 +106,7 @@ def __add__(self, other):
         return self.combine(other)
 
     def __hash__(self):
-        return hash((self.Name, self.idf.name))
+        return hash((self.Name, id(self.idf)))
 
     def __eq__(self, other):
         if not isinstance(other, Zone):
@@ -322,20 +327,19 @@ def from_json(cls, *args, **kwargs):
         return zone
 
     @classmethod
-    def from_zone_epbunch(cls, zone_ep, **kwargs):
+    def from_zone_epbunch(cls, zone_ep, sql):
         """Create a Zone object from an eppy 'ZONE' epbunch.
 
         Args:
-            zone_ep (EpBunch):
-            **kwargs:
+            zone_ep (EpBunch): The Zone EpBunch.
+            sql (dict): The sql dict for this IDF object.
         """
-        cached = cls.get_cached(zone_ep.Name)
+        cached = cls.get_cached(zone_ep.Name, zone_ep.theidf)
         if cached:
             return cached
         start_time = time.time()
         log('\nConstructing :class:`Zone` for zone "{}"'.format(zone_ep.Name))
         name = zone_ep.Name
-        sql = kwargs.get("sql")
         zone = cls(
             Name=name,
             idf=zone_ep.theidf,
@@ -362,14 +366,16 @@ def from_zone_epbunch(cls, zone_ep, **kwargs):
         return zone
 
     @classmethod
-    def get_cached(cls, name):
-        """Retrieve the cached object by Name. If not, returns None.
+    def get_cached(cls, name, idf):
+        """Retrieve the cached object by Name and idf name. If not, returns
+        None.
 
         Args:
             name (str): The name of the object in the cache.
+            idf (IDF): The :class:`IDF` object.
         """
         try:
-            cached = cls._cache[(cls.mro()[0].__name__, name)]
+            cached = cls._cache[hash((name, id(idf)))]
         except KeyError:
             return None
         else:
@@ -751,7 +757,7 @@ def __add__(self, other):
         return self.combine(other)
 
     def __hash__(self):
-        return hash((self.Name, self.idf.name))
+        return hash((self.__class__.__name__, self.Name))
 
     def __eq__(self, other):
         if not isinstance(other, ZoneConstructionSet):
@@ -778,6 +784,7 @@ def combine(self, other, weights=None):
 
         Args:
             other (ZoneConstructionSet):
+            weights:
 
         Returns:
             (ZoneConstructionSet): the combined ZoneConstructionSet object.
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 4f5915cbb..b2f5682b3 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -15,8 +15,8 @@ def test_reduce(self, config):
         necb = Path("tests/input_data/necb")
         test_file = examples / "2ZoneDataCenterHVAC_wEconomizer.idf"
         test_file_list = [
-            "tests/input_data/trnsys/ASHRAE90.1_Warehouse_STD2004_Rochester.idf",
-            "tests/input_data/trnsys/ASHRAE90.1_RestaurantSitDown_STD2004_Rochester.idf",
+            "tests/input_data/umi_samples/B_Off_0.idf",
+            "tests/input_data/umi_samples/B_Res_0_Masonry.idf",
         ]
         test_files = necb.glob("*Retail*.idf")
         result = runner.invoke(
diff --git a/tests/test_template.py b/tests/test_template.py
index 272cc7685..2e7b4ff28 100644
--- a/tests/test_template.py
+++ b/tests/test_template.py
@@ -13,7 +13,7 @@ def small_idf(config):
     file = "tests/input_data/umi_samples/B_Off_0.idf"
     w = "tests/input_data/CAN_PQ_Montreal.Intl.AP.716270_CWEC.epw"
     idf = ar.load_idf(file)
-    sql = ar.run_eplus(
+    sql: dict = ar.run_eplus(
         file,
         weather_file=w,
         prep_outputs=True,
@@ -331,6 +331,7 @@ def test_iadd_glazing_material(self):
     def test_hash_eq_glaz_mat(self, config):
         """Test equality and hashing of :class:`OpaqueConstruction`"""
         from copy import copy
+
         sg_a = ar.calc_simple_glazing(0.763, 2.716, 0.812)
         mat_a = ar.GlazingMaterial(Name="mat_ia", **sg_a)
         mat_b = copy(mat_a)
@@ -854,9 +855,11 @@ def test_iadd_zoneconstructionset(self, small_idf):
         zone_core = idf.getobject("ZONE", core_name)
         zone_perim = idf.getobject("ZONE", perim_name)
 
-        z_core = ar.ZoneConstructionSet.from_zone(ar.Zone.from_zone_epbunch(zone_core))
+        z_core = ar.ZoneConstructionSet.from_zone(
+            ar.Zone.from_zone_epbunch(zone_core, sql=sql)
+        )
         z_perim = ar.ZoneConstructionSet.from_zone(
-            ar.Zone.from_zone_epbunch(zone_perim)
+            ar.Zone.from_zone_epbunch(zone_perim, sql=sql)
         )
         id_ = z_core.id
         z_core += z_perim
@@ -1589,8 +1592,8 @@ def test_iadd_zone(self, small_idf):
         zone_core = idf.getobject("ZONE", core_name)
         zone_perim = idf.getobject("ZONE", perim_name)
 
-        z_core = ar.Zone.from_zone_epbunch(zone_core)
-        z_perim = ar.Zone.from_zone_epbunch(zone_perim)
+        z_core = ar.Zone.from_zone_epbunch(zone_core, sql=sql)
+        z_perim = ar.Zone.from_zone_epbunch(zone_perim, sql=sql)
         volume = z_core.volume + z_perim.volume  # save volume before changing
         area = z_core.area + z_perim.area  # save area before changing
 
@@ -1610,7 +1613,7 @@ def test_hash_eq_zone(self, small_idf):
         from archetypal.template import Zone
         from copy import copy
 
-        idf, sql = small_idf
+        idf, sql = map(deepcopy, small_idf)
         clear_cache()
         zone_ep = idf.idfobjects["ZONE"][0]
         zone = Zone.from_zone_epbunch(zone_ep, sql=sql)
@@ -1664,7 +1667,7 @@ def test_hash_eq_zone(self, small_idf):
         assert idf is not idf_2
         assert zone_ep is not zone_ep_3
         assert zone_ep != zone_ep_3
-        assert hash(zone) == hash(zone_3)
+        assert hash(zone) != hash(zone_3)
         assert id(zone) != id(zone_3)
         assert zone is not zone_3
         assert zone == zone_3