diff --git a/cf_units/__init__.py b/cf_units/__init__.py
index 0f86af93..6b57f4cb 100644
--- a/cf_units/__init__.py
+++ b/cf_units/__init__.py
@@ -841,15 +841,15 @@ def __init__(self, unit, calendar=None):
             unit = _NO_UNIT_STRING
         else:
             category = _CATEGORY_UDUNIT
-            if six.PY2:
-                str_unit = unit.encode(sys.getdefaultencoding(), 'replace')
+            if six.PY2 and not isinstance(unit, six.text_type):
+                str_unit = unit.encode('utf8')
             else:
                 str_unit = unit
             try:
                 ut_unit = _ud.parse(_ud_system, unit.encode('utf8'), encoding)
             except _ud.UdunitsError as e:
                 self._propogate_error(
-                    'Failed to parse unit "%s"' % str_unit, e)
+                    u'Failed to parse unit "{}"'.format(str_unit), e)
             if _OP_SINCE in unit.lower():
                 if calendar is None:
                     calendar_ = CALENDAR_GREGORIAN
@@ -884,7 +884,10 @@ def _propogate_error(self, msg, ud_err):
 
         """
         error_msg = ': "%s"' % ud_err.error_msg() if ud_err.errnum != 0 else ''
-        raise ValueError('[%s] %s%s' % (ud_err.status_msg(), msg, error_msg))
+        msg = '[%s] %s%s' % (ud_err.status_msg(), msg, error_msg)
+        if six.PY2:
+            msg = msg.encode('utf8')
+        raise ValueError(msg)
 
     # NOTE:
     # "__getstate__" and "__setstate__" functions are defined here to
@@ -1462,10 +1465,13 @@ def __str__(self):
             'miles/hour'
 
         """
-        r = self.origin or self.symbol
-        if six.PY2 and sys.getdefaultencoding() == 'ascii':
-            r = r.encode('ascii', 'replace')
-        return r
+        return self.origin or self.symbol
+
+    if six.PY2:
+        __unicode__ = __str__
+
+        def __str__(self):
+            return unicode(self).encode('utf8')
 
     def __repr__(self):
         """
@@ -1482,12 +1488,11 @@ def __repr__(self):
             "Unit('meters')"
 
         """
-
         if self.calendar is None:
-            result = "%s('%s')" % (self.__class__.__name__, self)
+            result = "{}('{}')".format(self.__class__.__name__, self)
         else:
-            result = "%s('%s', calendar='%s')" % (self.__class__.__name__,
-                                                  self, self.calendar)
+            result = "{}('{}', calendar='{}')".format(
+                self.__class__.__name__, self, self.calendar)
         return result
 
     def _offset_common(self, offset):
diff --git a/cf_units/tests/test_unit.py b/cf_units/tests/test_unit.py
index a8070542..4f1c4a48 100644
--- a/cf_units/tests/test_unit.py
+++ b/cf_units/tests/test_unit.py
@@ -79,18 +79,12 @@ def test_calendar_w_unicode(self):
         calendar = unit.CALENDAR_365_DAY
         u = Unit(u'hours\xb2 hours-1 since epoch', calendar=calendar)
         self.assertEqual(u.calendar, calendar)
-        if six.PY2:
-            # Python 2 str MUST return an ascii string, yet the input
-            # was a unicode. We therefore return the ASCII encoded form.
-            expected = 'hours? hours-1 since 1970-01-01 00:00:00'
-        else:
-            expected = 'hours\xb2 hours-1 since 1970-01-01 00:00:00'
-        self.assertEqual(str(u), expected)
+        expected = u'hours² hours-1 since 1970-01-01 00:00:00'
+        self.assertEqual(u.origin, expected)
 
-    @unittest.skipIf(six.PY2, "Unicode literals in str aren't a thing")
     def test_unicode_valid(self):
         # Some unicode characters are allowed.
-        u = Unit('m²')
+        u = Unit(u'm²')
         assert u.symbol == 'm2'
 
     def test_py2k_unicode(self):
@@ -99,9 +93,17 @@ def test_py2k_unicode(self):
 
     def test_unicode_invalid(self):
         # Not all unicode characters are allowed.
-        msg = '[UT_UNKNOWN] Failed to parse unit "ø"'
-        with self.assertRaises(ValueError, msg=msg):
-            Unit('ø')
+
+        if six.PY2:
+            msg = u'[UT_UNKNOWN] Failed to parse unit "ø"'
+            # NOTE: assertRaisesRegex doesn't work with unicode chars in py2 :(
+            with self.assertRaises(ValueError) as e:
+                Unit(u'ø')
+            self.assertIn(msg, e.exception.message.decode('utf8'))
+        else:
+            msg = r'Failed to parse unit \"ø\"'
+            with six.assertRaisesRegex(self, ValueError, msg):
+                Unit('ø')
 
 
 class Test_modulus(unittest.TestCase):