diff --git a/eto/methods/ETo.py b/eto/methods/ETo.py
index b1b24e5..53a95df 100644
--- a/eto/methods/ETo.py
+++ b/eto/methods/ETo.py
@@ -34,7 +34,7 @@ def eto_fao(self, max_ETo=15, min_ETo=0, interp=False, maxgap=15):
 
     ######
     ## ETo equation
-    if 'H' in self.freq:
+    if 'h' in self.freq.lower():
         ETo_FAO = (0.408*self.ts_param['delta']*(self.ts_param['R_n'] - self.ts_param['G']) + self.ts_param['gamma']*37/(self.ts_param['T_mean'] + 273)*self.ts_param['U_2']*(self.ts_param['e_mean'] - self.ts_param['e_a']))/(self.ts_param['delta'] + self.ts_param['gamma']*(1 + 0.34*self.ts_param['U_2']))
     else:
         ETo_FAO = (0.408*self.ts_param['delta']*(self.ts_param['R_n'] - self.ts_param['G']) + self.ts_param['gamma']*900/(self.ts_param['T_mean'] + 273)*self.ts_param['U_2']*(self.ts_param['e_s'] - self.ts_param['e_a']))/(self.ts_param['delta'] + self.ts_param['gamma']*(1 + 0.34*self.ts_param['U_2']))
diff --git a/eto/methods/hargreaves.py b/eto/methods/hargreaves.py
index 70e59a8..0b8ec59 100644
--- a/eto/methods/hargreaves.py
+++ b/eto/methods/hargreaves.py
@@ -32,7 +32,7 @@ def hargreaves(self, max_ETo=15, min_ETo=0, interp=False, maxgap=15):
     ######
     ## ETo equation
 
-    if 'H' in self.freq:
+    if 'h' in self.freq.lower():
         raise ValueError('Hargreaves should not be calculated at time frequencies of less than a day.')
 
     ETo_Har = 0.0023*(self.ts_param['T_mean'] + 17.8)*((self.ts_param['T_max'] - self.ts_param['T_min']) **0.5)*self.ts_param['R_a']*0.408