Hiding rows based on a certain cell's value which is a formula

Try this instead:

Private Sub Worksheet_Calculate() 

 Application.EnableEvents = False
 
 Rows.Hidden = False

 If Worksheets("Template Sheet").Cells(21, 2).value = "" Then _
 Rows("1:34").Hidden = True
 
 If Worksheets("Template Sheet").Cells(55, 2).value = "" Then _
 Rows("35:68").Hidden = True
 
 If Worksheets("Template Sheet").Cells(89, 2).value = "" Then _
 Rows("69:102").Hidden = True
 
 If Worksheets("Template Sheet").Cells(123, 2).value = "" Then _
 Rows("103:136").Hidden = True
 
 If Worksheets("Template Sheet").Cells(157, 2).value = "" Then _
 Rows("137:170").Hidden = True
 
 Application.EnableEvents = True

 End Sub