Is 11-13 degrees ok temperature for a bedroom?

My niece is currently staying with an Irish host family in Dublin. Her room's temperature ranges between 11(before go to bed) -13(when heating is on). We have raised this with the owner and all we are asking for is to turn the heating on for 15 mins to 20 mins at night to make it a little warmer. But the owner got very upset and says nobody in Ireland does that(well I defo do that and I'm in Ireland). Is 11-13 degrees the norm in Irish households and are we being unreasonable?