Sweaty pregnant lady rant

My husband and I and our 3 year old boy live with my parents while we are redoing our home. I live in ky and its 61 degrees today. It's a lovely warm day. Well my dad loves the heat! He has an outdoor wood burning stove that connects to the duct work. It is 77 degrees in the house! I turned it down to 70 and it's still running constantly! If I turn it down any lower he will yell at me...I'm dying!!!! I mean pouring the sweat I can't handle it!