I feel your pain.....my house has three distinct "zones" but because it was built 40 yrs ago, they slapped one A/C unit and ductwork in there and expected that to be sufficient to heat and cool a chalet style structure (prow and 30' ceilings in one area, etc). HA! A Mini-split system has helped the living room which has those 30' ceilings....But the guest room upstairs - well you could hang meat in there to cure over the winter thats how cold it stays. I remember now why we prefer new construction to buying older homes......but the property itself and the views were definitely the selling feature here....