We're at about 7000 sq ft but we could get away with only worry about the upstairs so 3500.

The same guy that gave a quote on the Mitsubishi as well. I believe it was $5K-10K per room and we would have 2 bedrooms and one great room we'd need to cover. We thought about just doing the bedrooms and keeping the swamp cooler for the great room but we'd still want to replace the swamp cooler with a new one.