Ductless split systems blend well with water heat systems. They are among the most economical systems because they do not have ductwork passing through uncooled attics or other spaces to gain heat as they pass through; they can not leak air from unsealed and taped joints, because there are none. The indoor unit can cool a large area; my 1100 square foot shore home has one 12,000 btuh unit in the living room that cools the entire home. There are units that can serve more than one indoor unit; so one outdoor unit can serve an indoor wall/ceiling unit in the large area, and a blower unit can serve several bedrooms at the same time. I have a comparison of the different systems that work with hydronics (the tutorial on air conditioning)- just type Hydronic Network in the url box to find it. EMI, Sanyo, Mitsubishi, Goodman are some of the manufacturers of these units.