Hopefully someone can help shed some light on what the best way to put a central air system in my house is. My house is a single story ranch with a full finished basement. Heating is done like the title says with a boiler and baseboard hot water heat registers. There are 2 zone valves and separate thermostats for the upstairs and downstairs.
Currently the house just has 1 big window unit for cooling the house. It does fair job cooling the kitchen,dinning and living rooms but doesn't do a very good job with the bathrooms and 2 bed rooms because they are down a hallway off of the dinning room. I added ceiling fans which helped some but on really hot, humid days like we are having now in Iowa, not so much.
Now that that is out of the way my question is how can I go about having central A/C with out having to rip out the heating part of it? I'd rather not get rid of it. It works great and we just put new registers in the basement last year. Plus I'd really not want to rip walls apart to run the duct work. The basement ceiling is pretty low and the duct work would have to be run in a header because the floor trusses run perpendicular to how the duct work would need to be run.
Could the duct work be run through the attic? Other then insulation there is nothing up there. It's not big enough for a room or anything else like that. I've been told to look into "mini-split" A/C units. My problem with these is that to me they are basically a window unit with the compressor mounted on the ground. You still don't get the air moving through out the house like you would with an A/C system and duct work.
Final question in my novel here is what could I expect to pay to have this done? I know it's going to be alot but are we talking 5K or 10k or more? There is 1500 sq ft of living area but I don't remember if that is both upstairs and downstairs combined or just the upstairs.