Hello,
I live in a 90 year old radiant heated house, no air vent system, outside of Philadelphia. Im going to put in AC but which system is best. Im still working on quotes but here's what I have.
I live in a 11500 sq. foot stone home with finished 3rd floor attic rooms. Not all rooms on 3rd and second floor will be used everyday. Also, we are guessing that there is enough space to put a blower system above the 3rd floor ceiling.

Quotes go like this. 18k for 14 SEER vented system to all but one room (over garage). 22K for 18 SEER Currier system. I am still working on 2 more quotes for the vented system.
The minisplits were suggested to be installed 2 each year, so I can get the 1500.00 Gov credit rebate. Each 2 system job will cost me 7500.00 (b4 rebate) I will need 5 systems total. Estimated costs for full house system is 19-20K. My yard will be a condenser carnival. These systems have SEER ratings of 18 to 27, so I'm happy about that, and I can control when each room is in need of AC, but I have to walk into a hot room first. They filter air, easy accessibility, and come with a heat pump also.

My question> at the end of each month which system is cheapest to run, and which system is best? Definitely on a fence here.

Any words are appreciated.
TJ

I hope you find someone who is really good with those minisplits because you will need them since you will have 5 to keep running. Better read up on those rebates at the .gov site since who knows how many years they will be good for.

BTW what brand minisplit?

Your contractor should have done a manual J and a manual D for your home calculations because it is the only way to determine size of units and size of ducts your home will need. You will need there calculations to figure power usage and then you will need to know how much your utility charges per KW. These calculations should be done by your contractor on your request since they have the other figures from the manual J.

To HVAC1000:
The mini splits are fujitzu the most efficient is a SEER 27. Oh and an edit on my house size... 3850 sq. feet I don't own a football field.my bad there. I will ask each contractor to provide me with the costs numbers to run each system. It's the least they can do to get the job and relax the client, especially since I am investing 20k. Sounded like you are in favor of the vented system, since condenser units will need maintenance and I will have many to upkeep.

FOLLOW UP QUESTION. If I vent only the 3rd and second floor, keep doors open to center hall stairway. Measures 8foot by 22 foot and an stairway opening of 4' by 8' with a middle stair landing, do you think that enough cold air traveling downward would cool the downstairs?
The reason I'm asking is my concern about the size of the return vents. They may make my walls look chopped up and disruptive. But if they stay on the second and third floors the downstairs area will stay original.

Or

Since they are doing the work just let them continue to vent the downstairs.

Your thoughts.
Thanks
Tj

You have a large first floor and I do not believe cool air falling from the upper two is going to do the job on the first floor. I know exactly what you mean about duct work being a problem.

Many,many years ago there was a stone mansion in this area that was just amazing is size and appearance. The owner wanted to add cooling to this beautiful structure and wanted my company to do the job. I refused to tear up the beautiful stone interior since there was no way to disguise the work that had to be done.

After much thought and a owner that would not take no for a answer I decided to use an old design Dunn and Bush (Space Pack) system on the upper floors since this eliminated the super large returns and the first floor was easily serviced by a conventional system since no penetrations had to be made above floor level. To this day no one can actually see the A/C system unless you know exactly where to look especially since we even disguised the outdoor condensing units.



http://www.spacepak.com/at-a-glance.asp

Space Pak: central air for homes that "can't" have central air.

http://www.raymurray.com/PDFs/Editio...20pg%20215.pdf

http://www.spacepak.com/