Hardwired is the way to go. The only wireless that I will sell is keyfobs. I don't like relying on wireless for contacts, motions, or smokes. The problem is for the average customer that is not on a maintenance contract, they don't replace batteries. There are systems out there that can give you a full 30 day low battery trouble signal on the keypad and still work. The customer will still procrastinate and end up with a false alarm eventually. Or they call you when you are busy and expect a service call today even though the system will run for awhile without trouble.
If I had to use wireless devices, it would be the Ademco or Inovonics. I have in the past used wireless to protect a contractor service van in the driveway, or a garden shed in the backyard (I still would prefer to slit the ground and run a line out there).
Originally posted by anthonyh: I live in an old brick house with plaster lath walls covered by 1/2 sheetrock, so fishing wires is less then fun to say the least. I am thinking of adding some detectors to the top floor.
You have the idea situation. It's probably a "stick framed" house (no top or bottom plates). Stick a glow rod or fish tape in the wall and it should ride up straight into the attic and poke out of the insulation. I then use a telescopic "grab it" pole to hook the tape and pull it back to me standing on a ladder in the attic hole (I very rarely have to actually enter the attic).
I would mount a zone expander right there next to the access hole or at least a junction point. Most alarms use a common ground return path, so if you pull one quad wire, you can get 3 contacts to run off it or 2 motions with power. I normally pull a 12 conductor wire there. Double up on the power, that leaves 8 wires left for 8 zones using the (-) line as the return common.