home security by car alarm installer?

The concept is basically the same.  You'll need to install contact sensors on all the doors and windows.  In a house where the walls have already been closed, putting contacts in the windows can prove to be a daunting task.  Some people choose to count on the motion sensor to do that job.

The motion sensors often look for both heat and motion, in order to indentify and alert to a person in the room instead of a dog or whatever.  Usually the motion sensor is positioned high in a corner of the room near the ceiling to get good coverage of the room in question. You don't want it facing directly at a window because outdoor movement could trigger it.

And of course, there's always the basic alarm system components: controller, siren, battery, etc...  Generally the controller box is mounted in the wall in a closet or laundry room or somewhere where it won't take away from the "décor" of the room.  These usually have a power adapter that you plug into an outlet and secure to the wall.  There should also be a backup battery, which controls basic alarm functions when the power fails.  You should have both an indoor and outdoor siren, though many just have an indoor one.

You can also add fire sensors.  These are installed in kitchens.

And of course, there's the monitoring service.  I'd suggest looking for something that works wirelessly, because the phone-line method where the alarm dials out to the monitoring agency is worthless if the theif remembers to cut the phone wire first.

I find the most commonly used systems are made by a company called DSC. ( http://www.dsc.com).  The last 2 houses we had that had security systems had them made by this company.

I don't know exactly where you can purchase the equipment, but I'm sure you can find one online.  Just make sure you find a reputable dealer and take a look in your town because there may be a place that sells this type of stuff.

I remember back when RadioShack used to sell all the parts and peices for home alarms... those days are long gone, so finding the stuff might be difficult.  I haven't looked myself.

I recommend Honeywell too. Good system.