Not trying to sway you away from using wireless simply stating the facts, limitations, and the pitfalls of using said method.
They absolutely have a place: I use them in my own install, but they are not the primary sensors, sirens, pgm's of my alarm system.
They are used as a secondary, tertiary, layers to all the hard wired units in the home. Anyone who is serious about security must always consider the layering approach and having back up's in case there are faults, or a very determined thief!
On Topic: Some of the biggest things that will affect your distance is physical make up of the building. If your home or building is made with metal studs, this will affect your system.
Noise, doesn't matter if its the AC, wireless router, cordless phone, microwave, compressor, welder etc. All of these affect to a extent the performance or the lack thereof of wireless alarm sensors.
Power output: The more power output, the further it will transmit. Now some companies try to improve the distance simply by using a higher frequency to lesson the affects of the above interference(s).
With respect to your last Q: I don't care what brand you decide to buy for the wireless sensors. But, I will simply like to affirm, and high light one key area that you need to be aware of.
Walk Test: If and when you decide to purchase your system perform a walk test. This will show you how the sensor will respond at that moment in time.
It will show you the attack time, this is when the sensor will detect movement either fast or slow.
This attack time will be affected by temperatures: So today its 70'F all appears OK, a 3 degree drop up or down will increase / decrease that same attack time.
Plain English: Someone can walk past the motion sensor, or avoid detection until its too late. Window sensors are the same, you will see that you will be able to open the window *** inches before the alarm trips, one day it will be instant, the next it will be several inches if not one foot completely.
TIPS:
Avoid placing the detector in proximity to the following sources of interference:
reflective surfaces, direct air flow, sources of steam/oil vapor, infrared light sources and objects causing temperature changes. Digital Microwave Detection will be hampered if installed close to vibrating metal surfaces, rotating fans, water flow in plumbing pipes or
electromagnetic sources.
Also note, microwave frequencies can penetrate walls, therefore, avoid installing the unit where it can respond to motion on the other side of the protected area's walls.
