answer:Your home is already full of radio frequencies. Think of all of the local AM and FM radio and television stations you can receive. The receivers themselves are also sources of electromagnetic radiation. Add the communication systems for emergency responders (police, fire, ambulance, et al). Citizen band radios and amateur (ham) radios provide more. Of course, your cell phone, computer and laptop also radiate radio frequencies, oh and your microwave oven. The addition of a dozen or so intrusion detection devices sending bluetooth or wifi signals will not significantly increase the RF noise. While the cost of devices for a wired home alarm system is less than for a wireless system, the added cost of the installation will likely make it more expensive. Renters are likely to use a wireless system. Since a wired system cannot be easily transferred to a new home, homeowners can add the wired security system to the asking price or go wireless. Depending on your intentions, a mix of wired and wireless devices may provide the most economical system.