Today's building codes require smoke detectors in every home. The basic smoke detectors sound an alarm when they sense smoke, which alerts occupants to get out of the house. But a more advanced 'monitored' alarm system not only sounds an alarm; it also calls the fire department. Depending on local requirements, monitored alarm systems may be required.
Additionally, many insurance companies will not insure a residence that is vacant for long periods, as is the case with second homes, unless there is a monitored fire and burglar alarm system installed.
In other cases, homeowners may want to monitor the environment inside the house, such as inside temperatures approaching freezing from a failed furnace, and acting before pipes freeze and burst, or perhaps the homeowner is concerned about leaking water in the basement/crawl space, etc.
