Some services offer cellular back up should this occur. Look for a home security system with a full line of wireless peripherals, including modules for controlling lights and appliances, thermostats, cameras, motion sensors some can distinguish between a pet and a person, water sensors, and glass break and vibration sensors. Look for long life battery power, too. Lithium sensor batteries, for example, can last three to five years. When they do run low, the system lets you know well in advance. Choose a controller with back up battery so the system will stay active in the event of a power outage or if the Internet is down. If you will be installing smoke alarms you’ll need the extra power of a 24 hour battery back up, not the 4 hour back up offered by many manufacturers. THE COST FOR SECURITY There are two costs to keep in mind when shopping for a home security system. The first is for the equipment and the installation, if you’re having it done by a professional. It can run from a few hundred dollars for a basic installation or less that half of that if you install it yourself to north of $1000 for a full feature system with specialized sensors and wireless smoke and CO detectors. The second is the monthly service charge that includes fees for software driven features and central station monitoring.