Look for a fuse box outside of the house. Many older homes have their fuse boxes outside. Open the fuse box and turn off the power. If the house alarm is not hooked up to a generator, it will not be able to function, and you will be able to pass through as you please.
Find a way to access second-story windows. Many times, in order to cut costs, homeowners will not apply a security system to windows they think are impossible to reach. If you can locate one of these windows, you can easily enter the home without tripping the alarm system.
Experiment with motion sensors. The majority of them work on a passive infrared detection system. This means that the lights and possibly the alarm do not turn on if the sensors do not detect body heat. Bundle up in winter clothing and cover any open areas of skin, like your hands and face, to keep the heat your body gives off to a minimum.
Seek out basement windows that may not be armed. Many basement windows are smaller, and corner-cutting homeowners may not place security on windows they see as impossible to enter. Size up these windows and see if there is any way for you to squeeze through.
Locate a hidden key on the property. Many alarms do not sound if the right key is used. Look under doormats and rocks and in other hiding places for the key.