In a society that is constantly being monitored with global satellites, cameras and other listening devices, it is only natural to have the urge to maintain what little privacy we have left. Hidden listening devices, more commonly referred to as "bugs," are one of the ways other people can listen in on your conversations. If you suspect your home is being bugged, investigate the area using these techniques to ease your mind.
Scan the area for any suspicious wires or devices that do not belong. Although modern listening devices operate wirelessly, some older models have wires that will give them away.

Perform a sweep of the area to test for any radio waves that do not belong. Most bugs emit radio waves, and you can locate the source using a low-tech sweeping device purchased from electrical magazines or online. Sweeping is a solid method to locate amateur bugs, but more advanced technology can change radio frequencies, making it invisible during a sweep.

Search the area for other recording devices that might be carefully hidden. Recording devices come in all shapes and sizes. Lift the ceiling tiles in a suspended ceiling to check for hidden devices---this is a common place for hiding listening devices because people do not think to look up there. Other possible locations include pens, calculators and other small items.
Check for magnetic fields using sensitive magnetic testing equipment. These devices can sometimes help locate electrical noise emitted by the computerized technology used in digital tape recorders. However, in a home with lots of electronics, computers, and printers, there is a lot of interference, which makes this process difficult.

Use a sensitive infrared camera to search for waste heat emitted by the bug or to look for thermal conductivity. Chill the suspected area briefly with liquid nitrogren and see if there is continued thermal conductivity or waste heat.