It turns out your home security camera may see more of your home than you thought it did. In a teardown of the Nest Cam, a team at ABI Research found that even when "off," the camera draws nearly the same amount of power as when it's fully powered on, meaning it's functional and running even when the indicator light claims otherwise.

Within the Nest Cam app, there is a "Camera On/Off" toggle, which many may think controls the camera's capture of video. However, the ABI team and Jim Mielke, vice president of teardowns at ABI Research, found that the home security camera doesn't draw much less power when it's "off." "In this case, the current drain only changed slightly when given the turn off command, reducing from 370mA to 340mA. Typically a shutdown or standby mode would reduce current by as much as 10 to 100 times. This means that even when a consumer thinks that he or she is successfully turning off this camera, the device is still running."

This may be unsettling for those who own Nest Cams and believed they were totally shutting down the camera when they turned it off from within the app. However, Nest doesn't deny that this is true—a spokesperson for Nest Labs told the BBC in a statement, "When Nest Cam is turned off from the user interface (UI), it does not fully power down, as we expect the camera to be turned on again at any point in time."

While it doesn't change the potential security risks that come along with an "always-on" camera observing your living room, that explanation makes sense when you understand what "on" and "off" mean in terms of the Nest Cam. Turning the camera on in the app means the Nest Cam is actively looking for motion and sound to alert you to—and capturing video while it does so. It doesn't disassociate motion and sound detection from the camera's functionality, so when the camera is on, the Nest Cam is on high alert for disturbances in your home. Of the handful of home security cameras I've recently reviewed, the one that does have an explicit option to turn off the camera is the Canary—it has three modes of watchfulness, with one being "Privacy: Camera and microphone are completely off."

The Nest Cam may be watching, but according to the company, that doesn't mean that footage is going anywhere. The same Nest spokesperson told the BBC, "When Nest Cam is turned off, it completely stops transmitting video to the cloud, meaning it no longer observes its surroundings." Really, it's no longer actively observing and looking for things to ping your smartphone about, but it also shouldn't transmit that video elsewhere. Nest Labs also made a point to note that the camera uses 128-bit secure sockets layer (SSL) encryption, perfect forward secrecy, and a 2,048-bit RSA key that is different for each camera. These precautions make sure your video data can't be accessed, even over the local Wi-Fi network.