Smart TVs have become an indispensable part of many living rooms. With their Internet connection and apps they allow viewers to stream video from various services.

"Many TVs have Google Assistant, Alexa or Siri integrated or are compatible with them," says TV specialist Ulrike Kuhlmann. This enables the TVs and other smart home devices to be voice controlled.

Then there's the HbbTV feature which can combine Internet content with the television picture.

Because they're connected to the Internet it's pretty much inevitable that smart TVs will collect and transmit user data, some of which can be used for personalised advertising.

A study by Germany's Federal Cartel Office found that a person's TV watching behaviour, app usage, surfing and clicking habits, and even biometric data such as voice or cursor movements can potentially be recorded and evaluated.

"Among other things, the manufacturers can transmit the location and IP address, which can be forwarded, for example, to Netflix and third-party advertising providers," says product tester Andreas Floemer.

This is regardless of whether or not you actually have an account with a streaming provider such as Netflix.

In addition, the device type and location as well as its serial number and the name of the WiFi network can be recorded, all of which theoretically could be used to create a user profile.

According to Kuhlmann, more than 60 servers belonging to the likes of Google, Amazon, and Microsoft are communicated with when you install a smart TV.

"If you use the HbbTV feature, every click can be tracked with the remote control," she says. For that reason it makes sense to deactivate the feature if you're not using it.

How intensively data is collected depends on the manufacturer, explains Floemer: "As a rule, cheaper TV sets collect more data than those in the higher-priced segment."

Kuhlmann says the problem is that "users cannot see what data is being collected. The manufacturers don't reveal that."

According to Germany’s Federal Cartel Office study, the data protection regulations of the smart TV manufacturers examined showed "serious transparency deficiencies."

In addition it's practically impossible for people to find out about a manufacturer's data protection policies before buying one of their devices.

However, there are opportunities to prevent the collection and use of your data, ideally when you first set up the device.

Choosing to prevent data collection "has no influence on the other features, even if the manufacturer suggests it does,” Kuhlmann says.

If some feature subsequently doesn't work, you can always choose to re-enable data access in the TV's settings later.

Another option is to create a blacklist on your Internet router so that the TV can only use certain servers. However, this is time-consuming and really more suitable for experts.

Apps that aren't used by the television should be uninstalled, advises Simone Warnke from Inside-digital.de. Every app, especially if it's not kept updated, is an additional security and data protection risk.

 - dpa