Comcast's streaming service is now live in Chicago.

For $15 per month, Xfinity Internet users can access broadcast channels and HBO on a laptop, tablet, or smartphone while connected to their home network or public Wi-Fi. Customers can also watch on-demand programs with Streampix and recorded content saved to a cloud DVR.

Announced in July, Comcast Stream TV launched in Boston earlier this month, and will soon expand to Seattle before rolling out to Comcast's entire footprint in early 2016.

Notably, Stream TV will not eat into a customer's monthly data allotment. "Stream TV is a cable streaming service delivered over Comcast's cable system, not over the Internet," Comcast says on its FAQ page. "Therefore, Stream TV data usage will not be counted towards your Xfinity Internet monthly data usage."

As Comcast told Ars Technica, "a Comcast customer who pays for 50Mbps Internet speed would still have a full 50Mbps for other online services while using Stream TV."

In some regions, Comcast is capping monthly data usage at 300GB (up from 250GB a few years ago) and charging $30 extra per month for unlimited access.

These type of exemptions have become more popular lately; T-Mobile recently announced that video streaming would not cut into a mobile customer's monthly data allotment (though streams are capped at 480p). This has prompted concern about possible net neutrality violations, but at least when it comes to T-Mobile, the FCC is not concerned.

As for Stream TV, customers can visit xfinity.com/streamtv to sign up for immediate access.

"We want to make ordering and accessing Stream TV as simple as possible for our customers and let them start watching favorite content as quickly as possible," Matt Strauss, executive vice president and general manager of Comcast video services, said in a statement.