Channel 4 will launch a new TV channel called 4Seven next month screening repeats of the programmes viewers and critics have most talked about from the previous seven days, prefaced by a snappy selection of their comments, good and bad.

The channel, which takes its place alongside E4, More4 and Film4, will keep open the weekday 8pm and 10pm slots so that shows that create a critical buzz in newspapers, chatter on social media through Twitter and Facebook, and reaction on the overnight log of comments kept by the broadcaster can be repeated the next day.

"We think it is the first time a channel has incorporated the views of viewers into what goes on air. We will run a montage of comments before the programme starts, the rough with the smooth, not just propaganda," said Dan Brooke, Channel 4's chief marketing and communications officer. The rest of the programmes on 4Seven will be reruns of the most popular ones of the week, with the 9pm slot reserved for the programme shown on Channel 4 at 9pm the previous day. Weekends will be devoted to multiple repeats of the best-rated programmes of the past seven days.

It is also a recognition by the broadcaster, marking its 30th birthday in November, that although there has been massive growth in people using on-demand services, which accounts for 5% of viewing, and catching up on computers via the iPlayer or 4OD service – where use is up 15% on last year – many more viewers still prefer to watch channels scheduled for them.

Brooke, who helped create E4 in 2001, thought up the new channel last December, and it quickly won broad backing, leading to its launch on 4 July.

"Repeats used to be a dirty word, but now there is so much on viewers say they are missing the best stuff they want to see. When we did research we found the appeal of this channel was across the board. People do use online catchup, but viewers really want to watch on a big screen, in their lounge," he said. "It will take five to 10 years or so until we have convergence. This is a bridge. And we will be in profit with it next year."

Though television schedulers carefully research the appeal of their programmes, they are still taken aback by the sudden success or otherwise of audience reactions. The surge in audiences for US import Homeland is the most recent example, but the most dramatic has been My Big Fat Gypsy Wedding, which started as a single documentary two years ago with a total audience of 6.4 million viewers, three times the amount expected. It was then spun out into the hit series.

Tess Alps, executive chair of Thinkbox, which represents commercial TV channels, said: "I think it is a very clever idea and very Channel 4, in the sense that their audience, which trends towards younger adults, use social media disproportionately. People also watch certain TV programmes so they can join in conversations about them."

4Seven dovetails with Channel 4 because it relies on high-impact single documentaries or short series such as the three-parter, The Undateables, which suffer from being over before many potential viewers are drawn in. Examples also include Mummyifying Alan, which won a Bafta award last Sunday, Dambusters: Building the Bouncing Bomb and Make Bradford British. 4Seven will be running next-day repeats of the new series of Top Boy, Black Mirror, Homeland 2 and The Undateables. It has recently renegotiated rights over the programmes supplied by producers to give it more freedom.

Channel 4 started the simple C4+1 – the same schedule as C4, screened an hour later – five years ago, which added a useful 0.9% extra share of viewing to its main channel, and this was copied by ITV and also adopted by Channel 5. 4Seven fits with this attempt to shore up its share of audiences, which has fallen to 6.8%, below the critical 7% share deemed key for the main Channel 4.

Adam Turner, deputy managing director of media agency company Opera, said: "It is an innovative way of encouraging viewers to see the main channel's prime product, to time shift without the complication of a digital video recorder, and therefore helps to protect commercial [advertising] impacts. C4 is to be applauded for its creative approach." "Everyone will be watching to see how it works in practice" said an executive at a rival channel, who did not rule out copying the idea. The BBC, which has to apply for consent to launch new channels, said it had no plans to follow suit.