The British love affair with television is intensifying despite a dramatic decline in the number of TV sets per household, new research has shown.

According to this year's TeleScope study of the nation's viewing habits by the TV Licensing authority, the average household now has 1.83 TV sets, down from an average of 2.3 sets in 2003.

However, the good news for the TV industry is that the amount of television viewing per person across the nation is actually increasing because of the rise in online viewing and the increasing use of portable devices like iPhones.

In fact, the report shows that the average British person now watches an average of four hours and two minutes of TV a day, up from an average of three hours and 36 minutes a day in 2006.

TV Licensing said that the increasing popularity of the medium was explained partly by the growth in online viewing on laptops, tablets, and smartphones - which are now owned by 39% of UK adults , according to recent Ofcom statistics.

Following the digital switchover last year, more people are opting to use handheld devices for viewing rather than second TV sets in bedrooms, the report suggests.

However, the TeleScope study indicates that another reason for the increase in viewing time is the availability of increasingly large hi-tech flatscreen televisions as well as an increased emotional engagement with the medium.

In terms of technology, more than a third of the TV market value in 2012 was from sales of 3D TVs, and sales of large screens of 43 inches or more increased 10% in the past 12 months, the study reports. The public appetite for television is also such that we now record an estimated 455m hours, or the equivalent of almost 52,000 years of TV each year.

The TeleScope study also includes the first ever "TeleHappiness Index" survey, which seeks to assess the public's emotional engagement with television. In the findings, which surveyed more than 1,000 people, comedy is the genre which brings most happiness to viewers' lives, with 95% of those surveyed saying they got most enjoyment from the genre.

The same study also showed that 80% of people aged 65 or over found the most enjoyment in children's television, many of them watching with their grandchildren.

More than four fifths of people in Wales (82%) derive more happiness from watching sport than any other nation or region while 78% of viewers in the east of England are happier watching drama and soaps, more than everybody else, the report indicates.

Tess Alps, chair of the commercial TV marketing group Thinkbox, said the findings indicated that TV had a rosy future. She said another reason for the continued popularity of television was the increase in the calibre and choice of homegrown TV as well as the availability of quality imports from the US.

She told the Guardian: "People used to worry about the fragmentation that resulted from digital TV expansion. But this just means that there is more choice. So while 15 million people watched Coronation Street 10 years ago now 10 million do, but those 5 million are still watching TV – Stella on Sky 1, maybe or Celebrity Juice on ITV2 – and one has to assume it's something they like even better. There is great choice now."

Pipa Doubtfire, TV Licensing's head of revenue management, said: "As live viewing still represents the majority of viewing for most people, technology is being used to complement – rather than replace - 'traditional' viewing."