No....20-24 episodes! They are some series went this long..........
20-24 episodes in a single TV season? 24 weeks out of a 52-week year? I don't recall any TV season running that long in recent years; the writer's strike cut some series to only 3 episodes at the end of 2007. Now once a series is over and goes into reruns, it can play day after day for years. But I think 14 chapter/episodes would really crowd the average TV series for one year today.
For instance, the popular TV series
Moonlighting was on TV for 5 seasons from March 3, 1985 through May 14, 1989, with a total of 66 episodes shot or just a fraction more than 13 episodes per season. If as you say the first Harry Potter is 14 chapters long and you want to do one chapter of the book each episode, you couldn't quite finish shooting the first book during the first TV season of 13 weeks.
On the other hand,
The Wonder Years ran 6 TV seasons, starting jan. 31, 1988, and ending in 1993, with 115 episodes filmed, which averaged out little over 19 half-hour episodes of 22 minutes each. Could you do a Potter chapter in 22 minuets or would it need to be 40-something minutes for an hour-long program? Anyway, that rate would let you film the first book and 5 chapters of the second book but still wouldn't be enough for the later longer books of more than 20 chapters. Also,
The Wonder Years were geared to play the exact same year 20 years before each season, so 1989 was set in 1969, 1990 in 1970 and so on, so this would keep the child actors aging realistically, so that they had to finish each year within the available season so the kids would look a year older the next season. But that would mean adjusting the number of episodes to fit the TV season rather than the number of chapters per book. After all, you couldn't have one season with 14 episodes and another season that runs 25 or more.