The usual rule for the maximum size of TV screen that can be used in any room is to have a screen three to six times smaller than the distance of the viewer from the TV.
However a high definition screen, with very high resolution enables a viewer to sit much closer to the television and there is a growing evidence amongst reviews and internet blogs that many regret the size of their new TV being too small, shortly after about getting it.
Here’s a standard guideline of the minimum distance to be maintained to accommodate the maximum size of the television:
Maximum screen size of HDTV Viewing Distance
34 inches 52 inches
44 inches 68 inches
52 inches 88 inches
72 inches 108 inches
Another rule of thumb is to sit in your armchair / sofa and place a wide object in the space where you intend to have your new TV. Then ask someone to mark the left and right extremities of the area you can view without moving your eyes or head. That screen size should generally work well for a HDTV.
Of course many transmissions are not yet in high definition, so the compromise solution may well be to choose a screen size somewhere between the larger sizes that the new rules will come up with and the old one of up to 3 to 6 times smaller than the viewing distance.