The obvious answer is 'yes' just because you'll no longer feel the drafts that result from cold air entering through low-quality windows. There's actually much more to an improved comfort level though. First off the insulation around your windows and doors is replaced with insulating foam which fills every void that might have been present resulting in more drafts. Window upgrades also keep your home more comfortable in the summer by
retaining cooled air and help to control indoor humidity throughout the year.