Fortunately, making your home more energy efficient isn't rocket science. To save energy immediately, begin by sealing the gaps that lead from your living areas to the attic. Some of these gaps accommodate wiring and pipes, while others result from poor craftsmanship and the normal settling of the building. But all of them serve as passageways for heated air to escape. That's because houses act like big chimneys.
Warm air rises to top of the building, increasing air pressure near the ceiling.
The difference between that pressure and the lower pressure outside on a cold day drives the warm air through any crack, crevice or gap it can find. The high pressure at the top also creates low pressure near the bottom of the house, which pulls cold air in through openings around the foundation or slab. Energy experts call this the stack effect. The larger the spread between inside and outside temperatures, the greater the pressure differences and the stronger its pull. However, if you have mold or condensation problems in your home during winter, don't do any sealing until you've tackled the moisture situation.