Ventilation is the least expensive and most energy-efficient way to cool buildings. Ventilation works best when combined with methods to avoid heat buildup in your home. In some cases, natural ventilation will suffice for cooling, although it usually needs to be supplemented with spot ventilation, ceiling fans, and window fans. For large homes, homeowners might want to investigate whole house fans.
Interior ventilation is ineffective in hot, humid climates where temperature swings between day and night are small. In these climates, natural ventilation of your attic (often required by building codes) will help to reduce your use of air conditioning, and attic fans may also prove beneficial. However, an alternate approach is to seal the attic and make it part of the conditioned space in your house, putting the insulation on the inside of the roof rather than on the floor of the attic. Sealed attics are more feasible in new home construction, but can be retrofitted on an existing house.
This is a repost from EERE Energy Savers. Read the full article