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Breathe easy with better household ventilation
06/04/2025
All homes need plenty of fresh outside air to reduce moisture and ensure proper indoor air quality. Although tight, well-sealed homes are energy efficient, poor ventilation can lead to mold and mildew problems, as well as health concerns due to indoor air pollutants. A well-designed ventilation system can keep your home supplied with fresh, healthy outdoor air while minimizing energy losses.
Go natural
Although homes have been ventilated for centuries through open windows or unsealed gaps, natural or passive ventilation can also be a part of a more elaborate design approach that includes cross and convective ventilation.
In cross ventilation, a certain amount of air enters through an opening on one side of your home, while the same amount exits on the other. With convective ventilation, differences in air pressure force air through the home. The amount of fresh air depends on the placement of attic vents, solar chimneys and other ventilation devices.
Natural ventilation has limited effectiveness in cold or humid weather or in areas such as bathrooms where humidity levels can be high. Adding mechanical ventilation can help keep your home properly ventilated in these areas.
Hit the spot
Spot ventilation involves using localized exhaust fans in bathrooms or kitchens to remove moisture or pollutants at their source before they become a problem. Bathroom fans are typically ceiling-mounted, while kitchen fans are often located in the range hood.
Fans should exhaust directly outside, rather than in the attic, where they can cause moisture problems or back-draft into the home. Locate exhaust vents as far as possible from heating and cooling registers to minimize the amount of conditioned air that is exhausted with the polluted air.
Consider the whole
Whole-house ventilation systems use fans and ducts to exhaust stale air out of a home and bring fresh air in. There are four types of systems:
- Exhaust ventilation uses a central exhaust fan, typically located in the attic, to reduce the indoor air pressure and bring make-up air in through vents in the outer walls.
- Supply ventilation brings fresh air in with a fan and forces stale air out through holes or vents.
- Balanced ventilation is designed to supply and remove equal amounts of air. Air is exhausted from rooms where moisture or pollutants are generated, such as kitchens and bathrooms. Balanced systems are effective in all climates but are more expensive to install than exhaust or supply systems.
- Energy recovery ventilation (ERV) systems include fans and a heat exchanger. In winter, heat from the warm inside air is recovered to warm the cold supply air. In summer, the inside air cools the warmer supply air to reduce cooling costs. ERV systems are most effective in areas with extreme winter or summer climates.
Give your fans ENERGY STAR quality
Noise is a major reason why many homeowners avoid using ventilation fans. When purchasing a fan, select an ENERGY STAR®-qualified model. ENERGY STAR fans are certified for energy-efficient performance and must meet strict noise requirements.
