What is required for energy efficient homes to maintain consistent indoor air quality?

Maintaining consistent indoor air quality in energy-efficient homes is primarily dependent on ensuring a constant supply of fresh air. In such homes, airtight construction methods are commonly used to enhance energy efficiency. This can inadvertently limit natural ventilation, leading to potential indoor air quality issues if fresh air isn't regularly introduced.

By providing a continuous supply of fresh air, homes can effectively dilute indoor pollutants, control humidity levels, and ensure that occupants have a healthy environment. This can be achieved through mechanical ventilation systems designed to bring in outdoor air while minimizing energy loss, as well as using balanced ventilation systems that exchange stale indoor air for fresh outdoor air.

The other options, while they can contribute to overall comfort or air quality in specific contexts, do not provide the necessary systematic solution for ensuring consistent indoor air quality in energy-efficient homes. Regular air filter changes primarily improve the efficiency of existing ventilation and filtration systems, but without a consistent influx of fresh air, indoor air quality may still suffer. Opening windows can help, but it may not be practical or efficient in all situations, especially in climates where outdoor conditions can adversely affect indoor air quality. Ceiling fans aid in air circulation, which can enhance comfort, but they do not introduce new fresh air into the home.