Last year, a study by the National Center for Healthy Housing (NCHH) found that 35 million—or 40 percent—of metropolitan U.S. homes have one or more health and safety hazards present. What's more, progress on reducing these exposures is not improving as the number of homes with substandard conditions—6.3 million units in the U.S.—did not decrease from 2001 to 2011. Between 20 and 30 percent of asthma cases are linked to home environmental conditions and more than 24 million homes have lead-based paint hazards in place.

"The consequences of not dealing with substandard housing are dire in both human well-being and cost," says Georges Benjamin, executive director of the American Public Health Association (APHA). "In many communities, housing regulations have neither kept pace with the way Americans interact with their homes nor with the modern diseases that plague society—including chronic diseases such as asthma and depression, cancer, and certain injuries."

Aiming to improve the health and safety of existing homes in the U.S., NCHH and APHA today released the National Healthy Housing Standard, which provides recommendations for the maintenance and condition of occupied dwellings. In full disclosure, I am a member of the standard's corporate advisory board.

The standard's authors focus on the country's 100 million existing homes because "the new construction market remains a fraction of the overall housing stock in the country," they write. "In contrast, regulations and industry practices affecting existing owner-occupied and rental housing, the focus of this document, have not kept pace with our knowledge about housing-related disease and prevention of disease and injury through routine maintenance."

The standard's provisions aim to fill gaps where there are no property maintenance policies and to complement the International Property Maintenance Code and other federal, state, and local policies in place regarding the upkeep of existing homes. The standard is designed as a property maintenance policy, not a building code, NCHH executive director Rebecca Morley noted during a lunch announcing the standard. Its recommendations, which are meant to constitute a set of minimum performance standards, are divided into seven chapters: owner and occupant duties; structures, facilities, plumbing and space requirements; safety and personal security; lighting and electrical systems; thermal comfort, ventilation and energy efficiency; moisture control, solid waste, and pest management; and chemical and radiological agents. Each section includes stretch measures for those who may seek to go beyond the minimum requirements. The goal, Morley said, was to keep homes "dry, clean, pest-free, contaminant-free, ventilated, safe, and maintained."

A number of provisions feature elements that will be familiar to high-performance builders. Every habitable room should receive daylight from at least one exterior window or skylight, for example, and building materials used in maintenance and renovation should be no- or low-VOC and have no halogenated flame retardants. Building science references to elements such as air sealing, ventilation, and water management are also present throughout the standard, which advocates for high-quality construction and system installation.

Click here to read the full standard, along with the rationale and research behind each of its provisions.