GREENGUARD Gold: what the certification means

Volatile organic compounds, or VOCs, are chemicals that are emitted as gases from certain solids and liquids. The EPA says concentrations of many VOCs are consistently higher indoors than outdoors, up to ten times higher, and furniture and building materials are among the sources.

GREENGUARD testing puts the finished product in a sealed, temperature and humidity controlled chamber and measures what comes off it. UL says its chambers range from the size of a small oven to a full room that can hold a crib or a queen-size mattress, and that items such as furniture can sit in a chamber for up to two weeks.

The result is a statement about air, not about contents. A product passes because its measured emissions are under the limits. Nothing in the test asks whether the foam is polyurethane or latex, or whether the cotton is organic.

Both tiers are based on the UL 2818 standard for chemical emissions from building materials, finishes and furnishings. UL's public pages describe the difference in general terms, shown below. The numeric limits themselves sit in UL 2818, which UL sells as a standard document, so we do not print figures here.

UL Solutions owns the program outright. It states that it is the only owner, operator and issuer of GREENGUARD certification and marks, and it runs the test laboratories. So the standard setter and the tester are the same company, which is worth knowing when you weigh the mark.

UL says all certified products are subject to a review of the manufacturing process and routine testing, and that once an item is certified a new version of it is retested each year. Certification from start to finish takes about one to six months.

The organic labels work from the other end. GOTS certifies that a textile contains organic fiber and was processed under set chemical and social rules. MADE SAFE reviews the ingredients and materials themselves. GREENGUARD Gold looks only at what reaches the air.

That makes them complementary. An organic crib mattress can carry GOTS for its cotton and GREENGUARD Gold for its emissions. Nothing in the program requires organic material, so a conventional mattress can qualify too. If a page lists GREENGUARD Gold under "organic certifications", that is a mislabel.

UL lists mattresses, furniture, flooring, building materials, electronics, cleaning products and children's and baby products among the certified groups. For this site it matters most on cribs and nursery furniture, sofas and furniture and adult mattresses: large items made with glues, finishes and foams, in rooms where people sleep.

Use it as one check among several. It answers the air question well. Pair it with a materials or ingredient label for the contents, and with ventilation, which our indoor air quality guide covers.