As defined in the Code of Federal Regulations (CFR), “single package vertical air conditioner” means air-cooled commercial package air conditioning and heating equipment that:
(1) Is factory-assembled as a single package that—
(i) Has major components that are arranged vertically;
(ii) Is an encased combination of cooling and optional heating components; and
(iii) Is intended for exterior mounting on, adjacent interior to, or through an outside wall;
(2) Is powered by a single-or 3-phase current;
(3) May contain 1 or more separate indoor grilles, outdoor louvers, various ventilation options, indoor free air discharges, ductwork, well plenum, or sleeves; and
(4) Has heating components that may include electrical resistance, steam, hot water, or gas, but may not include reverse cycle refrigeration as a heating means. 10 CFR 431.92
As defined in the Code of Federal Regulations (CFR), “single package vertical heat pump” means a single package vertical air conditioner that:
(1) Uses reverse cycle refrigeration as its primary heat source; and
(2) May include secondary supplemental heating by means of electrical resistance, steam, hot water, or gas. 10 CFR 431.92
Manufacturers have been required to comply with the U.S. Department of Energy (DOE) energy conservation standards for single package vertical air conditioners and heat pumps since 2008.