Day & Night heat pumps are manufactured by International Comfort Products, a subsidiary of the Carrier heating and air conditioning group. In addition to Day & Night, ICP also owns the Heil and Tempstar brands and produces heat pumps under those names as well.
Day & Night began as a solar water heater company in California in 1909, not entering the space heating arena until the 1930s. The brand was discontinued in 1997, but was brought back in 2009. The Day & Night heat pump product line is essentially identical to that of sister brands Tempstar and Heil. As of 2015, ICP manufactures products for these brands in factories located in Mexico, Canada and the United States.