Final answer:
The estimated life span and efficiency data on equipment are usually provided by the U.S. Energy Information Administration (EIA) or similar bodies that produce detailed statistics and reviews, employing measures like the EER and SEER.
Step-by-step explanation:
Normally, the estimated life span and efficiency data on equipment are provided by organizations responsible for comprehensive reviews and reporting on energy information, such as the U.S. Energy Information Administration (EIA) and independent research bodies. These organizations compile data from various sources, examining the efficiency and longevity of equipment through annual surveys, reviews such as the Annual Energy Review, and monthly statistics reports like the Electric Power Monthly. Additionally, they might employ measures such as the energy efficiency ratio (EER), seasonal EER (SEER), and Heating Seasonal Performance Factor (HSPF) to estimate equipment efficiency over different seasons.