In the recent past, a mechanical contractor could install very inefficient appliances and equipment with no thought to energy costs. Energy rates were cheap; therefore, mechanical codes did not address energy usage. Mechanical code emphasis was on installation integrity, clearance to combustibles, and service space requirements. The installed equipment was very heavy and overbuilt. That all changed in the late 20th century due to several economic and environmental factors. These factors created a new buzzword: energy conservation.
Don't wait to let the Electrical Inspector teach you the new 2023 NEC. Save time, save money,
and pass inspections the first time by completing your continuing education requirements.