ACCA Manual S – Residential Equipment Selection

For years, many have believed that residential HVAC equipment selection was based only on the Air Conditioning Contractors of America (ACCA) Manual J. In other words, a Manual J cooling load of 30,000 BTU/h would require a 2.5-ton air conditioner, correct?

ACCA Manual S is an ANSI standard, providing guidance for interpreting and applying original equipment manufacturers’ (OEM) expanded performance data. Manual S is used to correctly select equipment that meets the system requirements, based on the design conditions used for calculating the loads. They include:

• Heating
• Sensible cooling
• Latent cooling

ACCA Manual S sets equipment sizing limits to ensure equipment capacities maintain your customers comfort while preventing the problems associated with over or under sizing equipment. These issues include:

• Health issues associated with excessive humidity
• Larger energy consumption
• Callbacks from comfort complaints
• Greater wear and tear on the equipment^,
• Higher, upfront construction costs (larger equipment is more expensive)

ACCA Manuals J and S must be performed on and submitted for every home per the Mechanical Section of the 2015 International Residential Code (IRC):

For more information, download the ACCA Manual S Brochure, which includes a checklist.

Our staff at Enerlogic would be happy to assist you with all of your ACCA Manual J load calculation and ACCA Manual S equipment selection questions and provide both design and installation verification services in a timely manner.