Manual S – Residential Equipment Selection

Manual S provides procedures for selecting and sizing residential HVAC equipment based on specific design conditions, including local climate and home construction characteristics. It emphasizes the importance of matching equipment capacities to the calculated heating and cooling loads to prevent issues such as short cycling, excessive humidity, and increased energy consumption.

Key Aspects:

• Comprehensive performance data compared with ARI direc­tory data for air conditioners and heat pumps, and the presentation formats used by different manufacturers.
• How ventilation loads and air distribution system loads affect equipment size and performance.
• How to determine the condition of the air approaching the cooling coil when outdoor air is introduced into the return side of the duct system, including specific tables and charts.
• Cooling-only equipment, air-to-air heat pumps, water-to-air heat pumps, dual fuel heat pumps, multispeed and variable speed equipment.
• Why the “400 CFM per ton rule” is a myth, why the blower CFM is exclusively defined by the sensible heat equation, why lower DX coil air flow rates are compat­ible with humid climates, and why water source refrig­eration cycle equipment should not be sized to satisfy the design heating load.

Highlights:

• Expanded Equipment Coverage: The 2023 edition includes guidance for a broader range of equipment types, accommodating the industry’s shift towards electrification and variable-capacity systems.
  
• Variable-Capacity Equipment Guidance: Recognizing the increased use of variable-capacity equipment, the standard provides expanded guidance to ensure proper selection and sizing.
  
• Code Compliance Support: Manual S assists in demonstrating compliance with the International Residential Code (IRC) and the Uniform Mechanical Code, providing minimum documentation requirements.
  
• Dehumidification and Humidification: The manual offers expanded guidance on the use of dehumidifiers and humidifiers to improve indoor air quality and comfort.

About ACCA

The Air Conditioning Contractors of America (ACCA), a leading trade association for HVAC professionals in the United States. While specific individual authors are not publicly credited, the manual is developed by a committee of industry experts, engineers, and professionals with extensive experience in HVAC system design. These contributors work collaboratively to ensure the manual reflects current industry practices, standards, and technological advancements.

Other Works:

• Manual D – Residential Duct Systems