ACCA Manual J: HVAC Residential Calculation 8th
Manual J is the industry standard residential load calculation method, required by most building codes around the country. Revised and expanded, this Eighth Edition procedures produce improved equipment sizing loads for single-family detached homes, small multi-unit structures, condominiums, town houses and manufactured homes.
These procedures are also compatible with different types of comfort systems and applications such as:
- A central single-zone comfort system
- A central multi-zone system
- A distributed multi-zone system
- Dwellings that have limited exposure or no exposure diversity
MJ8 also accommodates homes that have exceptional architectural features and life style accessories such as:
- Homes with large south-facing glass area or rooms with unusually large glass area
- A thermally isolated solarium
- Customized internal load estimates
MJ8 is sensitive to an increased variety of issues related to construction materials and methods including:
- Fenestration loads for glass rated by the National Fenestration Rating Council (NFRC)
- Improved duct load models
- Improved methods for estimation the effect of internal and external shading devices, including insect screens
- Infiltration estimated based on blower door test
- Sensitivity to latitude and altitude
- Sensitivity to skylight to roofing material, curb construction and light shaft construction
- Heat loss and gain for log walls, structural foam panels, aerated autoclaved concrete block, insulated form concrete panels, brick walls, concrete walls, wood foundation walls, and many other types of walls and insulation options
The recently released Eighth Edition of Manual J is a significant expansion over the Seventh Edition. There are numerous changes, but the most noticeable is a much larger list of built-in floor, roof, wall, glass and door materials.
The Seventh Edition was also missing references to current popular materials such as structurally insulated panels, insulated concrete forms, logs, and much more. The Eighth Edition includes all these materials plus all common building materials with hundreds of variations.