Size and select all HVAC equipment in accordance with ACCA Manuals J and S. Load calculation must coordinate with accurate construction specifications and plans for the project as well as as-built conditions.
Complete load calculation with accredited ACCA Manual J 8th Edition Software or stamp by a Professional Engineer
Load calculation must be based on ACCA Manual J 8th Edition Software. The following software programs are ACCA Manual J 8th Edition compliant:
- Wrightsoft Right-J8
- Elite RHVAC
- Nitek HVAC Wizard
- Adtek AccuLoads
- Florida Solar Energy Center‘s EnergyGauge
Load calculation must be stamped by a Professional Engineer along with a signed "Professional Engineer Load Calculation Affidavit". This can be found on the EarthCraft website under Resources.
Base on worst-case unit orientation
Load calculation must be based on worst-case unit orientation as constructed.
Use 2009 ASHRAE Handbook of Fundamentals Climate Design Information for outdoor design temperatures
Design heating and cooling systems using the annual outdoor design conditions as defined in the 2009 ASHRAE Handbook of Fundamentals, Chapter 14.
- The 99% design conditions must be used to size heating equipment
- The 1% design conditions must be used to size cooling equipment
Indoor temperatures 70°F for heating and 75°F for cooling
Design heating and cooling systems using indoor design temperatures of 70°F for heating and 75°F for cooling.
Base infiltration on "average"
Select "average" or software equivalent for whole house infiltration.
Use actual area, U-factor and SHGC for windows and doors, actual area and R-values of floors, walls and ceilings
Load calculation must be based on actual window, insulation and door specifications as installed. Window, door, wall, floor and ceiling areas must be ±10% of actual areas as constructed.
Base on ASHRAE 62.2 ventilation loads
Load calculation must be based on ventilation system designed and installed to meet ASHRAE 62.2-2007. This includes the ventilation system type, location, design rate, and frequency and duration of each ventilation cycle.
Cooling equipment and/or single-stage heat pump between 95-115% (≤125% for heat pump in Climate Zone 4)
Cooling equipment selection must be between 95-115% of load calculation or the next available size unit. Installed heat pumps in Climate Zone 4 must be within 125% of load calculation or the next available size unit.
The abridged edition of ACCA Manual J is not an acceptable methodology within the EarthCraft program.
If software allows for grades of duct tightness, chooses "extreme" or the equivalent term.