Top 10 COMcheck Tips Every Building Designer Should Know

How to Use COMcheck for Commercial Building Energy Compliance

What COMcheck is

COMcheck is a software tool that verifies commercial building designs meet U.S. energy code requirements (e.g., IECC, ASHRAE 90.1) by checking envelope, lighting, and mechanical components against prescriptive or trade-off compliance paths.

Quick overview of the workflow

1. Choose code edition and compliance path (Prescriptive, UA Trade-off, or ERI/Performance where supported).
2. Enter project information (location, building type, gross area, design climate).
3. Define envelope assemblies (walls, roofs, windows, doors) with areas and U-factors/SHGC or insulation levels.
4. Enter HVAC system data (system type, efficiencies, capacity) and controls.
5. Input lighting power densities (LPD) and controls (occupancy sensors, daylighting).
6. Run checks and review failures; use trade-offs or adjust assemblies/systems to comply.
7. Generate and save the COMcheck report for submittal.

Step-by-step instructions (prescriptive)

1. Download and open COMcheck (desktop or web version).
2. Set project header:
   • Code version: select local adopted code (e.g., 2018 IECC).
   • Jurisdiction: pick state/city to apply amendments.
   • Compliance path: choose Prescriptive or Trade-off.
3. Enter building description:
   • Building type (occupancy classification).
   • Conditioned floor area and locations for different envelopes if needed.
4. Envelope inputs:
   • For each envelope component, enter assembly type, area, U-factor (or R-value), and SHGC for glazed elements.
   • For opaque assemblies you can enter insulation R-values or select prescriptive assemblies.
   • Ensure correct fenestration orientation and skylight data.
5. HVAC inputs:
   • Select system type from COMcheck’s list.
   • Enter efficiencies (AFUE, SEER, EER, COP) and control types (thermostat setback, economizer).
   • Include ventilation rates and heat recovery if applicable.
6. Lighting inputs:
   • Enter lighting power densities (W/ft² or W/m²) for each space or whole building.
   • Specify controls (occupancy sensors, daylight sensors, automatic shutoff).
7. Run compliance check:
   • Click “Check” to see pass/fail status for Envelope, HVAC, and Lighting.
   • Expand failed items to see required vs. provided values.
8. Fix failures:
   • Use trade-offs (e.g., improve one component to offset another) where allowed, or change assemblies/equipment to meet prescriptive limits.
   • Re-run checks until all required sections pass.
9. Generate report:
   • Export COMcheck certificate and supporting pages (PDF) for code official submittal.
   • Save the project file for revisions.

Practical tips

• Use the jurisdiction setting first—local amendments can change requirements.
• Measure and enter accurate areas and orientations; small area errors can flip results.
• When using trade-offs, prioritize low-cost envelope upgrades (better glazing, insulation) over more expensive HVAC changes.
• For complex projects, split building into multiple COMcheck projects by conditioned zoning if the code allows.
• Keep product datasheets and calculations organized to support the COMcheck inputs during inspections.

Common pitfalls

• Selecting the wrong code edition or jurisdiction.
• Entering installed equipment efficiencies instead of rated (nameplate) values.
• Forgetting to include lighting controls or daylighting reductions.
• Mislabeling conditioned vs. unconditioned spaces.

Deliverables to submit

• COMcheck compliance certificate (PDF).
• COMcheck input summary pages (showing assemblies and calculations).
• Supporting product datasheets and HVAC equipment specifications.

If you want, I can create a COMcheck-ready input checklist or a template for a specific code edition and building type — tell me the code year and building occupancy and I’ll assume reasonable defaults.