
HVAC Load Calculation Analyzer
Calculate HVAC heating/cooling loads with equipment sizing and code compliance
What You Can Do
Process building data through a structured analytical framework to develop defensible heating and cooling load estimates that meet ASHRAE and ACCA standards. You'll generate equipment sizing recommendations (furnace, AC, heat pump, boiler capacity), calculate ductwork and diffuser requirements, and produce documentation suitable for permit submissions and contractor bids. The skill handles single-zone and multi-zone projects with climate-specific parameters across residential and commercial applications.
Features
Applies ASHRAE design conditions, solar heat gain factors, and regional weather data to your building location
Calculates BTU/h requirements and suggests furnace, air conditioner, heat pump, or boiler capacity with efficiency ratings
Converts load estimates to design airflow (CFM) and recommends duct sizing and diffuser placement by zone
Cross-checks calculations against ACCA standards and flags design parameters for code approval
Handles residential and commercial projects with separate load calculations per zone or floor
Evaluates walls, windows, roof, foundation thermal resistance and air leakage impact on loads
Produces justification summaries and calculation sheets suitable for permit applications
Compares sizing and operational costs across different efficiency ratings and equipment types
Example Output
Example 1: Residential Load Calculation
- Sensible Heating Load: 42,500 BTU/h | Sensible Cooling Load: 38,200 BTU/h
- Recommended Equipment: 4-ton AC unit (48,000 BTU/h) + 50,000 BTU/h furnace (AFUE 95%)
- Ductwork: 1,600 CFM return + 1,400 CFM supply; 8" main duct, 6" branch ducts
- Compliance: ✓ ASHRAE 90.1 compliant | ✓ Local code verified
Example 2: Commercial Multi-Zone Load
- Floor 1 (Office): 125,000 BTU/h cooling | 95,000 BTU/h heating
- Floor 2 (Lab with higher internal gains): 165,000 BTU/h cooling | 78,000 BTU/h heating
- Total System: Dual 10-ton units recommended with VAV distribution
- Critical Design Notes: Lab zone requires 1.5× safety factor; north facade has minimal solar gain
What's Included
- SKILL.md instruction file: Complete framework for load calculation analysis
- Building Data Template: Structured checklist for collecting building dimensions, envelope properties, window specifications, and occupancy data
- Load Calculation Worksheet: Step-by-step calculation breakdown showing heating/cooling load by component (transmission, infiltration, solar, internal gains)
- Equipment Sizing Reference Chart: Quick-lookup table correlating BTU/h loads to furnace, AC, and heat pump capacities across efficiency tiers
- Code Compliance Checklist: Verification points for ASHRAE 90.1, ACCA Manual J, and local mechanical code requirements
Who It's For
- HVAC design engineers — Develop load calculations for new construction and renovation projects
- MEP consultants — Support mechanical design phases on commercial and institutional buildings
- HVAC contractors — Size equipment and justify system specifications for bids and proposals
- Mechanical code officials — Verify design loads and equipment adequacy during permit review
- Facilities managers — Evaluate whether existing equipment is adequate after building modifications or envelope improvements
Best For
- Preliminary and detailed HVAC design for residential homes and small commercial buildings
- Equipment sizing and selection across furnaces, air conditioners, heat pumps, and boiler systems
- Ductwork and diffuser layout planning based on room-by-room load distribution
- Design justification documents for mechanical code compliance and permit applications
- Comparison analysis of equipment efficiency ratings and life-cycle operational costs







