📊 Equipment Performance Data

• Source: Manufacturer published performance tables for Lennox Elite Series variable-speed air handlers (models 4024–4060)
• Data Points: CFM and motor wattage measurements at static pressures from 0.1 to 1.0 inches water column (in.wg)
• Rated BTU: Factory-certified cooling capacity at AHRI test conditions (80°F DB, 67°F WB indoor / 95°F outdoor)
• Note: Performance data represents laboratory conditions; field installations may vary based on ductwork design, installation quality, and local climate

💰 Energy Cost Calculation Assumptions

• Electricity Rate: $0.158/kWh (15.8¢) — Phoenix-area residential average as of 2024 (APS and SRP combined average)
• Baseline Runtime: 6 hours/day — typical summer daily runtime for a properly-sized system in Phoenix operating under design conditions
• Runtime Compensation Model: System runtime increases proportionally to maintain comfort when capacity drops
  • If airflow drops to 70% of baseline → system runs ~43% longer (1/0.7 = 1.43×)
  • If airflow drops to 50% of baseline → system runs ~100% longer (1/0.5 = 2.0×)
• Cost Calculation: Extra cost = (Dirty kWh/day - Clean kWh/day) × Rate
  • Clean baseline: (baselineWatts / 1000) × 6 hours
  • Dirty condition: (currentWatts / 1000) × (6 hours × runtimeFactor)

🔬 Physics & Engineering Model

• Airflow Relationship: Linear correlation between CFM and delivered cooling capacity (BTU ∝ CFM)
• Static Pressure: Direct measurement of system resistance; increases as filters/coils load with particulate matter
• Fan Laws: Motor power increases with static pressure as blower works harder against restriction
• Capacity Loss: (1 - currentCFM/baselineCFM) × 100%
• Delivered Tonnage: (deliveredBTU / 12,000) — industry standard conversion
• Blower Animation: Rotational speed decreases with increasing static pressure load (visual representation of fan curve behavior)

⚠️ Limitations & Disclaimers

• Simulation Scope: This tool models indoor blower motor energy only; does not include compressor, auxiliary heat, or controls
• Regional Variance: Electricity rates vary significantly by utility provider and rate plan; actual costs may differ
• Usage Patterns: Actual runtime depends on thermostat setpoint, occupancy behavior, insulation quality, and outdoor temperature extremes
• Maintenance Status: Assumes factory-fresh condition at 0.1 in.wg; actual "clean" baseline may vary based on ductwork design
• System Sizing: Cost impacts scale with system size; larger systems (4-5 ton) consume more energy than smaller units (2-2.5 ton)