Last week in Phoenix, a 3‑ton 16 SEER heat pump with 0.95 in. w.c. ESP and about 20% leakage to outdoors at 25 Pa modeled 11–14% higher kWh than a 14 SEER with tight, low‑static ducts; have you seen the same crossover where airflow losses erase nameplate efficiency? I’m prioritizing duct sealing/resizing before equipment swaps because the payback keeps landing under 2 years in my audits.