title: Variable-frequency drives take hold in HVAC market.
authors: P E
authors: PE
authors: Beck
mesh_terms: D000389:Air Conditioning / Q000191:economics*; D004526:Efficiency; D006361:Heating / Q000191:economics*; D008284:Maintenance and Engineering, Hospital / Q000191:economics*; D014481:United States; D014691:Ventilation / Q000191:economics*