The Broan FT4BI iQ Drive® heat pump uses inverter-driven rotary compressor technology. The compressor can ramp down to 900 rpm for ultra-low power operation and an ultra-low noise level, making for a quieter home, especially at night. The inverter has almost infinite modulation for a perfectly even variance, says the company, and runs as low as 15 Hz. It alters the compressor speed just enough to match the slightest change in air temperature. The heat pump can modulate between 40-118 percent of capacity, instantly adjusting to offset the cooling and heating demands on the home. It is rated up to 22 SEER and an HSPF up to 10 for efficiency and as low as 59 dB for sound.

Nordyne, St. Louis, MO; or

eProduct 185