Carrier says that within their Infinity line of gas furnaces, you can find the most efficient, and the quietest gas furnace money can buy. We can't say as to whether the quietest claim is true -- furnaces operate at difference fan frequencies and burner modulation, which affects the noise. So comparing furnace noise is tough. However, the 98.5% AFUE is definitely the industry leader for efficiency.
Infinity 59MN7 Gas Furnace -- Greenspeed
The Carrier Infinity furnace features their Greenspeed technology. Greenspeed is a way for certain Carrier equipment to communicate with each other for fine tuning performance and efficiency. See the Green Speed page for additional information.
Carrier claims that this furnace is the quietest furnace money can buy. However Lennox makes this claim with their SLP98V furnace. Since there are no official industry standards to measure the sound decibals of a modulating, variable speed furnaces, this is up for grabs. However, hats off to Carrier for at least coming up with an online tool: furnace sound comparison.
Key Performance & Efficiency Features
Below are some of the features of the Carrier Infinity 59MN7 gas furnace:
Up to 98.5% AFUE heating efficiency
Greenspeed intelligence for ideal comfort and energy savings
Precise modulating gas valve capable of matching the heating needs of the home
Variable-speed, ECM blower motor for ultimate comfort and ultra-quiet operation
Ideal Humidity System® technology capable to aid heat pump or air conditioner summer dehumification
SmartEvap technology works in concert with your cooling system to aid summer dehumidification
ComfortFan technology allows fan-speed choices in "Constant ON" mode
10-year parts limited warranty
Lifetime heat exchanger limited warranty
Load matching performance delivers just the amount of heat needed for longer, quieter run times while minimizing energy use.
The quietest furnace you can buy (060V17-14 model/size)
The most efficient furnace you can buy (060V21-20 model/size)
Best temperature control management among Carrier® furnaces
Hybrid Heat® compatible
Can help boost cooling SEER efficiency when matched with appropriate cooling system components
In zoned systems improves airflow control for greater comfort and quiet