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Over 100 years of HVAC innovation with strong U.S. market presence
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Premium Infinity® series known for variable-speed precision and high efficiency
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Broad product range across furnaces, air conditioners, and heat pumps
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Excellent humidity and temperature control in variable climates
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Reliable build quality with corrosion-resistant components
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Industry-recognized for quiet operation and advanced connectivity

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A97MV Modulating Gas Furnace with 97% AFUE and variable-speed ECM blower
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SCU23LX Air Conditioner featuring inverter-driven performance and up to 23 SEER2
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4SHP23LX Heat Pump with up to 23 SEER2 and 10.5 HSPF2 for year-round efficiency
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Comfort Sync® A3 thermostat compatibility for smart zoning and mobile control
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EHX™ Technology in furnaces ensures even heat and reduces hot spots
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Backed by Allied Air Enterprises (a Lennox International company) with strong dealer support
Carrier HVAC
Founded in 1902 by Willis Carrier - the man credited with inventing modern air conditioning - Carrier is one of the most recognized HVAC names worldwide. In my years working with residential ducted systems, Carrier has consistently delivered a balance of innovation, comfort, and durability. The Infinity® series is their flagship line, offering top-tier performance with advanced control systems, variable-speed technology, and strong energy efficiency.
For this review, I’m focusing on three standout products that represent Carrier’s engineering strengths in each major residential ducted category:
- Infinity® 98 Gas Furnace with Greenspeed® Intelligence (59MN7) – Carrier’s most advanced furnace for precise heating.
- Infinity® 26 Air Conditioner (24VNA6) – a flagship AC designed for superior cooling and humidity control.
- Infinity® 24 Heat Pump with Greenspeed® Intelligence (25VNA4) – a versatile year-round option for both heating and cooling.
These units are selected not just for their place at the top of the spec sheet, but because they’ve proven themselves in actual homes, backed by both my field experience and consistent customer feedback.
Armstrong Air HVAC
Armstrong Air may not have the same name recognition as others, but among contractors, it’s known as a premium, professional-grade brand that combines Lennox engineering with its own innovations. Manufactured under Allied Air Enterprises, Armstrong Air benefits from Lennox’s R&D resources while carving out a niche as a contractor-preferred brand with strong support and durable products.
For this review, I’m focusing on three flagship products: the A97MV Modulating Gas Furnace, the SCU23LX Air Conditioner, and the 4SHP23LX Heat Pump. Together, they represent Armstrong Air’s top-end lineup, showcasing high efficiency, inverter-driven technology, and smart control integration. In my field experience, it appeals most to homeowners who rely heavily on contractor recommendations and want premium comfort without the marketing markup of more famous brands.