Lennox® HVAC age

How to determine the date of production/manufacture or age of Lennox® brand HVAC Systems.

The industry average service design life for most forced air furnaces is 15-20 years, and the industry average service design life for most air conditioning condensing units is 10-15 years. The average service design life of boilers can vary from as little as 10 years to as many as 50 years depending on the type and quality of materials used in their manufacture. Routine upkeep/maintenance, regional weather/climate, and location/placement of the mechanical systems will all play critical roles in the longevity of these systems.

Parent Company: Lennox International

The date of production/manufacture or age of Lennox brand HVAC equipment can be determined from the ten character serial number located on the rating data plate.

Example serial number styles/formats found:

Style 1: 1606B13871 -or- 5899L17212 (1973 and after)
Style 2: 724 -or- 6512 (prior to 1973)

Legend: Year is RED; Month is GREEN; Week is BLUE

Style 1: 1606B13871 -or- 5899L17212 (Style used 1973 and after)

The first two digits of the serial number are the Factory or Plant Code.

Year of manufacture can be determined by using the 3^rd & 4^th positions of the serial number

Month of manufacture can be determined by using the 5^th position (letter) of the serial number

This style of serial number has been used exclusively since 1973.

Style 2: 724 -or- 6512 (Style used prior to 1973)

Year of manufacture can be determined by using the 1^st & 2^nd positions of the serial number

Month of manufacture can be determined by using the 3^rd -or- 3^rd & 4^th position(s) of the serial number (months 1 through 12)

This style of serial number was used prior to 1973.

Brand® History¹

1895 – Lennox founded in Marshalltwon, Iowa by Dave Lennox - builds and markets the industries first riveted steel furnace.
1904 - Dave Lennox sells business to D.W. Norris, who incorporated the business as Lennox Furnace Company and proceeds to sell 600 furnaces in the company's first year.
1923 - Lennox expands to Syracuse, New York
1920's - Lennox acquires Armstrong.
1935 - Lennox pioneers the introduction of a forced-air furnace for residential heating.
1943 - Lennox provides heating equipment for the military effort, as well as builds parts for military aircraft and bombs.
1952 – Lennox establishes operations in Canada.
1950's - Lennox sells Armstrong
1955 - Changes name from Lennox Furnace Company to Lennox Industries, Inc.
1965 - Lennox manufactures first commercial packaged direct multi-zone rooftop unit for heating and cooling.
1973 - Lennox acquires Heatcraft from PEP Industries, including the Larkin, Bohn, Chandler, and Climate Control brands.
1982 - Lennox develops and manufactures the industry's first high-efficiency gas furnaces - The G14 Pulse furnace.
1986 – Lennox International Inc. is established as the parent company for formed as the parent company for Lennox Industries and Heatcraft.
1986 - Heatcraft acquired the Grenada, Mississippi, coil manufacturing and copper mill facility of SnyderGeneral Corp.
1988 - Heatcraft acquired another of SnyderGeneral's facilities, a refrigeration products manufacturing plant in Wilmington, North Carolina.
1988 – Lennox establishes Heatcraft, Inc.
1988 - Lennox re-acquires Armstrong Air Conditioning, Inc.
- Armstrong was purchased by Johnson Corporation in 1962, which was in turn acquired by Magic Chef in 1971. Magic Chef became a division of Maytag in 1986, and its name was lengthened to Magic Chef Air Conditioning. It was this division that Lennox International purchased from Maytag in 1988 and subsequently renamed Armstrong Air Conditioning Inc.
1991 - Lennox establishes world headquarters in Dallas, Texas.
1994 - Lennox introduces CompleteHeat™, the first combination space and hot-water high-efficiency heating system by a major HVAC manufacturer.
1995 – Lennox Global Ltd. Is established.

¹Excerpts from https://www.referenceforbusiness.com/history2/32/Lennox-International-Inc.html & https://www.lennoxinternational.com/about/history/

Every effort is undertaken to offer you correct and concise information to assist you in determining the age or manufacture date of HVAC/R equipment. Users relying on this information do so at their own risk.

Page last updated: 08/21/2023

Any of the trademarks, service marks, collective marks, design rights or similar rights that are mentioned, used or cited in the articles of the Building Intelligence Center (www.building-center.org) are the property of their respective owners. Their use here does not imply that you may use them for any purpose other than for the same or a similar informational use as contemplated by the original authors of these articles under the CC-BY-SA and GFDL licensing schemes. Unless otherwise stated Building Intelligence Center (www.building-center.org) sites are neither endorsed by nor affiliated with any of the holders of any such rights and as such Building Intelligence Center (www.building-center.org) cannot grant any rights to use any otherwise protected materials. Your use of any such or similar incorporeal property is at your own risk. This guide is intended to assist Commercial/Residential Building Inspectors, HVAC professionals, Facilities Managers, HOA’s, etc.., in determining the date of manufacture and/or age of HVAC equipment to determine the expected useful life (EUL). This web site should not be relied upon for commercial use or interpretations. Accuracy and reliability of the information provided is believed accurate but is not guaranteed. The burden for fitness of information provided relies solely and completely with the user. In no event will Building Intelligence Center or its representatives be liable for any loss or damages whatsoever for consequential, incidental, indirect, special, or tort damages of any kind, including but not limited to loss of data, lost profits, business interruption, loss of business information, or other pecuniary loss that might arise from the use of or reliance on the information provided within.

Lennox®

How to determine the date of production/manufacture or age of Lennox® HVAC Systems.

The date of production/manufacture or age of Lennox® HVAC equipment can be determined from the serial number located on the data plate.