How old is my Lennox?

1. Find the rating label. Where to look on each kind of appliance.
2. Take a photo of the whole label, or note the model and serial numbers.
3. Use the lookup below. It is free, and no account is needed. A date is shown only when the available evidence supports it.

Lennox serial number: look beyond the plant code

Lennox HVAC equipment using plant/year/month serials · Sources checked October 12, 2026

In the documented Lennox numbering system, the opening characters identify the manufacturing plant. The next two digits indicate the year, followed by a month character. The first two digits therefore should not be read as the manufacture year.

Keep the full model number, including its suffix. Lennox uses model and serial information together to identify equipment and replacement parts.

This illustration applies to the documented style, not every Lennox product or era. Do not use the date on a replacement component to date the whole system.

• Lennox model and serial nomenclature: serial-numbering diagram

Lennox appliances

How to find the age, the serial number, typical life and parts for each:

• Lennox water heater (tank)8–12 yrs
• Lennox furnace15–25 yrs
• Lennox boiler15–30 yrs
• Lennox air conditioner12–17 yrs
• Lennox heat pump10–15 yrs

Alongside furnaces (including ultra-low-emission models), boilers, air conditioners, heat pumps and gas, electric and heat-pump water heaters, Lennox offers mini-splits, packaged units, air handlers, ventilation and air-quality products, and thermostats.

Lennox is the flagship brand of Lennox International, a Texas-based company that started in Iowa in 1895. It sells home furnaces, air conditioners, heat pumps, boilers and water heaters through Lennox dealers in the U.S. and Canada, and also makes commercial HVAC and refrigeration equipment.

Owned by

Lennox International

Headquarters

Richardson, Texas, USA

Founded

1895

Sister brands: Armstrong Air, Ducane, AirEase, Concord, MagicPak, Allied Air, Heatcraft Worldwide Refrigeration.

• 1895: Dave Lennox started the business in Marshalltown, Iowa.
• 1904: D.W. Norris bought the company and ran it until 1949.
• 1928: Lennox set up the Armstrong Furnace Company in Columbus, Ohio.
• 1999: Lennox International listed its shares publicly and, the same year, bought the Ducane furnace business.
• 2023: Lennox sold its European commercial HVAC and refrigeration operations.

Every Lennox check is compared with Health Canada, U.S. CPSC and U.S. NHTSA recall notices.