Armstrong Air / AirEase / Concord / Allied heating and cooling equipment carry the build date inside the serial number. We know 3 serial formats for this brand; the decoder tries each one and shows every reading that fits.
The first two digits are the factory, not the date. The next two digits are the year and the letter after them is the month (A is January, M is December, I is skipped).
4607B20058 reads as February 2007.
Two sources agree Building Intelligence Center, McGarry and Madsen Home Inspection, InterNACHI inspector forum, Energy Trust of Oregon furnace chart
On ten-digit all-number serials the seventh and eighth digits are the year and the last two are the week.
4140720328 reads as week 28 of 2003.
Two sources agree Building Intelligence Center, McGarry and Madsen Home Inspection, Energy Trust of Oregon furnace chart, PickHVAC
The seventh character is the month letter and the eighth is the year code (8 and 9 for 1978 and 1979, then A for 1980 through N for 1992).
A10322EDB reads as May 1983.
Two sources agree InterNACHI inspector forum, McGarry and Madsen Home Inspection
A gas furnace usually lasts 15 to 20 years. Well-maintained units in mild climates reach 25; units that run hard with dirty filters fail sooner.
How long does a furnace last? · Should I replace my furnace? · HVAC.com, Lennox, InterNACHI (15-25)
A central AC condenser usually lasts 12 to 15 years. In hot climates where it runs most of the year, 10 is more typical; in the north, 20 is possible.
How long does a central air conditioner last? · Should I replace my air conditioner? · Bryant, Lennox, InterNACHI (7-15)
An air-source heat pump usually lasts 10 to 15 years. It runs in both seasons, so it logs more hours than a furnace or an AC alone.
How long does a heat pump last? · Should I replace my furnace? · Trane, Lennox, Bryant, InterNACHI
Should I replace my furnace? · Should I replace my air conditioner?
Goodman · Amana (heating and cooling) · Daikin · Carrier · Bryant · Payne · Day & Night · Heil / Tempstar / Comfortmaker / Arcoaire / KeepRite · Lennox · Ducane · Aire-Flo · Trane · American Standard (heating and cooling) · York · Luxaire · Coleman / Evcon · Fraser-Johnston / Champion / Guardian · WeatherKing · Nordyne / Intertherm / Miller / Maytag / Frigidaire / Tappan / Westinghouse / Kelvinator / Gibson / Broan · Comfort-Aire / Heat Controller / Century
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Galvanized, polybutylene, cast iron and the sewer line: what fails, what it costs, what insurance won't cover and how to decide.
A buyer's guide to older homes: wiring, pipes, lead, asbestos, insurance refusals and what the repairs actually cost.
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