Ruud water heaters carry the build date inside the serial number. We know 5 serial formats for this brand; the decoder tries each one and shows every reading that fits.
Skip any letters at the start. The first two digits are the month and the next two are the year. If the first two digits are 13 or higher they are the week instead.
RU0904B21710 reads as September 2004.
Two sources agree Building Intelligence Center, InterNACHI water heater dating chart, InspectAPedia, Energy Trust of Oregon serial charts
Find the single letter in the middle of the serial (often F, M, G, N or W). The two digits after it are the week and the next two are the year.
CB5D302F099903346 reads as week 9 of 1999.
Two sources agree Building Intelligence Center, PickHVAC, Energy Trust of Oregon furnace chart, InterNACHI inspector forum
On nine-digit serials the last two digits are the year and the two before them are the week.
123451872 reads as week 18 of 1972.
Two sources agree Building Intelligence Center, PickHVAC, Energy Trust of Oregon furnace chart
On tankless units with a period in the serial, one source reads the two digits before the period as the year and the two after as the month.
05.05-000021 reads as May 2005.
One source Building Intelligence Center
Another source reads the two digits before the period as the month and the two after as the year.
05.05-000021 reads as May 2005.
One source InspectAPedia
A standard tank water heater usually lasts 8 to 12 years. Some make it to 15 with soft water and a replaced anode rod; some fail at 7.
How long does a tank water heater last? · Should I replace my water heater? · DC Dept. of Energy & Environment, InterNACHI
A gas tankless water heater usually lasts 15 to 20 years, and sometimes longer, because there is no tank to rust through. Scale buildup in the heat exchanger is what shortens its life.
How long does a tankless water heater last? · Should I replace my water heater? · DC Dept. of Energy & Environment, U.S. DOE Building America
A heat pump (hybrid) water heater is expected to last 10 to 15 years. ENERGY STAR bases its savings math on 13 years.
How long does a heat pump water heater last? · Should I replace my water heater? · DC Dept. of Energy & Environment, ENERGY STAR (13-year basis)
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 water heater? · Should I replace my furnace? · Should I replace my air conditioner?
A.O. Smith · American Water Heater · U.S. Craftmaster · Bradford White · State · Reliance · Kenmore · Whirlpool · Rheem · Richmond · GE · Marathon · Rinnai · Navien · Noritz · Takagi · Bosch (tankless water heater) · Lochinvar · GSW / John Wood · Paloma · HTP / Westinghouse / American Standard (water heaters) · Giant · EcoSmart / Eemax · Stiebel Eltron
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