How To Look At A House
McGarry and Madsen's home inspection blog for buyers of
site-built, mobile/manufactured and modular homes
How can I determine the age of a GE (General Electric) gas furnace or air conditioner from the serial number?
Thursday, June 14, 2018
Very, Very Old
If the unit has a GE nameplate, you don’t have to decode the serial number to get an answer: very, very old, at least 30+ years. General Electric sold their division that manufactured central heating and air conditioning equipment to Trane and ceased production in the 1980s. We have not come across a GE condenser in the last five years, but occasionally see a corroded gas or electric furnace still in chugging along—like this one we inspected yesterday.
General Electric used several different letter and number formats over the years, but the all-numerical versions had one thing in common. A single number indicated the last digit of the year of manufacture, which forces you to guess the decade by looking at the condition of the equipment.
The serial number format for the furnace data plate shown above uses the last three digits of the serial number for the year and week of manufacture, with the third from last being the year and final two numbers are the week. So “740” means this unit was produced in the 40th week of 1967, 1977, or 1987. We suspect it was 1977 because the home was built in 1978 and the furnace appears to be original equipment; but, either way, our all-purpose answer of “very, very old if it’s GE” still holds true.
For the age of another brand or manufacturer, go to our blog post How do I determine the age of my air conditioner?
To determine other key specs of your HVAC system, see one of these other blog posts:
To find the age of other home components, go to How can I find out the age of a roof? and How do I determine the age of an electrical panel? and How do I determine the age of my water heater? For life expectancies, visit What is the average life expectancy of the components of a house?
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To learn more about heating and air conditioning systems, see these other blog posts:
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Field Guide for Home Inspectors, a quick reference for finding the age of 154 brands of HVAC systems, water heaters, and electrical panels, plus 210 code standards for site-built and manufactured homes, and the life expectancy rating of 195 home components. Available at amazon.com for $19.95.
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