How to tell the age of furnace and heater?

I have encountered several cases of embrassment when customers asked about the age of furnace and heater. I could not find any hint on the equipment. Could anyone tell me any technique how to evaluate the age of these equipments? Thanks.

Age Is found in the serial number based on manufacturer
If you email me I can send you a list that I have later

Thank you for reminding me. I have got the similar file now.

Why are you embarrassed Yi?

Just tell them it’s hidden in the model number and you’ll go look it up.

I do this all time.
I could care less how old the equipment is in most cases and when I’m asked, I’m not prepared with the answer.

I have the picture of the nameplate and I tell the client I will give them the “date of manufacture” (which is not the age of the equipment installation) if they require it.

Nobody seems to bat an eye with that response.

You don’t need to know know everything.

You just need to know where to get the information.

[size=2]Quoting equipment age off the cuff can create some sticky situations if you happen to analyze the equipment model number incorrectly (as many manufacturers do it a different way).
I never provide equipment age unless it’s pertinent to an adverse circumstance.
Theoretically, if you report the equipment is being two years younger than it actually is (by misinterpreting the month of manufacture with the year of manufacture, you may have a client coming back when the equipment fails and requires replacement wanting to know are the other two years of “life expectancy” is and expect you to compensate them for it.
All this potential headache for just trying to be the home inspector whiz kid attempting to predict life expectancy of a mechanical device (which is specifically addressed as being outside the standards of practice).