Preston's Guide, What's the deal?

I get that they stopped making Preston’s Guide but I can’t find a copy anywhere! Can anyone give me some help on this. I’m looking for an up to date reference guide for determining the age a furnace, heat pump, a/c etc.


Try this link…


Save this link. Invaluable.

Here are the ones I use. When I am stumped I go to the internet.


Johns building center website is invaluable, he is the Executive Director of our association:

National Association of Commercial Building Inspector & Thermographers™

We will be at the Casey & O’Malley Conference in Atlantic City April 22-26th.

If anyone wants to meet John Bowman in person, come to the conference, we have many items we’re giving away, such as date code charts for all air conditioning and water heater equipment, and many other goodies.

There will be great educational sessions available for just about everything, including commercial building inspection information and also a commercial management course April 56-26th.

Great!! Thanks for the help guys.

If you still want Prestons Guide, It is here It looks like the last update was in 2005. I myself use as well and have been slowly making it into an offline pdf version for quick in the field lookups. It took a little time, is up to date and didn’t cost $125.

I apologize for any confusion. The Preston’s Guide has not been discontinued. Perhaps because we no longer have a toll-free number it was assumed we were no longer taking orders. We have streamlined our ordering process and customers can now place orders by going to our website Orders are filled and shipped within 24 - 48 hours.

George Monagle
The Prestons Guide

There ya have it, straight from the horse’s mouth. Thanks George!

Thanks George. Are there plans for an updated version in the near future?