Our most popular sections on this site are serial number age decoders for Water Heater brand listings, and for HVAC related equipment (Furnaces, Boilers, Air Conditioners, & Heat Pumps). Each directory lists brand names alphabetically. To find a specific brand, please do the following:
- Go to the appropriate HVAC directory or Water Heater directory depending on the appliance type.
- Select (click) the letter the brand in question begins with.
- A drop-down list of available brand names beginning with that letter will appear.
- Select (click) the specific brand name in question.
- The selection will take you to that specific page where one or more examples of serial number styles will be listed on information slide images.
This site provides examples of manufacturer serial number styles. These are ONLY examples! YOUR actual serial number will differ from the provided examples! Your actual serial number can be compared to similar styles represented on our site to help you determine the date of manufacture. In other words, the included examples are intended to help you decipher the actual number off your HVAC or Water Heater data tag and will not be an identical match number for number, letter for letter. These examples are listed in slide images on the appropriate pages. Many brand pages will have MULTIPLE STYLES listed. Please be sure to scroll through ALL style examples provided to find one that most closely resembles your actual serial number.
FAQs & Helpful Tips:
Data tags/plates will be found in a VARIETY of locations on the unit and will vary by manufacturer. In other words, they can be located ANYWHERE and on ANY part of the unit. Most common locations include:
- - - on the outside of the unit cabinet, case or housing,
- - - below the brand name plate,
- - - inside service compartments,
- - - on the back side of a service access cover.
Occasionally, the model number and serial number are placed in different (separate) locations and will require a bit of looking or investigation to find both (older Lennox systems commonly did this with a separate small tag for the serial number). We cannot feasibly identify precisely where every data tag, serial number, or model number will be located on every unit for every brand. If you require assistance locating the data tag or its information provided, PLEASE CONSULT WITH A LOCAL CONTRACTOR or INSPECTOR.
Many manufacturers are now specifically including the date of manufacture stamp on newer units as part of the data plate information, or will explicitly indicate where in the serial number that the manufacture date is represented. Please be sure to look for these indications on the data tag when recording the model and serial numbers... It may save you a LOT of time!
If the data tag is missing, cannot be located, or portions of it are illegible, it typically becomes a "best guess" scenario. Sometimes the range of years a particular model was manufactured can be determined through the model number if it is available. This requires further research through industry specific publications such as Preston's Reference Guide, Carson-Dunlop Technical Reference Guide, Industry manuals we have accumulated which may no longer be in publication, and/or research through the particular company technical help/customer services or website (if available and if the company still exists).
If both the model and serial number are not legible or cannot be located, one may be able to determine approximate date of manufacture from internal components such as blower motors, circuit boards, gas valves, compressor, etc. Sometimes these may have a date stamp or tag indicating their date of manufacture which should closely match the overall date of manufacture... but may simply reflect the date that certain component was replaced. We have an additional tip resource page for these and other ways to estimate the age of a system HERE
Documents (if available) such as bills of sale, owners manuals, and service records may also help determine approximate year of manufacture or year of installation. The age of some very old systems often may only be determined through original company records such as bills of sale, purchase order numbers, etc. With luck, and if the company is still in business, one may be able to contact the company directly for assistance.
If all else fails, one may need to make a "best guess" based on the condition and appearance of the unit. Sometimes muted or drab colors of the unit such as light blues, greens, and browns can help determine an era of manufacture as these were common colors used during the 1950's into the late 70's and early 80's... but this is not a reliable method of determining age. Regardless, if the unit appears aged, neglected, or in disrepair, it likely is and may be a good candidate for upgrade to a more efficient unit design of current manufacture.
This information is often incorporated into the model number. While not always the case, typically the rule of thumb is to look for two consecutive numbers within the model number that are divisible by 6. Dividing this number by 12 will provide an approximate tonnage size of the air conditioner or heat pump.
For example... A Ruud air conditioner model number of UAMB-024JAZ indicates this unit is a 2 ton capacity.
In this example (UAMB -024JAZ), 24 is the first number divisible by 6. Dividing 24 by 12 equals 2 or 2 tons.
Similarly, a model number of UAMB-036JAZ indicates the capacity is 3 tons (36 divided by 12).
A sample model number of UAMB-030JAZ would indicate the capacity is 2.5 tons (30 divided by 12).
Sample model numbers of UAMB-048JAZ or UAMB-060JAZ would indicate 4 and 5 ton capacity respectively.
Again while common, this isn't always the case or the most accurate method. Additionally, some manufactures will include several more numbers in the actual model identification, proving difficult to determine which set of numbers actually indicates the size or capacity. Each manufacturer will have a unique and proprietary numbering system for model and serial identification. If you need assistance determining or confirming the capacity of your HVAC equipment or matching the capacity with the size of your home or commercial building, please consult with a LOCAL and experienced contractor, service provider, or the manufacturer directly! We will NOT assist you with this.
We have additional hints and tips for estimating the age of systems at our Hints & Tips page.
This website lists numerous HVAC manufacturers by brand with some known information, history, and available contact information. You can find this information listed alphabetically at our HVAC manufacturer info pages.
Ads stink and distract from the user experience. I despise them as much (if not more) than you, but they help us pay the bills here at Building-Center.org so they became a necessary evil.
Many of you have donated to our cause in the past and continue to donate! We greatly appreciate everyone's support both small and large, and it helps immensely! But it simply wasn't enough. The answer was to deploy Ads to help offset our personal costs in running and maintaining this site.
Numerous notable colleagues and inspectors have expressed over the years that we should turn the site into a "members only" access, and offered a variety of membership fee suggestions (typically far greater than the fees we currently ask). So... In an effort to improve the user experience without negatively impacting revenue from the ads, we have taken some of their advice and deployed ad-free membership options. We believe these to be very reasonable and inexpensive membership fees, and are continuing to add content and numerous exclusive benefits to the membership levels that will more than offset the meager fee.
You can read more about membership options HERE
Membership and Website Function FAQ's
First and foremost, THANK YOU for your voluntary donations and support of this site. It would be our pleasure to add you to the membership!
Please reach out to us from our contact page, and we will work on getting you registered!
The number 1 cause for this is your system or browser not configured correctly to retain cookies from the website.
Make sure your browser is set to retain cookies from the website. If your browser clears or flushes cookies after closing out, the “remember me” function will never work properly for you.
The persistent login should “remember” you for a period of up to 1 year; however, some periodic significant updates to the website software may render your system cookies as outdated and require you to login with each new session. We suggest flushing/clearing your browser cookies and then log back into the site to see if this corrects the problem for you.
Additionally, the site is currently set up to only allow 2 active logins at the same time from different devices or browsers. If you are logged in from more than 2 devices at the same time, the system automatically ends the oldest active login for the user while keeping the 2 newest logins active. This will require you to login again from the older session if/when you return to it.
If you would like to change your membership level, follow these simple instructions. These instructions apply if you are interested in upgrading or downgrading your membership level.
- -- Log in and navigate to your membership account page (link available at member landing page).
- -- From your Membership Account page under "My Memberships", click the link to “Change” next to your respective current level.
- -- The following screen will show you an overview of the available membership levels with links to upgrade or downgrade.
- -- After you select a new membership level, you will be directed to a checkout page in order to complete your membership subscription.
- -- Your previous subscription payment will be cancelled and a new subscription payment will be created. Important! - See subscription note below.
- -- After successful payment (if the level is paid), you will immediately have access to additional members-only content. If you are downgrading your membership, you will immediately lose access to previous members-only content.
NOTE - Important Subscription Fee Information:
Upgrades or downgrades in membership levels are not eligible for and will NOT receive reimbursement or refund of any previous subscription fees paid.
If you need to change/edit/update your billing (credit card) information, follow these simple instructions.
- -- Log in and navigate to your membership account page (link available at member landing page).
- -- From your Membership Account page, scroll to the bottom and click the link to “Edit Billing”.
- -- The following screen will show you an overview of your current membership level and respective subscription with area to submit new credit card information.
- -- After you have carefully typed in your new credit card info, select the "Update" button to complete.
- -- You should receive a message confirming your billing information has been updated.
A "Bad Gateway" error message is 99.9% of the time a client side (your browser or devices) issue.
The number 1 cause for this is your system, device, or browser not configured correctly to retain cookies from the website. Make sure your browser is set to retain cookies from the website for proper functionality during use.
The number 2 reason for this to happen is some periodic significant updates to the website software may render your system cookies as outdated (or perhaps appear "corrupted" to the server), thus preventing your browser from properly communicating with our servers. We suggest flushing/clearing your browser cookies and then access the site. This step typically resolves a bad Gateway error message.
If all else fails, try temporarily accessing the site from a different browser. If you can access from one browser but not another, this is a definite indication of client side (your browser) issue, and not a problem with the website.
The number 3 reason for a Bad Gateway error is incorrectly configured (or overly protective) antivirus software. We suggest "whitelisting" or reducing the protection settings for this site if you are using such software.