Why not Thermal Labels in HVAC?

A number of people have asked us recently about thermal labels. We do make them, but for other industries. In order to understand why thermal labels aren’t a good fit for the HVAC industry, you have to understand the technology involved.

*There are two types of thermal labels: direct thermal and thermal transfer. *

First, I’ll tackle the direct thermal label. Direct Thermal material has the ink built into the label. That way you don’t use any toner, ink, or ribbon. Sounds like a good start, doesn’t it? The printer activates the ink with heat (hence the thermal part of the name) and creates the image: information, duct, barcode, etc. For ductwork, the metal is being cut with a plasma torch. This heats the metal up. If you apply a direct thermal label to the heated duct, it will activate the dormant ink still in the label. The result can be a very dark label (it won’t be uniform though).

The next problem is dragging ductwork. Although many shops don’t like to admit it, the duct tends to get dragged from one station to the next. Dragging it creates pressure. If there are any pebbles, dirt, etc., on the ground it will come into contact with the label. Pressure = heat. Your label will now have streaks across it where the pressure was applied. Although this isn’t a huge deal, it rears its ugly head when you are using bar codes. Now on your bar code you’ve got some random lines that are interfering with it.

Another issue is storage. Many shops store their duct outside. Direct sunlight and general summer temperatures can and will cause problems with the thermal label. Depending on conditions, the label can quickly become blank. Imagine having a yard full of duct for a job and when you need to load it to the jobsite, all of your labels are blank or extremely faded. I can hear the cursing from here!

Think of a receipt. That material is the same idea as thermal labels, just without the adhesive. Stick it in your wallet and what happens? It gets dark and fades. Here’s an experiment: get a receipt and leave it in the sun. That is what will happen to your ductwork’s labels. Direct thermal technology works in some industries, we make tons of them. It just isn’t a good fit for HVAC work.

Thermal transfer labels use a ribbon instead of embedding the ink in the paper. It is like an old typewriter that had a ribbon. It is the same concept, except typewriters reinked the ribbon as it rewound itself. Thermal transfer ribbons don’t do that. They are a one for one transfer. If you go through 1000 labels that are 6 inches, you will also go through 500 feet of ribbon – regardless of how much you print on the label. (1000 6” labels = 500 feet.) Our current price on the ribbon is $15 for 1500’. For every roll, you are using $5.00 in ribbon. The plus side is that you don’t have the fading and darkness issues that the direct thermal has. On the flip side, you have much higher cost AND have to have someone monitor the ribbon situation in the printer. For some applications, it works. In HVAC it is a competitive disadvantage.

Now that we’ve discussed the nuts and bolts of the actual label, let’s look at the printer. A thermal printer can be expensive. They can also be cheap. That isn’t really the issue. Mainly, the printer is slow. A run-of-the-mill laser printer will print anywhere from 15-25 pages per minute. With 6 labels per page that is 90 to 150 labels per minute. For example, I just printed off 10 labels from my UPS thermal printer (same size label) and it took 34.56 seconds. At that rate, printing 90 labels (low end laser printer speed) would take over 5 minutes. In addition, shops are already using laser printers for the reports. The thermal printer is just a specialized piece of equipment that has one job, that is subpar in a shop environment.

I hope this helped explain the differences and drawbacks of thermal technology in HVAC. If there are any other questions, feel free to shoot us an email at: sales@bannersalesco.com!