Diligent care keeps your furnace doing what it’s supposed to do best: warming your building and keeping you toasty during chilly weather. However, several problems can prevent your furnace from operating as it should, and the more you learn about them, the better prepared you will be to identify them and find solutions should they ever occur. One of the most common troubles that plague furnace owners throughout the United States and beyond is that of a furnace that leaks air from the ducts. Leaking ducts can stop your furnace from warming the air in your home adequately—although they will not prevent it from running and wasting energy. As a result, leaks can cost you a lot of money over time and still leave you shivering. One questions our clients often ask us is whether they should use mastic or furnace tape to fix leaks. The answer may surprise you.
What Are Mastic and Furnace Tape?
Firstly, let’s take a more in-depth look at what mastic and furnace tape are so that we can compare them. Those of you who do not yet possess detailed HVAC knowledge might never have heard of either of these tools before, so it’s important to start with the basics. Here they are:
- Mastic is a form of construction adhesive used in a wide variety of home improvement tasks. It is typically found holding tiles together in floors, walls, and ceilings. Mastic may also be used to join panels made of plywood, concrete, or even leather and certain textiles. There is a specific form of mastic known as duct mastic that is commonly used to seal ducts in HVAC systems.
- Furnace tape is a term referring to several different varieties of foil and metal tapes coated with adhesive on one side. This tape is almost exclusively used for sealing ducts. Depending on the quality of the tape, it can last for long periods of time.
You can use each of these tools in certain cases, but choosing between them depends on specific circumstances. In the following paragraphs, we will examine several considerations that can (and should) affect your choice.
Wait a Second—What about Duct Tape?
Hang on, did we hear you right? You want to use duct tape to fix leaks in your ductwork? Wait for a second—it sounds reasonable when you put it like that. Too bad “duct tape” is a misnomer. It turns out that duct tape is actually the last thing you should use to try sealing your ducts. It isn’t even approved for use on them. Whoever came up with the name for it probably just had a cruel sense of humor.
Don’t get us wrong: duct tape can be exceptionally useful in a wide variety of tough home improvement projects. However, it isn’t designed to withstand the heat and dust that tend to be present in an HVAC system for long periods of time. In fact, duct tape will probably only solve your problem for a couple of days, tops. Of course, that’s utterly hypothetical since you should never use an unapproved project on your ducts in the first place. If you did, the duct tape would probably melt and could even become a safety hazard—just trust us and don’t try it.
So—Mastic or Furnace Tape?
Let’s return to the matter at hand—the big showdown; the battle royale. Two home improvement products enter, and one home improvement product leaves! Just kidding. This isn’t life or death. Both mastic and furnace tape are specifically designed to seal leaks in HVAC ducts. You can use either one without courting disaster. However, just as we said before: either product may serve you better in specific scenarios. Here’s how to know which one you should choose for the leaks in your ducts:
- How much do you care about appearances? Mastic is reliable, but it can also look a little bit sloppy to have gobs of paste holding your ducts together. Tape, on the other hand, can provide a clean aesthetic and give your ducts some class—assuming you’re worried about visitors judging your ducts.
- How much can you afford to spend? Here’s the thing about furnace tape: it’s cheaper than mastic, but only on the low end. High quality furnace tape tends to be more expensive than mastic. That said, most licensed contractors advise against using low-quality furnace tape because it rarely lasts longer than a few years. If you want to avoid replacing it on a semi-regular basis, either go with mastic or invest in some primo furnace tape that will stand the test of time.
- What materials are you most comfortable handling? You might not be the kind of person who likes to get their hands dirty—in which case, mastic is probably not for you. Then again, if you’re into arts and crafts, you can consider it a creative project. It’s really up to you.
Mastic and furnace tape each have unique properties that can make them better for some HVAC owners than for others. Review the above information before you hit up the hardware store, and you should be able to select the tool that best fits your style and budget.