While duct tape may have many uses, ironically, sealing heating and cooling ducts is not one of them.
As it turns out, the adhesives used on standard plastic duct tape dries out quickly and ceases to hold.
Solution: The real stuff, which is called aluminum foil tape. This is a 2-mil aluminum foil duct tape with a paper release liner. It goes on easily and stays on the duct for the duration — even the lifetime of the ductwork in most cases.
Sealing both the supply and return ducts are beneficial for a few reasons. Sealing the supply ducts (the ducts that the air is forced through and then up into your home) is a great idea to keep the air flowing where it was intended to and not through unsealed cracks and seams, which makes some areas hotter or cooler than they should be. A good example of the latter is how cold it tends to be in your basement when you’re running your central air conditioning.
In many cases, ductwork is exposed openly in a crawl space of a home. We definitely don’t want to lose any heating or cooling there. That’s just money down the drain.
For return air ducting, it’s important for the furnace or air conditioning blower to “draw in” just as much air as it pushes out. This is what return air does. It draws the air in to give the blower something to blow. Leaking return ductwork can mean it’s drawing air in from places you may not want it to, such as crawl spaces, musty basements, laundry rooms or even bathrooms!
The vast majority of houses’ ducting systems lose as much as 23 percent of air into unwanted spaces. This can be a big waste of money and even harmful to your health.
Joel Wensley is licensed mechanical contractor in the state of Michigan, a member of the Comfort Institute and is also the president of Mechanical Heating & Cooling in Dearborn Heights