DIY: Sealing Ductwork from the Inside

A majority of the homeowners are unmindful of the importance of sealing the air ducts. However, it is one of the most critical things to keep your home energy efficient. First, you must understand that ducts are the primary source that dispenses conditioned air throughout the home. Unfortunately, these channels are likely to have gaps in their connections that allow air escape before reaching the target area. So, this article will be a guide for DIY: Sealing ductwork from inside.

A significant amount of energy is lost during the way when the air escapes through holes. Also, leaky ducts allow invasion of dust and dirt. Thus, it affects indoor air quality and badly impacts people’s health.

Hence, to prevent this, duct sealing is crucial. You can do it in a traditional way or by hiring Air duct cleaning in Marietta, GASo, adequately sealed ducts help you balance indoor air temperature and enhance air quality. 

Ductwork Closing: Is it a DIY Project?

Usually, homeowners ask whether sealing ductwork from the inside can be performed through DIY methods, or should they hire a professional? So, the answer is both ways have their pros and cons.

So, if you are confident that you can fasten your ductworks without a professional’s help, you can give it a try. However, if you feel it is not your cup of tea, you must consider hiring Dryer vent cleaning in Marietta, GA.

So, before starting with this home improvement task, you must have the proper knowledge of the best and safe ways to perform it.   

How to Cap Ducts Yourself?

So, if you have decided to carry on a DIY duct sealing project, you should first test your ducts for any leakage. You may use a lit incense stick or slender piece of toilet paper at each duct connection. Keep it at the stagnant position, while the air is turned on. And if the article starts moving unpredictably, it indicates an air leakage.

So, when sealing the ducts, experts recommend the use of mastic sealants. Unluckily, duct tape is not a good choice as it starts to peel off quickly. So, if mastic sealant is not available, you should look for HVAC aluminum foil tape.

How to Cap Ductwork in a Traditional Way?

  • You may use a continual stripe of foil tape to cover the longitudinal layers along with the straight runs of the ductwork.
  • After this, you may use a paintbrush for mastic sealant application to join the elbow to a duct.
  • Before applying the insulation, you must measure the duct circumference and use a knife to dissect the foil fiberglass insulation in the correct size. You may keep the size a bit flexible as it will help in drawing the ends together.
  • Cloak the lining around the duct and squeeze the seam locked.
  • You can secure the insulation with tiny foil tape strips and then apply an extended foil tape along the layer.
  • You may repeat it (until the entire ductwork is insulated).
  • To fix preformed duct insulation, you should begin by detaching the elbow to uncover the duct ends.
  • Snap a plastic covering on the ends of the vents to secure the insulation from ripping, then glide the pre-formed part over the duct.
  • Gradually pull the lining over the entire length of the ductwork.

How to Seal Ductwork from the Inside?

If you want to cap the ductwork from the inside, it is a much more complex procedure. Hence, it is always a sensible idea to hire a professional. The HVAC contractors will film the inner side of the ductwork using a liquid rubber sealant.

The expert will remove the grills from the supply and return registers and lump them using foam rubber and wide tape strips. Then the contractor will use a blower fan to force pressure into the duct system. A computer program determines the amount of leakage.

A blower fan allows interior misting of your duct system with a specialized liquid-rubber sealant. It helps seal all the leakages, holes, cracks, and fissures. Then, the professional might continue with another pressurized blower test to analyze the outcome.

It is a fact that you have high energy bills during peak summer and winter months, mainly due to excessive HVAC use. However, if you observe an unusual rise in your bills or your HVAC system is working inefficiently, you must check your air ducts for any leakage.

Your HVAC unit tends to lose some air, even if your ducts are perfectly sealed or insulated. The reason is the notoriously inefficient ducts. Hence, if it is positioned in unconditioned regions of your home (like lofts and crawl spaces), the probability of ductwork inefficiency increases.

What are the Benefits of a Properly Taped Duct System?

High Comfort

Have you ever experienced the inconvenience of not achieving the desired room temperature, even if your HVAC unit works for hours? Also, do you have hot and cold spots in your home? What is the point of compromising your comfort if you are paying energy bills? So, your air ducts are likely to be the culprit. So, if you can figure out the leakages in the ductwork, you may try DIY sealing. Otherwise, hiring a professional is the best idea.

Energy Efficiency

By now, you must know that poor connections and leaking ducts can significantly disrupt the efficiency of your HVAC system. So, if you want your energy bills to remain steady, proper ductwork insulation is the ideal solution.


A properly capped ductwork system is evidence of a safe HVAC system. So, if you want peace of mind, protect your HVAC units through timely maintenance, ductwork insulation, and sealing. For this, you must regularly check your air vents blockage (by furniture or another item).

Which is Better: DIY or Professional Service?

Experts recommend hiring a professional for the majority of the HVAC tasks. However, if you feel that your system needs more than simply capping a ductwork leakage, you must immediately hire a reliable contractor. Hence, it will shield you from costly repairs and more significant losses.

Also Read: Benefits of Humidifier for Your Health and Home


Leave a Reply