Should Ductwork Be Insulated?

Ductwork plays a significant role in every HVAC system. However, there is a question that we should answer. Should ductwork be insulated? So, to feed both our curiosities, we have conducted thorough research on that matter.

Yes, it is highly recommended to insulate ductwork. There are three essential benefits that it can provide you, and these are:

  1. Insulating your ductwork can reduce your energy consumption
  2. It can lower your monthly electricity bills
  3. It can give you a more comfortable home

These three benefits might be simple, but the more you know about them, you'll see why insulating duct work can have a substantial positive impact. We suggest you keep reading to learn more about ductwork and insulation.

View of fiber glass duct for central air in an attic - Should Ductwork Be Insulated

The Importance Of Insulating Your Ductwork

Installation system HVAC duct ventilation pipes in silver insulation of central conditioning a wall

Insulating ductwork ensures that the air circulating through the duct system will not leak and keeps the temperature as it should be. If there is leaking or the air escapes from the duct system, expect that it will promote energy loss.

Energy loss will lead your HVAC system to work harder than it should be. The consequence of wasting energy will produce a higher electricity bill, which is not suitable for both the environment and your pockets.

Improper ductwork insulation will lead you to lose 10% up to 30% of the energy utilized to cool or heat your home. Alternatively, proper ductwork insulation will not only prevent your energy consumption go to waste but will also prevent leakage, condensation buildup, and, most importantly, temperature drops.

Ductwork Insulation Stops Condensation

Condensation in the ductwork can occur when cool air passes through warm regions of your home. And this causes moisture to build up inside the duct system's enclosed area. As a result, moisture can cause various issues, including mildew and mold growth. In addition, proper ductwork insulation can stop condensation from happening.

What R-value Is Best?

Most HVAC professionals suggest that insulation on ductwork should have an R-value of at least five. However, the highest R-value, which is seven, is ideal.

Where Is Ductwork Insulation Most Needed?

Because ducts are commonly composed of thin materials, such as fiberglass or sheet metal, air passing through them is easily lost. Ductwork insulation is essential in unconditioned areas such as floors, basements, and ceilings.

Seal Ducts Before Insulating

Before you start adding insulation to your ductwork, it would be best to seal all the leaks in the ductwork first. You can do it yourself as long as you have enough knowledge, or you can ask for the help of an HVAC professional to seal them and check some potential damage on your ductwork.

With the help of a mastic, you can seal all the leaking areas. Then you will have to brush on the locations and leave them for 24 hours to thoroughly dry. It is a highly reliable material for sealing because it won't disintegrate or shrink away from the joints.

Additionally, it would be best not to use duct tape when sealing ductwork. It could decay and disintegrate, losing its ability to seal the leaks properly and leaving you with a worthless, sticky mess on your ductwork.

Types Of Ductwork Insulation

Fiberglass is the most prevalent ductwork insulation material. Duct wrap, such as Reflectix, is a newer and more effective solution. And below is how the two materials compare:

1. Fiberglass Insulation

View of fiber glass duct for central air in an attic.

  • low cost
  • it can absorb noise
  • easy to replace
  • the installation process is easy
  • you should check moisture absorption regularly

2. Refelectix or Duct Wrap

  • this material is highly efficient and stable
  • lightweight material
  • on the outside, there are foil faces that retain the bubble pack between layers of polyethylene
  • according to the specification of the manufacturers, Reflectix has an R-value of 5.6
  • as opposed to fiberglass, there is no chance of moisture concerns

Ductwork Insulation In Different Locations

How To Insulate Ductwork In An Attic

house attic insulation - construction worker installing rock wool in mansard wall

At best, you should not install ducts in a vented, unconditioned attic. However, if you have already done it, you should move the ducts inside your home's thermal envelope.

If you have vents in the ceiling, your property has ducts in the attic. And if you intend to leave the ductwork in place, you will need to insulate the system. It can be challenging to install insulation in unconditioned spaces since you must avoid sweating. Condensation can form on the ductwork due to the temperature variations, which you must avoid.

The first order of business is to locate and repair any leaks. Once you finish, you can start insulating with one of the methods we mentioned above, or you can try the blown-in cellulose insulation:

  • you have to make sure that the location of the ducts are on top of the rafters
  • try to cover the ducts with cellulose completely
  • if you notice that there are still uncovered areas left, you can opt to utilize insulating blanket material
  • it would be best to use a quality bowing machine and hose

Read more about: "What R Rating To Use For Attic Insulation?"

Insulation Around Ductwork In The Ceiling

The presence of ducts in the ceiling has several drawbacks. When the heat rises and begins in the ceiling, expect it has nowhere to go but up. So, as a result, your furnace usage is inefficient.

However, if you have ducts in the ceiling and know that the entire area has sufficient insulation, you may no longer need to insulate the existing ductwork.

Is It Necessary To Insulate Basement Ductwork?

The most important thing to remember is that insulating the ductwork in the basement will cause the space to be significantly colder. If you reside in a location where the winter season is extremely cold and you have a lot of water pipes and drains running through your basement, anticipate that the pipes and drains might freeze and break during such a season.

However, you can do something to avoid that. And that is to utilize an electric heating tape wrap that you should apply to the water pipes. Or, if you want, you can also consider insulating both the ducts and the basement walls. 

Read more: "What To Set Dehumidifier At In Basement? [Summer And Winter]"

Insulating Ductwork In Crawl Space

New air conditioner vents in new home construction

Crawl spaces are just like the attics. It is an unconditioned area with extreme temperature swings. So, it would be best to install furnace ductwork insulation. That is to help you save money and energy consecutively.

It will additionally include saving money from costly furnace repairs and maintenance. And just like the other insulation methods, it would be best to insulate your crawl space ductwork properly to avoid condensation.

However, we highly recommend having an HVAC professional insulate your crawl space because working in such a small space is exceptionally demanding.

Ductwork Insulation Cost

You can determine the ductwork insulation costs in several aspects. And they are typically between $0.90 and $2 per square foot installed. Now, let us take a deeper look at what you are getting for your money:

1. The Measurement Of The Ductwork

The more ducting there is, the more costly the insulation will be. You can determine the price by the insulation ratings. For instance, R-3.5 costs cheaper than R-8.0.

2. The Thickness Of The Ductwork

If the ductwork is thin, you will need to add more insulation material to achieve the appropriate thickness. Professionals highly recommend it so that it can meet the required insulation levels.

3. Additional Materials

Unfortunately, you won't be able to directly adhere the medium to the duct because you will need various other supplies. For every 1,000 square feet of insulation, expect to pay $20 to $50 in supplies.

4. Labor Costs

You can try to do the job yourself as long as you know how to do it and if the job is a small project. Alternatively, hiring a professional will be the time if it is an immense task. And the service will require labor that costs $0.80 per sq. Ft.

While the installation process is costly, high-quality ductwork insulation will help you save on your monthly electricity bills.

Wrap It All Up

A worker is sealing two sections of house attic vent duct insulation with aluminum foil tape.

This article showed you how vital ductwork insulation is. And as a homeowner, the most significant benefit it can give you is saving money and improving comfort.

We hope you find this article helpful. And if you want to read further, you are free to browse our website and check some articles that might be of your interest. Or you can check these out!

How Much Does It Cost To Install Central Air With No Existing Ductwork?

What’s The Best Kind Of Insulation For Interior Walls?


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