Your air ducts are like the blood vessels of your house – carrying life-saving resources (warm or cool air) from one area to another.

If something goes wrong, they’re going to have to see a doctor and today, that doctor is you!

Ducts are usually made with aluminum or galvanized steel, which are less than ideal when they’re used on their own. For hot air, it gets heated in the furnace and is then pushed by fans to various rooms of your house. But since the ducts are so thin, that air cools down before it reaches its destination. 

The same can apply to air conditioning.

By the time that it reaches your room, you lose some of that coolness through the duct walls. If less hot or cold air is getting to the rooms, then you will need more of it to heat or cool them. This could cause a whole host of problems, such as raising your electric bill.

But fret not! This is where insulation comes into play. When you wrap a layer of insulation around your duct, it’ll reduce the loss of hot or cool air. The thicker it is, the harder it’d be for the air to escape. 

This guide will walk you through the process of insulating your ducts. It’s a lot easier than it seems, so let’s get right to it!

Steps For Insulating Your Ducts

Before you start, make sure that you have proper protective gear.

Wear a pair of safety goggles, gloves, long-sleeved clothing, and a dust mask. You’ll want to avoid inhaling fiberglass particles or getting them in your eyes and on your skin. 

If you start to feel uncomfortable at any point, stop and call a professional.

Saving some money by doing things on your own is great, but your health is also important. Please ensure that you take the right safety precautions as fiberglass is no laughing matter. 

If you’re ready to go and you feel confident, let’s get started!

  1. Check for any leaks. Before you start insulating your ducts, you should check if there are any holes to seal. Turn on your HVAC system and feel for any air – that’s how you’ll find the big leaks. For smaller leaks, use a stick of incense or smoke pencil.
  2. Cover those leaks. If you do find holes, use foiled duct wrap. It’s metallic foil tape that’s specifically made for sealing ductwork. It’ll prevent condensation and mold from gathering on the duct. For this reason, please don’t use regular duct tape. It also won’t handle extreme temperatures very well.
  3. Choose your fighter – your insulation. When you pick out your fiberglass, check for its R-value. The higher the R-value, the better the insulation, so find fiberglass insulation that’s at least R-6. You can choose to get foil-faced insulation, but you can also use foil tape to cover everything up.
  4. Cut insulation to size. Measure the width and length of your duct then add two inches. You’d want the insulation to be nice and snug up, but too tightly. Use a sharp utility knife to cut through.
  5. Wrap and tape it up. From the bottom, slide the insulation around the duct and make sure that the ends meet at the top. Put small strips of foil tape that go along the stream so it’ll hold in place. Afterwards, tape the entire length of the stem.
  6. Keep on wrapping and taping! Repeat steps four and five until your duct is completely covered. Make sure that you don’t leave any gaps and don’t stop until all you see is foil. This will prevent moisture from soaking through the insulation and condensing on the duct.
  7. Optional: Secure with wire. If you really want to be an overachiever, get some simple wire and wrap it around your duct. Wrap two pieces of wire for every four feet.
  8. Congratulations! You’re finished! Now pat yourself on the back and enjoy your hot or cold air. 

Does the Basement Ductwork Need to Be Insulated?

In short: yes!

In long: yes, but here are the reasons.

Let’s use an example.

When you make yourself a cup of coffee in the morning, do you put it in a thin, metal bottle or a thick thermos? The difference between the two beverage storage devices is the insulation. As the walls of your bottle and thermos get thinner, the temperature of the environment around it has a greater impact on the liquid inside. 

The same applies to your ducts. When you leave your ducts in their natural and uninsulated state, you’re allowing the air temperature around them (i.e. in the walls/basement/attic) to affect the air temperature inside the ducts (i.e. the air that we spend our hard-earned money on).

As you may have guessed, the cold air surrounding the ducts will cool the warm air within the ducts down to a less than optimal – as set by you – temperature. The same applies to hot air around the ducts, affecting your air conditioning. 

If that wasn’t enough of a reason to insulate your ducts, uninsulated ducts leave you at the mercy of mold and mildew! 

When hot and cold air interact, condensation will occur and you’ll have water.

With hot air inside the ducts and cold air on the outside, you’ll have a shiny coat of condensation. This type of condensation tends to accumulate in the tight, enclosed crawl spaces that ducts normally crawl through.

As such, low air circulation and condensation will more than often lead to mold and mildew.

Is Insulating Ductwork Worth It?

By now, you should at least be considering the potential risks of uninsulated ductwork.

But is it even worth it to fix?

How much does the temperature drop?

When, if at all, will I deal with mold and mildew? 

If you plan on being in your house for the foreseeable future, it is absolutely worth it to insulate your ducts. Did you know that you typically lose 20 to 30 percent of heating or cooling energy?

Up to nearly a third of your money is going to waste! 

Not to mention the state of your furnace and air condition. Insulated ducts can save them from working as frequently or as hard, which may increase their longevity. This is what I call a win-win situation.

As for mold and mildew, you may never have to deal with this problem if your ductwork was correctly installed with the necessary precautions. But if you do have a mold problem, it’s more often than not that you won’t realize until it becomes a gigantic headache for you and hole in your wallet.

How Much Does It Cost to Insulate HVAC Ductwork?

Unfortunately, there isn’t a single answer. There are a lot of circumstances that can change the cost. However, we will walk through the process and give you an example to use as a general price range. Let’s get started!

The Expense Factors

There will be a number of factors that will determine the cost to insulate your ductwork. But worry not. We can help you make sense of these factors before you run to your hardware store or get on the phone with your contractor.

The Price of Insulation

You may have chosen to either tape up your insulation or save the trouble by buying foil-facing insulation. The latter option obviously costs more, but it may also save you precious time and energy.

The R-value of Insulation

We briefly mentioned this in the instructions, but in layman’s terms, this is the thickness degree of the insulation.

The type of insulation that you use and how much you use it can also influence the value.

Generally, it is recommended that you add one to three inches of insulation in R-values of six or higher. However, the more extreme a climate you live in, the higher you will want your R-value to be – and higher the cost.

Professional Costs

If you decided to skip the guide and called a contractor, you’ll also have labor costs. Depending on the material you choose to insulate your ducts with and the complexity or fragility of your ducts, the cost of labour can vary.

Afterward, you’ll be quick to insulate your ducts when your inevitably reinstall them.

Example Prices

Using this handy calculator, you can see generally how much materials, labor, and tools will cost in each state and for what size of an area. But here is an outline of how much you’ll generally be looking to spend.

For our example, we will be using Florida and rounding up to the nearest five or ten dollars. We will also be using 1,000 square feet as the size for the insulated area.

If we use contractor-grade materials, you’ll be looking at a price range between $380 to $470.

For supplies and tools for preparation, job completion, and site cleanup, it’ll range from $40 to $45.

For labor, you’ll be paying for about 12 hours of work and anywhere from $385 to $985.

The Final Verdict

Based on the example above, here are your prices.

If you choose to do the job by yourself, you’ll most likely spend $420 to $515. 

If you choose to do it with a contractor – who will provide their own materials and tools – you’ll be paying from $805 to $1,500. 

By insulating your ducts on your own, you can save from $385 to $515 without a professional! Phew, that’s no pocket change!


Are you looking to save up to 30% on energy consumption? Do you want to lower your electric bill? Does your spine crinkle at the thought of breathing in mold or mildew? Do you want to eliminate one of the factors that can contribute to mold and mildew’s growth?

If you said yes to any of these questions, then insulating your ducts is the way to go. 

You can choose whichever approach you like best; Whether you are feeling up for a challenge and want to try your hand at HVAC repair or want the peace of mind and ease of hiring a trained professional.  Regardless of which option you choose, make sure to do your research and shop around for the best rates of materials and, if applicable, labor.

If you’ve made it this far into the article, I would like to thank you for taking the time to read it.

I hope that you have come out of this by being a little more knowledgeable on the importance of insulating your ductwork and how to potentially go about it. 

Consider reading another of our informative articles or sign up for our mailing list. You never know what else in your house might need an upgrade!

-Hyo Heather Park 

About The Author

Heather has always been the type to tinker with whatever she could get her hands on. As a child, it started with toys, but as an adult, it grew into appliances.

She believes that you shouldn’t have to crawl through a million websites to find an answer to your problem. By writing short but highly informative articles, she provides readers with the immediate solutions that they need. She also likes to keep it casual so readers don’t get bored or feel like they’re reading a textbook.