3 Types of Duct Insulation for Attics

Are your energy bills out of control? Does it seem like your HVAC unit is working overtime, but your house still isn’t reaching the desired temperature? 

It sounds like you might need to insulate your air ducts. 

Learning how to seal ductwork properly is the key to a more energy-efficient and comfortable home. But with a few different types of duct insulation, choosing the one that’s right for you can be overwhelming.  

Read on for a breakdown of the three different types of duct insulation. 

Duct Insulation Types

There are three types of insulation commonly used on air ducts. While some of these insulations can be applied inside the actual ducts, that’s really only practical if you’re putting in a whole new HVAC system. More often, you will use these insulation types on the outside of your existing ductwork insulation. 

The three types of duct insulation are: 

  • Duct board – This flat and study material comes in various R-values. Because of its inflexibility, duct board is typically only used with rigid ductwork. While this might be viable in modern homes or rooms outside the attic, the duct board’s size and shape may pose some difficulty for tight spaces like the attic. 
  • Duct liner – This material is used inside ducts and may not be practical unless you pull apart your HVAC system. 
  • Duct wrap The most common form of duct insulation type, duct wrap is measured and wrapped around ductwork to insulate. Duct wrap comes in various materials, from simple bubble wrap to fiberglass. 

Types of Insulation Materials

There are three common materials that most types of duct insulation are made from. Deciding which material is right for your ductwork insulation depends on your home, your budget, the space you’re insulating, and the kind of ducts you have. 

The three most common air duct insulation materials break down like this: 

  • Fiberglass – The most common insulation material. If you ask someone to visualize insulation, they probably imagine pink and puffy rolls of fiberglass insulation. Flexible rolls of fiberglass are especially well-suited for attics, where their pliable shapes can be easily contorted around complex ductwork. 
  • Polyethylene Compared to fiberglass, polyethylene insulation is more expensive. That said, polyethylene is suited to outdoor ductwork as it’s made to withstand the elements.
  • Rockwool – Another more expensive choice than fiberglass, rockwool offers soundproofing features. If you’re insulating the inside of your ductwork, rockwool tends to be a good choice because its durability makes it less likely to tear. For the environmentally conscious, rockwool is made from recycled materials, which make it a green alternative.

The most commonly used combination of insulation type and material is fiberglass duct wrap for insulating the air ducts in an attic. 

What is R-Value?

If you’re shopping for insulation, you’ve likely encountered the term “R-value.” That indicates how much thermal resistance each kind of insulation has. The higher the insulation R-value, the more resistant it is to heat flow. 

Different parts of the country require insulations with different R-values. For example, when insulating ductwork in an attic in California, you’ll want to get insulation with a minimum 30 R-value. 

Reasons to Insulate Ductwork

Before getting into the different types of insulation, it’s important to understand how to insulate ductwork in attic and the benefits of properly insulated air ducts. 

The conditioned air that passes from your HVAC system through your ductwork can often run into problems, particularly in the attic, which isn’t typically air-conditioned or heated. This means the unconditioned air from the attic, along with its dust and odors, can seep into your uninsulated air ducts and change the temperature and quality of the air. 

With properly insulated air ducts, you’ll enjoy:

  • Better air quality throughout the house
  • A less fatigued HVAC system
  • A quieter environment that’s free of odors
  • Lower energy costs

Insulating air ducts is a project that eventually pays for itself.1 The question isn’t so much whether or not you should insulate (you should), but what insulation you should use. 

Insulate Your Ductwork with Attic Construction

There are numerous benefits to insulating the ductwork in your attic. But, even once you’ve learned about the different duct insulation types, you might still feel overwhelmed taking on such a project yourself. 

The friendly professionals at Attic Construction are here to help. 

We have decades of experience with air duct cleaning in San Diego, Phoenix, and the Orange County area. We’ve seen every kind of ductwork out there and haven’t yet encountered an attic so cramped or cluttered that we couldn’t work out a way to improve the home’s energy efficiency. 

Don’t waste energy—let the folks at Attic Construction help figure out which duct insulation is right for you. 



  1. Forbes. How Much Does Duct Insulation Cost? https://www.forbes.com/advisor/home-improvement/duct-insulation-cost/


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