Installing roof insulation improves energy efficiency by reducing the heat flow to and from your home. But with advancements in HVAC systems, is the added cost still worth it?

The general consensus is yes! Roof insulation reduces electricity costs by 10-50%. It keeps your home cool in the summer and warm in the winter.

So, what type of roofing insulation should you buy, how much does it cost, and what should you consider? Let’s get into it!

What to Consider Before Installing Roof Insulation

Ventilation is a science. Several factors, such as the R-value, must be considered to optimize your home’s heating and cooling. This metric measures how effective an insulation material is at blocking heat flow.

Energy Star created a guide to help homeowners find the best roof insulation material based on location. Some areas are hotter or cooler than others, requiring higher or lower R-values.

Building codes require homes to have a minimum R-value, which depends on the state’s climate. Homeowners must consider this when replacing or installing a new roof.

Materials with higher R-values are better at insulation but will typically cost more money. So consider your budget when comparing the different types of roof insulation material.

Best Roof Insulation Material For Residential Homes

Material with higher R-values isn’t necessarily the “best” solution for your specific insulation needs. Finding the best material boils down to your budget, what you’re going for, and the roof materials you have installed. Here is a list of the best roof insulation materials to consider:

Spray Foam Insulation

Spray foam is the go-to material if you want quality insulation and aren’t worried about the price. It has an R-value of 3.6 to 3.9 per inch, making it thick enough to seal cracks and prevent moisture from entering your attic.

Although spray foam insulation is expensive, it can be an excellent long-term investment that improves the longevity of your roof, especially in areas prone to moisture build-up.

Average Cost: $2.75 to $6.50 per square foot.

Batt Insulation

Batt insulation is one of the most popular materials due to its variety and low cost. In some cases, double stacking compensates for the low R-values.

It’s also one of the easiest DIY materials to install. However, we advise you only do so with ample experience and the proper safety equipment, as it can easily irritate your skin, eyes, and lungs.

If you lack the right tools and experience, contact your local roof inspector to determine whether batt insulation is the best option for your home.

Average cost: $0.50 to $1.00 per square foot.

Loose-Fill or Blown-In Insulation

Loose-fill or blown-in insulation is made from fiberglass, cellulose, or recycled material like grounded newspapers mixed with borate. That means it can insulate, be a fire retardant, and also act as an insect repellent.

Contractors use a flexible tube to blow this into hard-to-reach areas of your roof, which allows you to control the overall R-value (3.2 to 4 per inch, depending on the material) that fits your climate.

Average cost:

  • Fiberglass: $0.40 to $1.10 per square foot.
  • Cellulose: $0.50 to $2.10 per square foot.
  • Rock-wool: $1.30 to $2.20 per square foot.

Rigid Foam Insulation Boards

Rigid foam insulation can serve as an air barrier, which helps seal the heat going into or out your home. There are three main types of rigid foam insulation boards:

  • Polyisocyanurate: Can serve as a radiant barrier with an R-value of 6.5
  • Extruded polystyrene: Water resistant with an R-value of 5
  • Expanded polystyrene: Least expensive with an R-value of 3.8

Average cost:

  • Polyiso: $0.65 to $0.85 per square foot.
  • Extruded: $0.60 to $1.50 per square foot.
  • Expanded: $0.40 to $0.75 per square foot.

Vacuum Insulated Panels

Despite their thin profile, vacuum Insulation Panels (VIPs) have one of the highest R-values among all roof insulation materials.

Some companies offer VIP technology with 16.8x the R-value of typical insulation materials. Even with just 2 inches of VIP material in your roof, this allows high insulation levels.

But this technology does come at a steep price. You’d often find VIPs at 10x the average roof insulation material cost.

Average cost: $10 to $12 per square foot.

Radiant Barriers

Radiant barriers don’t have R-values because they are not used for insulation. Instead, they block heat transfer. They’re best used on roofs with ample space between the decking and the roof.

That’s because radiant barriers deflect radiant energy. If your radiant barrier comes into close contact with your roof or other insulation materials, the heat transfer transforms from radiant to conduction, rendering it ineffective.

Underlayment and shingles can be installed right on top of some radiant barrier products, making it one of the easiest materials to install.

Average cost: $0.10 to $0.25 per square foot.

Structural Insulated Panels

Structural insulated panels (SIPs) are foam insulation panels lodged between two oriented strand boards (OSBs). Depending on the material, they have an R-value of 1.5 to 6.7.

They’re easier to install, provide structural support to your roof, and improve the overall air quality. However, improper installation can lead to water retention and leaks.

Average cost: $5 to $7 per square foot.

How Much Insulation Is Needed For My Roof?

There are many variables to consider if you want pinpoint accuracy when determining how much insulation your roof needs, which is better left to the professionals.

If you want to get a rough estimate, you can use Energy Star’s R-value map. For example, if you live in Texas, Energy Star recommends having R49 to R60 insulation in your attic.

If you plan on using closed-cell spray foam insulation with an R-value of 6.5 per inch, you’ll need about 9 inches of material to achieve the optimal R-value.

According to Architectural Digest, the average cost of closed-cell spray foam insulation ranges between $2.75 to $7.50 per square foot.

And that’s just the cost of materials. You also have to account for labor costs, which differ depending on where you’re located, the size of your roof, and the complexity of installation.

Why Roof Insulation is Important

Roof insulation improves the overall comfort of your home, lowers energy costs, and can even protect your roof from molds and moisture damage. To ensure you’re choosing the suitable roof insulation material for your needs, remember the following:

  • Consider your budget. It determines what type of material you can go for.
  • Refer to the Energy Map for a rough idea of the R-value you need for your home.
  • Consult the professionals to get an accurate quote for roof insulation installations.

Installing roof insulations is a huge investment. Ensure that the professionals handle it. Get a free quote from Trenton Roofing today!


Alex Valentino

Alex Valentino – Vice President

Leading the way for the company’s second generation of family and employee ownership, Alex’s mission is to create lasting relationships built on trust and respect by providing uncompromising workmanship and unparalleled customer service. With a focus on safety and consumer education, Trenton Roofing strives to set the bar for the advancement of the roofing industry and the betterment of our local communities. When he is not working, Alex can be found traveling with his fiancée, watching football or playing a relaxing round of golf with his friends.