What Type of Insulation is Best for My Attic?

Last year, your feet were always cold. You’ve decided to take action. Your attic is the place to start. But what type of insulation is best for your attic?

Winter is coming. It isn’t uncommon to see the first flakes of snow in October in the midwest. 

Be ready to bundle up this coming season. Get your layers: sweaters, jackets, vests, coats. 

But you shouldn’t need to bundle up indoors. Let your attic wear the layers, and you will stay comfy in your home without always reaching for a sweater. 

If you’re ready to invest in your comfort at home, reach out to SoDak Insulation for an inspection or estimate today. We’ll walk you through your options and offer solutions fine-tuned to your home.

How Does Insulation Work?

Regardless of the type you choose, insulation works by preventing the transfer of heat. 

insulation material like fiberglass or cellulose

Think of a thermos. It will keep the heat inside when you fill it with coffee. It keeps the heat out when you fill it with lemonade. 

The thermos is blocking the movement of heat in both cases. Likewise, the insulation in your attic keeps your home’s heat inside while keeping the exterior heat out.

Have you ever been disappointed in a thermos? You were planning on a nice, hot chili for lunch. But when you opened your container at noon, the contents were barely warm. You just experienced the effects of inadequate insulation. 

You don’t want your house to be like lukewarm chili.

The thickness of your insulation matters, but the kind of insulation you choose matters even more.

All types of attic insulation have an R-value. R-value is a measure of how well the insulation material prevents heat loss. 

As you consider what type of insulation is best for your attic, you’ll need to know the ideal r-value to add. In a cold climate like South Dakota, plan for a total R-value of 60. This will keep your home cozy all winter long.

What Type Of Insulation Is Best For My Attic? 

Proper insulation improves comfort levels and energy efficiency. Adding insulation is a relatively inexpensive improvement with a big payout in comfort as well as lower utility bills. 

Let’s take a look at some common types of insulation for your attic.

builder installing or removing old insulation

Fiberglass Insulation

Fiberglass insulation is the pink stuff most people think of when they hear the word insulation. Molten glass is spun into fibers, like a glass cotton candy.

This type of insulation is available in rolls or batts that are easy to lay between the floor joists. 

Fiberglass insulation has several advantages to consider:

  • It’s inexpensive. When estimating the cost of adding R-value, fiberglass can give the biggest bang for your buck.
  • Insects don’t eat it. Fiberglass has no nutritional value, so insects are not drawn to it. 
  • Blanket fiberglass insulation can be installed without any special tools. It just needs to be rolled out to cover your attic space.
  • It doesn’t burn. 
  • Faced insulation (the kind that comes with a vapor barrier on one side) is resistant to moisture and mold.


Fiberglass insulation has some disadvantages to consider, as well:

  • It’s itchy. If you’re planning on installing this yourself, make sure to cover all of your skin. Wear a dust mask to protect your lungs. The tiny shards of glass that make up fiberglass can leave you feeling itchy or scratched up if it touches your bare skin. If you inhale them, they can cause lung disease.
  • It doesn’t seal at the edges. Like a blanket that isn’t tucked around your feet, fiberglass batts can leave a gap where it meets the walls of your attic. You can try to squash it in those spaces, but fiberglass insulation only works well if it isn’t compressed. 

Blown-in fiberglass doesn’t have this problem.

  • It will eventually lose its fluff. Insulation works by trapping air. Fluffy insulation holds more air in place, so as fiberglass batts settle and sag over time, its efficiency decreases. 

Fiberglass is also available in loose-fill, which is blown in with a machine. This job is best left to professionals. 

loose fill fiberglass insulation for attic


Cellulose insulation is made from recycled paper, making it an eco-friendly choice. This loose-fill insulation is blown in with a machine, making it easy to reach those edges where your attic is too short to stand. 

Here are a couple of pluses about cellulose:

  • It’s environmentally friendly. 
  • It fits in tight spaces. The blown-in cellulose works neatly around ducts and wiring.
  • Cellulose is fire-resistant. It’s coated with boric acid and is considered safe. 
  • Insects won’t eat it. 

Here are some of the downsides:

  • Settling. Like fiberglass, cellulose has a tendency to settle over time. As it ages, it becomes less efficient.
  • It has the potential to mold. Cellulose will soak in any moisture quickly. If there are any moisture issues in your attic, cellulose will quickly mold.

Cellulose may be the best type of insulation for your attic, but you definitely want to correct any moisture problems before installing it.

Foam Insulation

Spray foam insulation comes in two forms.

Closed-cell foam has a higher density and a higher R-value. It also is more resistant to water penetration. 

Open-cell foam has a lower R-value. It expands as it’s applied, making it a good choice for hard to reach areas. 

Open-cell foam is permeable to water and air. It should only be used for small fill in spaces. 

Closed-cell spray foam has some excellent advantages:

  • It expands quickly to create an airtight barrier around gaps and crevices. 
  • Spray foam doesn’t soak in water, and it doesn’t let water pass by. If you do have water penetration in your attic, spray foam has the best chance of holding up to it.
  • It lasts. Unlike many other options, spray foam does not settle over time. 
  • It’s a great sound dampener. Spray foam helps absorb sound waves that might otherwise echo around your house. 

The downsides:

  • It costs more than other options. 
  • You’ll need a professional to install it.
  • It can’t be added to other types of existing insulation. If you’re just looking to beef up the R-value in your marginally insulated attic, this may not be the best type of insulation.

The Best Choice Will Keep You Happy For Years To Come

So, what type of insulation is best for your attic? It’s the kind that leaves you and your home the most comfortable. 

Contact SoDak Insulation today to get more information about the best attic insulation plan for you. We can give you options that won’t leave you out in the cold. 


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