Homeowners Attic Insulation Guide

If your home has poor insulation, then you’re losing money to a high energy bill. Like the rest of the exterior surfaces of your home, it’s a wise choice to insulate your attic to ensure that heat doesn’t escape during the winter. Plus, you’ll help to keep cool air inside of your home throughout the summer. The benefits of insulation don’t stop there. In today’s blog, we’re going to note a few of the reasons why you should get attic insulation, and we’re going to address your insulation options, as well as some frequently asked questions that we often encounter from our clients. As always, you can count on the crew here at Rock Solid Exteriors to provide you with attic insulation services alongside our roofing services — we provide service for our neighbors throughout Macomb, Oakland, Wayne, and St. Clair Counties from our workshop here in Mount Clemens. Now let’s dig in, starting with the benefits of installing insulation.

The Benefits of Insulation

As we mentioned, the biggest benefit of insulation is energy cost reduction. Beyond that, insulation will improve the value of your home, and it will reduce your impact on the environment by making your abode a little bit more eco-friendly.

Seasonal Energy Costs

Your attic can prove to be the perfect space for climate-controlled air to escape your home, especially in the winter. When you’re heating your home, all of that heat will tend to rise toward the ceilings of your space. As it makes its way up through the vertical space of your home, this heat may end up seeping into the attic of your abode, where it will escape to the outdoor air — that is, unless you insulate your attic. Folks opt to insulate their attic space to add some r-value (a unit measuring the resistance to transfer heat between surfaces) to the envelope of their home. The attic may otherwise be one of the weakest places in a home, where heat can easily escape in winter and precious cool air can leak out in summer.

Improved Home Value

While you may not have thought about the attic much as you bought your current home, the attic should be part of the inspection process, and an insulated attic will add value to a home that is being placed on the market. Adding insulation to your home won’t just improve your seasonal energy costs, it will also add lasting value to your home, which means that you’ll earn much of the money that you invest in your property, should you ever decide to sell it. Factor that in with the savings that you’ll enjoy on your monthly energy bills, and your attic insulation will eventually pay for itself!

Lower Carbon Footprint

Every time that furnace turns on, you’re using energy. If you want to reduce your impact on the environment, then an investment in attic insulation can help you to ensure that your home is “green.” Since heat and cooled air will be less likely to escape your home day in and day out, your home temperature will remain a bit more stable, and your furnace and AC unit won’t have to click on as often. Again, that means less energy expenditure for your home, and a lower carbon footprint.

Insulation Options

If you’re considering insulation for your attic, you’ll have to weigh all of the material options out there to determine the best choice for your attic, your budget, and the constraints of your property. Here’s a quick overview of the insulation materials available to homeowners today:


What it is: Cellulose is a common insulation material because it is relatively inexpensive. Cellulose is simply recycled paper and wood material that can be used to insulate your attic space. Most cellulose products are treated with insect-repellant and fire-resistant chemicals since cellulose could otherwise be a problematic addition to your house.

Characteristics: Cellulose is cheap but it may be vulnerable to mold if moisture makes its way into your attic — make sure your roof is in tip-top shape before considering this option. Cellulose also has a great r-value, ranging from 3.2 to 3.8 per inch.
Blow-in or batts: Cellulose is available in both blown-in and batt versions, making it convenient for most attic spaces.


What it is: Fiberglass is just that, glass that is spun into fibers. This material has long been a common attic insulation material.

Characteristics: Fiberglass is lightweight and easy to apply. However, you need to be wary that protection must be worn when working with this material, since it can agitate the skin or lungs. Fiberglass also settles more than other materials so you may need to apply a few extra inches of fiberglass to keep your attic insulated. Fiberglass has a decent r-value of 2.2 to 2.7 per inch.

Blow-in or batts: Fiberglass is available in both blown-in and batt versions, making it convenient for most attic spaces.

Mineral Wool

What it is: Mineral wool is similar to fiberglass in a lot of ways and it’s actually made of fibrous material produced from either rock or recycled waste product from blast furnaces.

Characteristics: Mineral wool is a slightly costlier option than the others previously listed, but it is naturally resistant to fire. Mineral wool has a great r-value at 3.0 to 3.3 per inch.

Blow-in or batts: Mineral wool is available in both blown-in and batt versions, making it convenient for most attic spaces.

What it is: Cotton batts are created from recycled cotton materials.

Characteristics: Like cotton clothes, cotton insulation naturally blocks the flow of air and it may damper sound. However, this material is more expensive than other options, and a bit trickier to install. Cotton has an excellent r-value of 3.7 to 3.8 per inch.

Blow-in or batts: Cotton is only available in batt form, which means that you should only install it if you have an attic with evenly spaced joists. Most batts are available in 24-inch or 16-inch widths.

Spray Foam

What it is: Spray foam is an expanding, sticky applicant that is sprayed on surfaces to provide insulation.
Characteristics: Spray foam is unique as an insulator, since it sticks where it is applied. This makes spray foam useful for oddly spaced attics and attics with joists that are uneven. Spray foam has the best r-value, which may be as high as 6.5 per inch. However, spray foam is the most expensive option.
Blow-in or batts: Spray foam isn’t blown in, nor is it available in batts. This specialized foam insulation is sprayed directly on the surfaces of your attic that require insulation, where it will expand and remain in place.

Attic Insulation FAQ:

Does insulation help in both summer and winter?

Yes. Attic insulation helps to keep heat from seeping through the ceiling of your home’s uppermost floor, and it aids in preventing cold air from dissipating through your attic. Attic insulation is especially important in colder climates, since heat rises and escapes quickly through attic spaces that are unprotected.

Should I add attic insulation between the rafters of my attic?

It depends. Most attics do not require insulation between the rafters since this insulation won’t be necessary. Usually, insulating the joists at the floor of an attic is ideal for keeping a home’s climate controlled. You can achieve a high enough r-value by simply insulating the joists.

Adding a second layer of insulation to the rafters is redundant, and may often be problematic, since it can block vents throughout the attic structure, which may help to remove moisture from the attic while providing a slight cooling effect for the attic during summer. You should only install insulation in the rafters of your home if you have a finished attic, or plan on finishing the attic to make use of its space.

Should I opt for blown-in insulation or batt insulation?

It depends. While both insulation types are effective, each has its own benefits. Blown-in insulation is best for oddly shaped attics, since it can be blown into awkward, hard to reach spaces. In addition, blown-in insulation can be added as necessary, so you can fill an attic to your desired r-value rating. Batt insulation is ideal if you plan on using your attic space, since it fits between the joists. In addition, it has a higher r-value per inch, but blown-in insulation can compensate for that factor with additional inches of insulation.

How long will my insulation last?

Insulation lasts for a long time. Most insulation can last about 100 years. Spray foam insulation lasts about 80 years.

Protect Your Home With Rock Solid Exteriors

If your home is overdue for an update with energy-efficient attic insulation, then we’d be happy to help. Count on the crew here at Rock Solid Exteriors to provide you with insulation services that will lower your energy bills month after month. Reach out to us to schedule an appointment — again, we provide home exterior services throughout Macomb, Oakland, Wayne, and St. Clair Counties from our home here in Mount Clemens.


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