Best Type Of Insulation For New Home Construction

Whether you're building a new home or work regularly in the construction industry, you want to know about the types of insulation for new homes. Which insulations are best? Are there areas where certain insulations should not be installed? Can a general contractor handle some insulations?

South Central Services has insulated hundreds of homes with spray foam. Our team works with batt, blown-in, and spray foam insulation for new construction houses. Every insulation recommendation we make is rooted in building science and what a home needs to be comfortable and energy-efficient.

By the end of this article, you will understand:

• What insulations are available for new home construction
• Where each type of insulation is generally installed
• Where we recommend each kind of insulation, and why

Insulations Available For New Home Construction

Most insulation products are available for new home construction. When building a new house, the canvas is wide open for air-sealing and insulation. In southern Pennsylvania, these are the insulation products that we see most frequently.

• Batt
• Blown-in
• Dense pack
• Spray foam

Let’s examine each of these insulation types in more detail.

Batt Insulation Used In New Home Construction

In new home construction, batt insulation can refer to fiberglass, cotton, or rockwool batts. The type of material will determine the look of each batt. For example, fiberglass batts tend to be cotton candy pink. Rockwool batts are often gray or yellow. The material of the batt can also influence its performance.

Batt insulation is a thick blanket of insulation made of heat-resistant materials and cut to various sizes. To be most effective, batt insulation must fit snugly in a cavity and fill it entirely.

Where Batt Insulation Is Commonly Used In New Home Construction

Batt insulation is popular for new construction because it is less expensive than other insulation types. When building a new home, looking for areas to save costs is natural. Most general contractors are able to install batt insulation on their own without outsourcing to another contractor.

In the average new build home, batt insulation could be found in the basement ceiling, exterior walls, interior walls, floors, and attic.

Where We Recommend Using Batt Insulation In New Homes

At South Central Services, we install batt insulation in the interior walls of new construction homes. Batt insulation is best for this application because of its low cost and sound attenuation properties. You can limit sound transfer between rooms by filling your interior walls with batts.

You can also install batt insulation between floors that are not a part of your thermal envelope. While batt insulation is inexpensive, it is not the best-performing insulation. Any area of your home that will be part of your thermal envelope should have high-performing insulation.

Blown-In Insulation Used In New Home Construction

In new home construction, blown-in insulation can refer to cellulose or fiberglass insulation. Blown-in fiberglass is made of the same material as fiberglass batts but is in a loose fill form. Cellulose insulation is composed of recycled paper material. Both materials resist conductive heat transfer.

Blown-in insulation is a loose insulation material. Unlike batt insulation, which is packed into cavities, blown-in products are piled onto flat surfaces.

Where Blown-In Insulation Is Commonly Used In New Home Construction

The most common use of blown-in insulation in new build homes is on the attic floor. The nature of blown-in products limits its possibilities for application options. Over time, blown-in insulation settles and requires being "topped off" to remain effective. As such, a loose fill product should not be put in a wall because the insulation will eventually settle.

Where We Recommend Using Blown-In Insulation In New Homes

South Central Services does not recommend blown-in insulation in new construction homes. Blown-in products are limited to attic applications, but your attic is part of your thermal envelope. In fact, the attic can contribute to 30% to 70% of your energy efficiency.

Blown-in insulation in the attic is better than no insulation at all. However, blown-in performs better when paired with an appropriate air seal.

The best performance available is spray foam insulation. An attic with spray foam will perform better than blown-in can, even with an air seal.

If you choose blown-in insulation for your attic, we recommend air-sealing the attic floor first. An airtight seal maximizes the performance of insulation. You will also need to monitor the insulation for settling. However, the best scenario for your attic is to invest in high-performing insulation that doesn't require maintenance or separate air-sealing products.

Dense Pack Insulation Used In New Home Construction

Dense pack insulation refers to a type of loose fill cellulose insulation. As the name suggests, dense pack insulation tightly packs insulation into wall cavities. Dense pack insulation involves recycled paper material and some netting to hold the blown cellulose in place.

Where Dense Pack Insulation Is Commonly Used In New Home Construction

Dense pack insulation is generally used in the same areas that batt insulation is used. However, there can be some limitations to dense pack applications due to the nature of its installation.

Dense pack is most commonly used for exterior and interior walls in new construction homes.

Where We Recommend Using Dense Pack Insulation In New Homes

Dense pack cellulose insulation is an option for exterior walls. We always encourage homeowners to seal their homes from uncontrolled air infiltration. Exterior walls make up part of the thermal envelope and need an airtight seal. Dense pack insulation can offer this air-sealing capability when installed properly.

Like batt insulation, dense pack cellulose can be used for sound control. We recommend dense pack for interior walls. However, many contractors who install dense pack in new build homes would also encourage you to insulate the exterior walls with the same insulation.

In our opinion, dense pack insulation is not as effective as spray foam insulation for exterior walls, but it is significantly more effective than batt insulation.

Spray Foam Insulation Used In New Home Construction

For new home construction, spray foam insulation can refer to either open cell spray foam or closed cell spray foam. Which type of spray foam to use depends on the application type and the home's location.

In southern Pennsylvania, closed cell is a more versatile insulation and is used more frequently in new construction homes. Further south in different climate zones, open cell becomes more useful.

Where Spray Foam Insulation Is Commonly Used In New Home Construction

Spray foam insulation can be used in almost any area of a new build home. However, where homeowners choose to install spray foam varies on a case-by-case basis. Some homeowners want spray foam insulation in every applicable area of their home. Others prefer to pick and choose specific areas, such as their underslab foundation or roofline.

Depending on the type, spray foam insulation can be installed in basements, exterior walls, attics, crawl spaces, foundations, and in-between floors.

Where We Recommend Using Spray Foam Insulation In New Homes

South Central Services recommends spray foam insulation for any area of your home that is part of the thermal envelope. Your thermal envelope is the barrier between your home environment and the outside world.

Spray foam insulation is the only new construction insulation that offers an airtight seal. This air barrier allows spray foam to stop both conduction and convection heat. The other insulations we have discussed only prevent conductive heat transfer. Heat from the air can transfer randomly through air leakage.

We advise using spray foam in your basement, attic, and exterior walls. If your new home also includes a crawl space, we recommend encapsulating that space. Encapsulation creates easy access, improves indoor air quality, and lowers energy bills.

Below-Grade vs. Above-Grade Applications

Open cell spray foam is only an option for above-grade applications. This includes your exterior walls, attic, in-between floors, and basement ceiling.

Closed cell spray foam is approved for above- and below-grade applications. If you want to insulate your basement walls instead of the ceiling, or if you have a crawl space, closed cell is the only spray foam option. Closed cell can also be used everywhere that open cell can be used.

The Bottom Line About Which Insulations To Use In New Homes

When insulating a brand-new home, you will use multiple kinds of insulation. New construction homes are open to insulate every area, but not every area of the house has the same goals.

We recommend an airtight seal for exterior areas of your home. If air breaching that area of your home could cause temperature fluctuations from the outside world, you want an airtight seal.

We recommend batt insulation for interior areas of the home. Air can exchange randomly from room to room without wreaking havoc on your HVAC system. Instead, the greatest concern for interior walls and in-between floors is stopping sound transfer.

Now that you understand the best insulation choices for your new home, your next step is to:

• Learn the best way to insulate a new house
• Compare the cost of closed cell and open cell spray foam
• Decide if you want to work with South Central Services