How to Choose the right insulation material for your home?
The full guide for making an effective decision
When it comes to insulation there are many material types and brands you can choose from and often times it can get very confusing, however choosing the right insulation for your home can be an easy decision once you get familiar with the basics.
After installing different insulation materials in over 7000 homes throughout the US, we learned that some materials could be perfect for one home structure but for others it can become a disaster over time. Our goal with this guide is that you will be able to make an effective decision choosing the right insulation for your home considering price, material type and thermal efficiency.
Is your attic well insulated?
The U.S. Department of Energy recommends homes in southern climates to have 13-14 inches (R-38) of insulation and 16-18 inches (R-49) in northern climates, however, according to the Insulation Institute, over 90% of homes in the United States are under-insulated.
This is rather unfortunate that local building codes only stipulate minimum performance standards, which are far below what home energy experts recognize as necessary today. That means that unless you’ve recently had an insulation upgrade, your attic is likely to have an inadequate amount of insulation and you are losing money dealing with uncomfortable, uneven temperature in your home.
Homeowner insulation guide
Insulation is made out of different materials and is installed in various methods. The most popular materials installed in residential homes are batt insulation and blown insulation (loose fill).
When considering material type or method of installation we highly recommend to get an attic and crawl space inspection first because the structure of your home might require a specific method.
For example if your attic clearance is less than 3 feet you will only be able to install blown insulation, since installation of batts isn’t physically possible in low clearance attics.
To read more about how to choose the right insulation material based on your home structure please click here.
What is batt insulation?
Batt insulation is simply a pre-cut panel, which comes in different standard sizes and R values directly from the manufacturer to comply with general construction codes. Batts are essentially felt pieces designed to fit between the framing of the home (usually 16 or 24 inches on center)
Some batt insulation comes with paper or foil facing to control moisture issues, these are known as “faced” or “kraft” insulation. Faced insulation is commonly installed inside walls because the paper that absorbs the moisture is often flammable and therefore by code, in some cases, isn’t allowed to be installed in exposed walls, attics or crawl spaces.
Batts are sold in a variety of R-values (thickness) and depending on the climate of your area you may need more than one layer to maximize energy savings.
Batts insulation installation requires trained workers who can fit into the space you are trying to insulate. For homes with attics or crawl spaces that are inaccessible, batting insulation might not be a viable option and you will then need to consider blown insulation as an alternative. Blown insulation is applied by a specialized machine that “shoots” the insulation and therefore it will be easier for the material to settle in very small harder to reach areas.
What is blown (loose fill) insulation?
The term loose-fill insulation or blown-in insulation refers to the process of filling stud or joist cavities with insulation in the attic or walls. This process is done by a machine that mixes the material and shoots it through a hose creating an evenly insulated surface
Loose-fill insulation is essentially millions of insulation pieces who creates air pockets which assure better insulating power. Since the pieces are tiny and are blown everywhere it is possible to cover small areas with difficult access and therefore this method is known to be a fantastic thermal barrier.
Unlike batt insulation, blown insulation doesn’t come with a specific R value so the more material you blow the higher the R value. Insulation contractors usually use an insulation ruler to ensure the correct R-value has been installed.
What is R-value?
Technically speaking, R-value is a measure of an insulation’s resistance of heat/cool air flow traveling through it. So essentially it would make sense that the higher the R-Value of your insulation, the greater the resistance, however that is only one factor that determines the effectiveness of insulation, and only one aspect you should look at when making your decision on which insulation is best for your home. R-value is the industry standard for measuring the resistance value of specific insulating materials. The higher the R-value, the better the material insulates.
If we look at the primary purpose of insulation- it is used to block the movement of heat. Heat is a force that moves in and out of your home in 4 ways, but the only one measured by R-Value is Conduction. The other 3 ways we must consider are sun radiation, air infiltration, and convection.
Since your home is built outside- factors such as humidity, temperature shifts, and wind all come into play and directly affect the indoor air quality.
Batts or blown?
Tips for choosing the right insulation based on your home structure?
It is important to understand that manufacturers and insulation contractors may not always give the best recommendation regarding which insulation you should install- that is simply because they are missing important details about the structure of your attic or crawl space.
We recommend about 95% of our customers to install batt insulation and here is why:
1. Accessibility and easy to service
We believe our customers need to have easy access to all the unfinished parts of their home because the most important systems are located in these areas. These include your home’s HVAC, plumbing, central vacuum, air ducts, electrical wires, recessed lights etc.
If one of your systems malfunctions, you will need to call a professional and if you will not have easy access it might take longer to fix or in some cases will not be possible at all.
Some of the issues that can arise include the following:
The HVAC system needs to be serviced and all the wires are covered with blown insulation.
- The dryer vent got disconnected
- One of the recessed lights stopped working and the electrician cannot locate it because it is covered with blown insulation.
Our best example is of a customer who called an HVAC company to replace his air ducts. It was almost impossible for the crew to see where to step since all the studs were covered with blown insulation and one of the guys ended up putting his feet on the sheetrock, losing his balance and falling through the attic floor straight down into the bedroom.
In other cases where you need to service one of the systems in your attic, a service professional will have to move/vacuum some of the blown-in insulation in order to have better visibility and complete his task. Once that has been done, it will be impossible to bring the insulation back to its original state, and in many cases the service professional will leave you attic with uneven, damaged insulation, lacking the R-value it previously had. Unfortunately for you as a homeowner, there is not much you can do to prevent it, because it will be crucial for the professional to complete the repair.
2. Storage friendly
If you have a spacious attic you might want to store items like boxes, suitcases and christmas decorations. Batt insulation will help you to keep your items clean, safe, and easily accessible.
3. Effectiveness over the life of the building
It is true that blown-in insulation is considered to be more effective as a thermal barrier, however, this effectiveness is only temporary and will not last for the life of the building. Most blown-in insulation materials will settle and lose R-value over time. Cellulose, which is one of the most popular insulation materials used today, has the tendency to absorb water over time and will cause the insulation pieces to bond. This will have a direct negative effect on the effectiveness of the insulation.
4. Rodent activity (past or current)
If you have rodent activity we highly recommend you not to install blown-in insulation. It is easier for rodents like mice, rats, squirrels and raccoons to nest in blown insulation and its harder for you to identify and fix the issue. Blown-in insulation will make it harder to install a baiting station and find access points that are naturally created by rodents when trying to find shelter and warmth inside your attic insulation.
It will also be two times more difficult and expensive to treat blown-in insulation that was affected by rodents than treating batt insulation and this is why- let’s take a scenario in which only a small part of your insulation got damaged. With batt insulation it will be easy to identify and replace the damaged part. You can even do it yourself on a sunday. If rodents damaged your blown-in insulation its will be impossible to replace only a small part and you will be required to get professional help. You will need to hire a company who specializes in insulation removal and has a heavy-duty vacuum and insulation machine. In many cases you will end up replacing all of your attic’s insulation spending thousands of dollars.
When it comes to insulation materials we recommend that you consider only the ones that have been thoroughly tested in the United States. There are many new materials that claim to be eco-friendly, green and healthy for you but will not last for the life of the building. Bottom line – if it hasn’t been around for long and wasn’t tested over time we recommend you not to choose it.
The 4 insulation materials you should consider are Fiberglass, Cellulose, Mineral Wool (rockwool) and Polyurethane Spray Foam.
Here are some pros and cons of each material:
Fiberglass is by far one of the most thoroughly tested building materials and can be installed in the form of batt or blown-in insulation. Fiberglass is eco friendly, non-flammable, safe to install and maintains its thermal performance for the life of the building. One of our favorite brands for fiberglass insulation is Owens Corning (the pink panther insulation company). They have been in business since 1935 and are sold in almost all of the reputable home improvement retailers such as Home Depot and Lowes.
A great tip every homeowner should be aware of is that Owens Corning is a manufacturer that goes the extra mile- certifying licensed contractors, giving them periodical training and even visiting job sites as quality assurance making sure the insulation service is performed correctly. Hiring an Owens Corning Certified Energy Expert (CEE) is very important when selecting a contractor to perform insulation services for your home- it simply assures you that the job will be done correctly and to the highest standards. To find a certified energy expert (CEE) contractors in your area go to owens corning website.
Cellulose insulation is one of the most popular materials for residential and commercial buildings. It is made out of recycled newspapers and is chemically treated with ammonium sulfate for fire resistance. Cellulose has a great thermal performance, however it is regulated as a fire hazard by the Consumer Product Safety Council (CPSC) because it is made out of shredded, recycled newspaper.
Tests conducted by the Bureau of Home Furnishings and Thermal Insulation have demonstrated that some cellulose samples failed the standard fire safety test only six months after installation.
It is also important to note that the installation process of cellulose is very messy. Cellulose is very dusty and during the installation process can be dangerous because it may leave residue behind (fiber, dust and chemicals) and can be an irritant.
To avoid dust as much as possible, prior to installation, make sure the working area is protected with a plastic tunnel and all the recessed lights are covered in order to prevent particles from entering the living space.
A few more facts to consider when choosing cellulose:
- Cellulose manufacturers agree that their products will settle over time so basically you will be losing R-value over time and will have to add more insulation in the future.
- Cellulose absorbs water and becomes heavy over time – high risk for cracks in the ceiling and drywall sagging.
- Cellulose is probably the cheapest insulation material available today.
To summarize, you can find many articles that will be for or against cellulose. At the end of the day, based on our experience, cellulose could be a good option for your attic because of the cheap price and the thermal benefits, however, when choosing this material make sure you are not allergic to ammonium sulfate and be ready to do some cleaning.
Mineral Wool (rockwool) Insulation
Mineral wool is made out of natural rock and is widely used in Canada and Europe. It is made by melting down basalt stone and recycled slag from steel mills, then spinning it into fiber that can be formed into batts or boards.
Here are the pros and cons:
Price: Mineral wool batts cost more than fiberglass batts. As an example, the R-19 mineral wool costs about 90¢ per sq. ft. vs. 70¢ for fiberglass.
Fire resistance: Mineral wool withstands extreme heat better than other types of insulation. In a fire, the batts retain their shape and offer better protection against flame spread.
Water-resistance: Mineral wool insulation just like fiberglass insulation does not absorb water. This means that if your wall or roof leaks, the batts will be as good as new after they dry out. Cellulose on the other hand, will absorb water and as a result will need to be removed entirely and have new installation installed to restore the R-value.
Sound barrier: One of the greatest properties of mineral wool is that the material is great in blocking sound. Many contractors are using it as a barrier between floors or around the machine room in the basement for that reason mainly. To read more about sound proofing check out this great article: https://www.soundproofingtips.com/soundproofing-insulation/
Polyurethane Spray Foam Insulation
Spray foam insulation uses 2 chemical compounds that expand when mixed together and simultaneously air seal and insulate the application area.
Spray foam is the most effective insulation available, however it is probably 2-3 times more expensive than the rest of the alternatives. If you consider to insulate your attic or crawlspace it will be hard to beat the quality of spray foam because it outperforms other insulation materials in terms of R-value, resistance to mold and moisture damage, durability, air sealing, and versatility.
Advantages of spray foam
- Best R-value per inch.
- Very effective in Stopping air leaks in addition to providing insulation value
- Won’t compress, fall out of place or lose R-value.
- Closed-cell spray foam is waterproof & won’t support mold growth
Disadvantages of spray foam
- 2-3 times more expensive than fiberglass for the same R- value
- If not installed professionally and chemicals are not mixed evenly the material might not “cure” which means you will not be able to stay in the house until that has been treated.
- You can not be at home during installation.
- High risk for damages – every drip of the material is irreversible since the foam is like glue.
Open-cell vs closed-cell spray foam insulation
There are two types of spray foam insulation: open-cell and closed-cell. Each has different features, pros and cons. A professional will help you determine the best foam for your needs.
Open-cell spray foam
Open-cell foam is a very light material that is designed to break or pop as the foam expands before it sets, allowing pieces to be removed. Open cell foam is low density and can fill larger areas with less material, and it has an R-value of 3.5-4 per inch.
On a cost-per-R basis, open-cell is the more economical spray foam choice. However, it is not as effective as closed-cell spray foam.
Closed-cell spray foam
Closed-cell spray foam is the most energy efficient insulation available today and it provides an R-value of 6-7 per inch. After being applied, the foam cures and hardens like a rock- providing great air sealing and building support.
Insulation installation tips
The do and don’t when insulating your attic or crawl space
Blow insulation on top of existing insulation
DON’T. When you cover old insulation with new it is only a matter of time until you will need to remove both. When taking this “band-aid” approach your contractor is likely to cover existing issues and hazards such as rodents, exposed electrical wires, bacteria, mold and more and you must avoid it. This is a common wrong practice of the trade a lot of contractors do because it’s either easier or they do not have the right equipment for insulation removal.
Remove and replace insulation by yourself
DON’T. Old insulation must be removed by a professional contractor. Old insulation is considered to be a hazardous material and must be removed and disposed of in a certain way with professional gear and trained workmanship. In order to protect yourself, your home and your family call a professional insulation removal contractor first. Amongst other risks, the main issue is that unsafe removal can release hazardous particles into your home affecting the indoor air quality and the family members living in it.
Enter the attic without protective gear
DON’T. You can get sick even when entering an attic or crawl space for a very short amount of time without proper equipment. These unfinished areas of your home are exposed to bacteria, fungus from rodent infestations, mold and other hazards that are toxic to inhale. We recommend eye protection goggles, coveralls, a half-face mask, a head-light and gloves to keep yourself fully protected.
Touch/rub insulation against your skin – The itch factor
DON’T. Fiberglass and mineral wool can be itchy or even cause a mild rash. Regardless of which material you install, be sure to wear a dust mask, goggles, gloves and a long sleeve shirt to make sure particles do not irritate your skin or cause any allergic reaction.