Attic Insulation Guide: How to Find the Best Attic Insulation

Best Attic Insulation

Summer is always hot–but this summer may be one of the warmest yet–which is all the more reason to invest in the best attic insulation possible to keep your house cool.

As it so happens, it’s shaping up to be one of the warmest summers globally, with Europe recording a record heatwave for June. Recorded temperatures measured 0.2 degrees Fahrenheit before the previous record; one town in France reached an astounding one hundred and fifteen degrees Fahrenheit, a record for that location.

My Top Pick: Dow Froth Pak 650, Spray Foam Insulation Kit
Spray foam is water-resistant, pest-resistant and honestly, it's best type of installation for attics. Our top recommended product is the Dow Froth Pak 650, Spray Foam Insulation Kit - it comes with plenty of foam and nozzle versatility.
Check Price
We earn a commission if you click this link and make a purchase at no additional cost to you.

In the same country of France, a four-day heatwave turned deadly, killing seven people and causing wildfires to spread. In the United States, half a dozen states in the upper Midwest were under heat advisories for the final weekend of June.

While heatwaves are not an uncommon phenomenon during summer months around the world, some scientists have estimated that heatwaves are now five times as common in Europe than they were in the past, and that trend, while not entirely even worldwide, seems more or less an accurate picture of increasingly common days so hot that can pose danger to those working outside.

Fortunately, simple precaution and common sense can go a long way. And you don’t have to crank your air conditioning high in your house to stay cool, either. The best attic insulation is a way to save money, stay cool, and protect your house (and keep it warm during the winter).

But while most people know attic insulation is important, many do not know much about it.

Here’s an easy attic insulation guide so you can have your best year yet. It may very well be the best home improvement you make.

How do I know if my home needs more insulation?

You may be surprised to learn that as much as ninety percent of homes of under-insulated in the United States–while that is according to the Northern American Insulations Manufacturers Association and could be slightly slanted, there is little doubt that many homes are not properly insulated.

There are several ways to tell if your attic is not adequately insulated, including:

  1. Increasing, or excessively high cooling and heating bills. Heat and air conditioning escape through poor, thin, or damaged insulation, leading you to lose heating and air conditioning more quickly. That means higher bills, too. So if you notice your bills climbing for no other reason or find yourself constantly adjusting the thermostat, you may have inadequate attic insulation. To tell if it’s your attic causing the issue, you can have someone inspect it or inspect it yourself. If you feel much cool or hot air escaping, the chances are that it’s time to invest in new attic insulation.
  2. Frozen pipes. While frozen pipes do not always indicate improper attic insulation, they do indicate that there is an insulation problem somewhere. Again, having a professional come out and inspect is a good way to tell where that is, but often if there are insulation issues in one area, it’s possible there may be issues overall.
  3. Water leaks. A clear indicator of attic insulation problems in the attic is when you come across water leaks. Water enters homes with poor insulation and is a problem that should be addressed as soon as possible. Water leaks, of course, can lead to water damage. You can also tell there have been leaks by the presence of mold and mildew.
  4. Many bugs, mice, and other invaders in your house. Mice come into houses, and insects do as well. But if there is a rise in these invaders, there is a chance it’s due to poor insulation, which gives them more places to enter the home.
  5. Drafts and cold rooms. Again, drafts and cold rooms are signs that you have poor insulation. If it seems to be coming from the attic, then chances are it’s time to invest in better insulation.

What do you need to do before you prepare for attic insulation?

One mistake that many homeowners make is using the attic for storage. While it’s understandable that many would see attics as useful for storage, it doesn’t spell well for insulation. Not only is it more likely that the insulation will become damaged, but it also leaves less room for adequate insulation.

Beyond that, there are certain steps you need to take to prepare your attic for insulation:

  • All old insulation should be removed first. In addition, it’s important that any leaks are sealed. Failure to do so means you’re simply laying more insulation over what will be a problem in the long run. That isn’t to say you always have to do this if the older insulation is in good shape–but if it’s not, this is a critical step.
  • Make sure there is adequate ventilation. Typically in an attic, there should be eaves to the house that allow air to escape. Make sure those are not covered and that air can flow freely. This also ensures that moisture can escape and helps prevent water damage. Ventilation chutes are also helpful if there is not much airflow.
  • Take some time to address electrical wires, and ensure they are safe from any water or damage. You should properly protect all wires before insulation can begin. Keep in mind that insulation should never be placed on electric wires. In fact, you should allow a few inches to ensure safety.
  • Seal off any air leaks. Air leaks typically occur near attic doors and steps. You can accomplish this by simply adding a weather strip near these key areas.

What problems can occur if my attic is not sufficiently insulated? 

Improper insulation can, of course, lead to heat loss, but there are even more problems that can occur if you don’t invest in best attic insulation practices. Frosting, rusting, water damage, and other problems can cause long term consequences.

Improper attic insulation can even shorten the life of your roof, by frosting during the winter. That’s why it’s so important to ensure that you have the best attic insulation possible.

Can improper insulation be even worse than no insulation? While it’s debatable what’s more harmful, there is little doubt that improper insulation can cause many problems in your home. If you want to make sure your home is in the best shape possible, just make sure that you take care of foundational elements first. That’s why it’s so important to understand mistakes even contractors make.

What are the most common mistakes made, even by professionals?

Even professionals can make mistakes, which is why it’s so important, even if you are using a contractor, to be aware of the common errors made when installing attic insulation:

  • The attic floor has not been properly sealed. Even if it seems like it has been, all open soffits should be sealed around the edges with caulk; the space between attic floors and chimneys should be closed up with caulk and aluminum, and any open wires need to be properly sealed.
  • Other insulation has not been removed, or there are gaps. While it’s recommended to remove old insulation, at very least it’s important that no gaps exist in whatever is left behind.
  • Half walls are not sealed. Half walls, also known as knee walls, need also to be insulated. For walls made out of fiberglass or cellulose, drywall can be an effective way to complete insulation.
  • Lights are not sufficiently utilized. While it’s important to keep lights at least three inches away from insulation, you waste a good deal of energy. Light fixtures should be airtight and caulked; you can also install fireproof caps.
  • Vents have been covered with insulation. This one is very important, and again it’s a mistake even some contractors have made. If vents are covered, there will be insufficient ventilation.

What are my options for types of attic insulation?

Attic insulation comes in six main types, all of which have pros and cons (which we will discuss later).

  • Loose-fill insulation: Loose-fill insulation is typically made with fiberglass or cellulose, which is a form of recycled paper fibers. Loose-fill insulation is either blown or sprayed in and is typically used to fill individual wall openings and over other insulation. Essentially, this is a-filler insulation for someone who doesn’t want completely news insulation. It’s also favored especially for attics because attics can be hard to reach all corners. Insulation batts: Insulation Batts are another option for attics. Unlike loose-fill, batts are pieces of fiberglass or rock wool and are made sometimes with or without both paper and aluminum facing. This is a favorite option not only in attics but also for floors and walls because the pieces tend to be easier to handle and can be used between a variety of framing.
  • Insulation rolls: Insulation rolls are typically used to be settled between joists and studs and are also a popular option, specifically for attics. You can purchase these rolls in twenty to forty feet increments and are ideal for longer attics.
  • Foam board insulation is hard, inflexible panels of insulation and are not used especially for the attic but considered all-purpose. Typically, the boards are made from some form of polystyrene and or polyurethane and are favored for use with wood and steel.
  • Spray foam insulation, like loose-fill insulation, is used not to completely replace insulation but to fill in any gaps you might have. It is most helpful for acting as a seal on doors, vents, or openings, for example, near an attic ladder. Many people like how easy it is to use: not only does it set quickly, but it also can be trimmed to your liking, and even painted.
  • Vapor Barriers, finally, include house wraps and act as control agents to moderate the levels of moisture. This is not technically insulation but meant to be used to complement existing or new insulation. However, they are more commonly used for home exteriors than they are in attics.

What materials are used for insulation?

 We’ve already mentioned some of the types of insulation, and materials along with it, but let’s take a closer look. Fiberglass, mineral wood, cork, polyetheramine, hempcrete, and refractory materials are all used for various forms of insulation. Of these, fiberglass, cellulose, and foam are all most commonly used for attic insulation. While there is not a single answer to the very best option, let’s take a look at some of the pros and cons of each:

  • Fiberglass, which you’ll find in rolls, loose insulation, and batts, is about and inexpensive as you can get for attic insulation, and it’s also to easier to install yourself or with a general workman.
    •  However, there are a number of problems with this type of installation for attics. Fiberglass is more likely to trap allergens, dander, dust, and more prone to mold and mildew. There is also concern that fiberglass if disturbed, can set off particles in the air that are harmful and can lead to skin and nasal irritation.
  • Spray Foam is especially helpful if you have many hard to reach places in your attic, and unlike fiberglass, it does not retain water, meaning there’s little risk for mold and mildew growth. It’s among the best for reducing electric bills because it provides an airtight seal, and it’s also not attractive to insects or rodents, the way some other materials might be.
    • The downside to spray foam is that it needs to be professionally installed and is initially among the most expensive option. It’s also considered fairly fireproof.
  • Cellulose is the oldest of insulation types and is applied either with loose material or blown in. Boric acid and aluminum sulfate, which are both used, helps prevent mold and pests and is also considered more fireproof. Because it is blown in, it is able to reach cracks and crevices that might be missed by something like fiberglass. It tends to be highly affordable, is environmentally friendly as is most spray foam, and can be installed without a professional.
    • However, there are many cons to cellulose as well. Cellulose insulation is not suited for sloped attics, because it is among the heaviest types of insulation. It is not considered airtight, meaning loose air can still escape and it had a tendency to absorb water, so keeping it dry is especially important.

What are the best types of installation for attics?


 In most cases, the best type of installation for attics is spray foam. Spray foam, unlike the other options, is airtight, water-resistant, fire-resistant, and resistant against pests. In addition, by nature of its application, this type of insulation is able to fill crevices and cracks. While it does require a professional and while it is more expensive initially, you may save in the long term by cutting back on bills and even possibly having to replace it less often.

Are there any pitfalls to foam installation for attics? No installation is perfect, and if you’re looking for the best installation possible, you need to be aware that even foam installation can be done improperly. Here are some things to be on the lookout for:

  • The material. Not all spray foam is created equal, and some brands simple market as “spray foam insulation’ so it’s important you work with a professional and are aware of what will be used. Without proper materials, the benefits of spray foam, such as moisture and mildew resistance, may be negated. The best spray foam should:
    • Be made of polyurethane
    • Have a closed cell form, with anti-mold agents
    • Adhere to building codes
    • Dry quickly
    • Expand to fill in gaps and crevices
  • Bad odor. One of the biggest downsides to foam insulation for attics is that they can have an odor. But if done properly, that odor should fade reasonably quickly. Large units called air exchange units should be used during installation to prevent these odors from staying too long.
  • Not sprayed thickly enough. Spray foam must be spray in a thick enough layer and typically three inches away. Make sure you understand how and where it is being applied and that the contractor provides sufficient details.
  • Improperly mixed chemicals. If the chemicals in a spray foam are not properly prepared by you or a professional, the insulation can peel away. It should be applied with high-pressure installation, and if you go with a professional, ask for a warranty against any peeling.
  • Overall poor installation can lead to a number of problems, which is why the best attic insulation is done by a professional or someone with experience working with this type of insulation.

What are the best foam installation kits for attics?

While we do recommend getting professional guidance, we’ll take a look at some of the best foam insulation kits available, keeping in mind the criteria and all the pros and cons we have discussed so far. Just keep in mind that you’ll save more money in the long run at least having a consultant than if you do not know how to install it yourself properly.

  1. Dow Froth-Pak Spray Foam Insulation Kit:  This kit contains closed-cell foam and comes with a fifteen-foot hose, with a tank of isocyanate and a tank of polyol. The kit comes with eight spray nozzles and six cone nozzles for ultimate versatility and cures and settles in under a minute of spraying. You’ll get up to six hundred and twenty board feet of foam, and it also is suited for wall piping support.
My Top Pick: Dow Froth Pak 650, Spray Foam Insulation Kit
Spray foam is water-resistant, pest-resistant and honestly, it's best type of installation for attics. Our top recommended product is the Dow Froth Pak 650, Spray Foam Insulation Kit - it comes with plenty of foam and nozzle versatility.
Check Price
We earn a commission if you click this link and make a purchase at no additional cost to you.

2. Foam it Green 602 Closed Cell Spray Insulation Kit: This is yet another closed-cell insulation kit that is popular for easy, one application use. You’ll get around six hundred board feet of foam with one-inch thickness and includes fire-retardant properties. The steel canisters are pressured with nitrogen.

Foam It Green 602 Closed Cell Spray Foam Insulation Kit
Check Price
We earn a commission if you click this link and make a purchase at no additional cost to you.

In addition to the foam itself, you must protect yourself. We suggest a pair of anti-fog safety glasses like Dewalt Concealer Dual Mold Safety Goggles. These have protection against scratches, dust, and debris to keep your eyes protected, plus clear lens and anti-fogging technology.

Finally, to protect your entire body, consider a protective suit, like DuPont Disposable Elastic Wrist, Bootie, and Hood. This suit covers head to toe to protect against particles and even includes a zipper enclosure with boots.

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