The Essential Guide to Insulating a Tiny House

The Essential Guide to Insulating a Tiny House

All About Tiny Houses is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.

tiny house insulation

Insulating a tiny house is an important step to make your life more comfortable in your mobile home. It’s what keeps your dwelling warm during the winter and cool in the summer. Furthermore, it also contributes significantly to making your home energy efficient in its use of heaters and air conditioning. 

Insulating your tiny house is a must, especially if you want to live in a comfortable home. The great news is that with little to no experience, you can insulate your residence. There are also plenty of materials to choose from, which can affect the project’s cost and difficulty.

If you don’t want the heavy lifting, you can easily hire a professional home insulation contractor. Some of the materials used in insulation may not be beginner-friendly or require careful handling to ensure it’s appropriately installed. In which case, it’s better to leave it to the pros. 

Consequently, if you buy a tiny home unit from a manufacturer, they usually have pre-installed insulation. Meanwhile, tiny home builders can also place the installation material of your choice while they are constructing your unit.

In this guide, we will discuss everything to know about insulating a tiny house. We have also included different insulation options, their cost, and some recommendations. 

How Much Does Insulating a Tiny House Cost?

Insulating your tiny home can cost anywhere between $0.35 to $2 per board foot. Different components affect the price, but the most significant factor is the material used. 

Depending on the type of insulation you decided on, this project could be as affordable as $1,200 or upwards of $2,500. Generally, the larger your tiny home is, the more expensive the insulation. However, small houses are much smaller than traditional housing options and are much cheaper to insulate.  

Later, we will also discuss the average cost of each material to help you better in weighing your options.  

insulating a tiny house

What is the R-Value in Insulation?

You may have noticed that different materials have varying R-values. For example, polyurethane styrofoam has an insulation rating of 5.6 to 8.0. But what does this figure mean?

R-Value is a rating that measures the ability of a material to block off heat. The higher its value, the more insulative the material. 

Different parts of the house usually require different R-values to ensure they could trap heat efficiently. A traditional home’s attic must have R-38 insulation according to the Energy Conservation Code

R-values can also vary depending on the thickness of the material. As such, fiberglass with a depth of 3.5 inches has an R-value of 10.9. But, once its thickness increases to 6 inches, the R-value also jumps to 18.8. 

Different Types of Materials for Insulating a Tiny House

1. Fiberglass

Fiberglass is one of the most reliable materials you can use for insulation. This material is a combination of reinforced plastic material and glass, which makes it quite sturdy and durable. However, installing fiberglass is challenging since they may irritate once it comes in contact with your skin.   

In terms of insulation, it’s R-value is from 2.9 to 3.8 per square inch for the batts type and 2.2 to 2.9 per square inch for the loose type. The batts type has an estimated cost of $0.64 to $1.19 per board foot. If you have a professional install it for you, it will cost you an additional $100 to $300. 

Installing fiberglass is also much easier than other synthetic materials. You need to fit the large roll batts in between the studs. Moreover, the installation only requires a few pieces of equipment such as utility knife, putty cutter, and tape measure.   

Furthermore, it tends to sag over the years, which may cut down its effectiveness in containing heat. 

Fiberglass insulation
Photo by Penumbra via Flickr

Pros

  • One of the most inexpensive insulation materials in the market
  • Some brands are covered in plastic which acts as moisture barriers
  • This material does not burn 
  • Consistent insulation that quickly surrounds everything inside the walls 

Cons

  • Doesn’t cover the walls from cold entirely because it’s not thick enough
  • Settles and sags over time which cuts down its insulation efficiency
  • Loses its R-value once it gets wet or moisture gets into it
  • Contains potentially toxic chemicals such formaldehyde

2. Cellulose

Cellulose is one of the most preferred insulating materials because of its low impact on the environment. It’s made of recycled materials, mainly newspaper shredded fibers that make 80-percent of the material. 

It’s also mixed with boric acid to give it fire-resistant properties. Loose-fill cellulose has an R-value of 3.5 per square inch of thickness. A bag of cellulose has a price tag of $11.50 to $12, which translates to roughly $0.85 per board foot. 

Installing dense-pack cellulose requires drilling into the walls or floor about 2-inches or more in diameter. After this, the nozzle application will be inserted in it to inject the insulating material.

On the other hand, wet cellulose follows the same process. However, water and binder compounds are added into the mix so that it will stick with other building components. The method simultaneously insulates, and air seals the walls or floor. 

Pros

  • When treated with boric acid, it can become fire and pest resistant
  • A bit cheaper than fiberglass
  • Lower health risks than other potentially toxic materials in this list
  • Can help reduce discarded cardboard and paper products

Cons

  • Installation cost is a bit higher than fiberglass
  • When installing it leaves a vast amount of dust; hence, a breathing mask is required
  • Both wet and dry cellulose need vapor barriers
  • Quickly absorbs moisture which can expose it to molds and decay

3. Blue Jeans or Denim

If you have tons of denim or blue jeans at home, you can also use them to insulate your tiny house. You can also use other recycled textile fibers and form them into batts. The remarkable thing about using denim is that they don’t contain any chemical irritants. 

Ultratouch is one of the most popular brands of denim insulation in the market. A 16” x 48” multi-purpose denim roll only costs $6 per roll. In terms of insulation efficiency, it has an R-value of 3.5 per square inch. 

Installing blue jeans is also much easier than other materials in this list because it doesn’t contain any harmful chemicals or irritants. Before installing it over a wall panel, make sure the denim roll is fully rebounded. Furthermore, you want the denim sheet to be at least 0.5 inches thicker than the wall gaps to ensure a snug fit. 

Moreover, blue jeans are a renewable insulator that doesn’t contain formaldehyde or any itchy fibers. However, denim insulation costs almost twice as much as fiberglass. You also need to apply vapor barriers, which also requires a hefty sum. 

insulating a tiny home

Pros

  • Doesn’t contain formaldehyde or any other toxic substances
  • Can easily be DIYed which can save you money from hiring a contractor
  • Denim lasts for a long time
  • Becomes fire and pest resistant when treated with boric acid

Cons

  • Costs almost twice as fiberglass insulation
  • Requires a vapor barrier to be effective
  • Batts may not bounce back from their original shape after shipping
  • A bit difficult to cut

4. Cell Spray Foam

If you are looking for the most effective insulation material, then look no further than a closed-cell spray foam (CCSF). CCSF has an R-value of 6 to 7 per square inch, which is almost double that of other materials on the list. On average, it costs around $0.90 to $1.25 per board foot. 

You can also opt for a cheaper but less effective open-cell spray foam (OCSF), which has an R-value of 3 to 4per square inch. Installing this type of insulation takes you back $0.25 to $0.50 per board foot. 

Closed cells are pressed together so that moisture and air won’t get into the foam. Because of this arrangement, OCSF is more rigid and stable than its closed counterpart. On the other hand, open-cell spray foam is not fully encapsulated and are deliberately left open. 

Consequently, cell spray products are usually packaged with ready kits that include hoses, nozzles, and tanks with foams. These inclusions can increase the price of cell spray foam products.

Pros

  • Provides an airtight seal for complete insulation
  • Impermeable to water which extends its life span
  • Can add strength to your roof and walls
  • Does not lose its R-value over time

Cons 

  • Requires protective equipment during installation
  • Needs to be applied at the right portion and temperature to prevent outgassing
  • Contains potentially toxic substances when used incorrectly

5. Foam Board

Foam board is another material you can use to insulate your tiny home. It’s made of polyurethane polystyrene and polyisocyanurate. These rigid panels provide not only excellent thermal resistance but also add structural strength to your small house.

Foam boards are good for insulating any part of your home. It has an R-value that ranges from 3.8 to 4.4 every inch of thickness. This insulation material is often sold in 4×8 foot sheets. On average, installing foam boards cost $0.67 per board foot.

There are two types of foam boards, namely: extruded expanded polystyrene (XEPS), 

molded expanded polystyrene (MEPS). The more expensive XEPS is denser, has higher comprehensive strength, and better resistance to moisture absorption. Meanwhile, MEPS is cheaper and is often used in structural insulated panels and insulating concrete forms.

Foam boards are also sold in various thicknesses and can be trimmed down to fit the floor and wall cavities. The unique property of foam also allows them to be DIY-friendly since they are relatively easy to install. However, the main challenge with foam boards is cutting them into smaller pieces so that they fit perfectly.  

insulating a small home
Photo by ann-dabney via Flickr

Pros

  • Offers high R-value even without a foil facing 
  • Expanded polystyrene board doesn’t have Hydrofluorocarbons which is good for the environment
  • XPS is very resistant to moisture and can be used underground
  • Polyiso board has numerous facing options like plastic and aluminum

Cons

  • Joints between boards and sheets need to be taped together which prolongs the installation 
  • EPS contain air bubbles which may stop heat transfer
  • Rigid foam is susceptible to UV ray damage when exposed directly to the sun

6. Sheep Wool

If you are looking for a sustainable insulation material, then you should consider sheep wool. Clothes made of sheep wool are excellent in regulating heat and absorbing humidity. If you ever had woolen jumpers, it’s made of sheep wool.

In terms of insulation efficiency, sheep wool has an R-value of 3.6 per square inch for wool batts and 4.3 per square inch for blow-ins. However, while sheep wool offers a lot of benefits, you have to pay a premium of $0.67 per board foot. 

Regardless, sheep wool offers better thermal conductivity than many of the other materials on the list. Sheep wool has a thermal conductivity that ranges between 0.035 – 0.04 Watts per meter times Kelvin (W/mK) compared to other mineral wool, which is at 0.044 W/mK. 

Wool fiber also has a crimped nature, thanks to millions of tiny air pockets that create a thermal barrier that effectively traps air. Furthermore, wool absorbs harmful substances like formaldehyde, sulfur dioxide, and nitrogen dioxide. It then neutralizes these substances through a process called Chemisorption. 

Pros

  • Environment-friendly and has a minimal carbon footprint
  • Excellent at absorbing moisture and has an excellent thermal conductivity
  • Non-flammable and can last for a long time when treated with boric acid
  • Material is flexible and fills gaps easily

Cons

  • Borax is potentially toxic
  • Quite a bit expensive; especially on its installation cost
  • Sheep wool is also treated in harsh chemicals to remove scab mites

7. Cotton

While very few use cotton to insulate their homes, it’s still pretty viable. Cotton is a non-toxic material and can easily fit even the thinnest walls. Furthermore, it has a less negative impact than most of the items on this list.

In terms of R-value, cotton averages around 3.5 per square inch. However, because they are much thinner than say fiberglass, you need to stack more sheets to get the same insulation efficiency. The average cost of cotton insulation is around $0.95 per board feet. 

Another reason you may want to consider cotton is its ability to block sounds. Furthermore, it’s safe to handle and does not cause any irritation. However, there are a couple of issues that you should also consider before installing cotton.

First, cutting cotton is not an easy task, and you need to use a very sharp knife to get it done. Second, cotton is a bit heavier than other materials on this list. Hence, if you are quite particular with the weight of your tiny home, this insulation material might not be for you. 

Photo by CaraGreen via Flickr

Pros

  • Cotton is safe to handle and easy to install
  • Doesn’t have any toxic or harmful substance
  • Effectively blocks sounds 

Cons

  • Lower R-value compared to other materials on the list
  • Cotton is a bit heavy which can be an issue for tiny homes on wheels
  • It’s hard to cut into the right sizes

8. Hemp   

One of the insulation materials that holds much promise, hemp is a great sustainable alternative. It’s non-toxic, renewable, and quite sturdy, which under the right conditions can last a lifetime. Furthermore, it has moisture control properties that help regulate the right temperature for your tiny home.

In terms of insulation efficiency, it has an R-3.5 per square inch rating. However, because they are quite rare in the US, you may need to spend a much higher sum to install them. On average, installing hemp into your tiny house will set you back $1.90 per square foot.

Despite its hefty price tag, hemp might be worth it mainly because of its resistant to pests and insects. Additionally, they also reduce sound transmission and can absorb moisture from your home’s framing materials.

However, aside from being twice as expensive as fiberglass, hemp is also hard to cut down. As such, you may need a power saw if its in a DIY project. Hemp also doesn’t compress well, which can increase your shipping fee by a bit. 

Pros

  • Hypoallergenic and natural which makes it safe to install even without special equipment
  • Quite sturdy and has a longer lifespan than most materials in the list
  • Safely absorbs moisture especially from framing materials
  • Reduces sound transmission

Cons

  • More expensive than most popular insulation materials
  • Tough to cut and requires a saw to do the job
  • Takes more volume when it’s shipped because it doesn’t compress well
how to insulate a tiny home
Photo by Nicolás Boullosa via Flickr

Conclusion

Insulating a tiny home is a must, especially if you want to live comfortably during the winter months. Fortunately, there are tons of materials you can choose from to match your budget and preference. 

Related Questions

Is it easy to install insulation in a tiny home?

Some materials are easy to install and doesn’t even require professional help. However, some substances require proper handling or treatment. As an example, fiberglass may irritate when it touches your skin. 

How long do insulations usually last?

Most insulations can last a lifetime, especially if they are correctly installed and are not exposed to any damage.

All About Tiny Houses is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.

Leave a Reply

Your email address will not be published. Required fields are marked *