Tiny House

Tiny House Insulation: The What’s You Need to Know

By taufiqhaque

The tiny house has gained popularity as a good housing option within a pretty short time. The concept is relatively new, but factors like environmental sustainability, less use of space, and the freedom of moving around drew people to this; not to mention the cost of building and owning a tiny house is significantly less than regular housing.  Read more about tiny house insulation ideas and ADU insulation for winter below.

The tiny house has become a more suitable option for temporary and even permanent housing for a lot of people. Other than housing, tiny houses serve as a good option for any dedicated small space like home offices. These kinds of permanent tiny houses (that are usually built in the backyard) are called ADUs, and ADU insulation for winter is just as important as insulating your permanent tiny house. 

Whether your tiny house is used for living or other purposes like an office, insulation is an important factor you must consider while building your small home. Insulation is what keeps your little home warm during winter days and if you choose the right material, it will also help your house stay cool during warmer days. Insulation is something you’ll have to put a lot of thought behind because the wrong choice or setting will do you more harm than good. So if you want to prepare your ADU and want the important stuff about ADU insulation for winter; or if you want to know more about tiny house insulation, you’ve come to the right place. Here’s our guide about ADU insulation for winter and tiny house insulation to help you along.

What Is Tiny House Insulation?

Tiny House Insulation: The What’s You Need to Know

Insulation for your tiny house or ADU insulation for winter is laying a protective layer on your walls and ceilings to seal the air gaps/leaks and keep your house warm in the cold. Insulation creates a barrier between your wall and the outside so the heat transfer between the inside of your tiny house and the outside environment (that has a lower temperature) slows down significantly. Some insulation materials can also make your house more soundproof, but most of them are geared towards heat protection.

In simple words, insulation is using layers of protective material on your walls and other surfaces to keep the heat transfer rate between your home and the cold weather lower and to keep your tiny house warm during winter. Insulation materials also help in keeping your house more chilly because, during warmer days, the outside heat will take more time to get in.

ADU Insulation For Winter: What Parts Should You Consider For Tiny House Insulation

You’re probably thinking that insulating your walls with the thickest insulation material will do the job and you can go back to sleep with a toasty winter in your mind. Unfortunately, that is not the case. Insulating your walls only won’t do much of a heat-trapping job because there will be other outlets where the cold will seep through, so you will have to make sure you have all possible air leakage pockets sealed during your tiny house insulation process.

This goes without saying but the first thing you should be insulating is your wall. Walls work as the biggest conductor for both heat and cold so insulating them will rid you of the biggest disadvantage. Walls will also take the longest time for installing insulation material so do your walls and start thinking about them earlier.

The next thing you will have to insulate is your roof. This is another given, we know, but insulating your roof takes equal importance to insulating your walls. Your roof is a bigger conductor for cold, which is why it is recommended to use insulators with higher R values for your roof.

Insulating your floor is another major point, especially if you’re working to get your ADU insulation for winter. Since your floor stays close to the ground (or metals of the wheel if you have a moving tiny house) and can be made with concrete, it will work as a thermal bridge and suck the heat out of your tiny home. 

These are the major points you must insulate but depending on the area you live in and the air leakage passages, you might have to insulate your windows and the skirts of your walls too.

Tiny House Insulation: What Materials You Should Use In Your ADU Insulation For Winter?

Picking the ultimate insulation material is completely up to you because it will vary based on your living area and available space, but here is a list of insulation materials to make the job of picking easier.

Before moving on to that, let’s get a basic question out of the way.

What Is The R Value?

R-value is the measurement metric that indicates how well your insulation material will stop the heat from transferring.

Your insulation is a barrier that slows down the heat transfer process between colder places (think the outside) and warmer places (like your tiny home) since it is impossible to completely stop the heat transferring process.

For R values, a higher number will mean a slower heat transfer, or simply speaking, a higher number will mean more warmth inside your house. Always remember to compare the R-value per inch for comparison and not the whole value, that way your comparison will be more equal and you’ll have more chances to pick the perfect insulation material.

Insulation Materials For Your Tiny House

1. Closed-Cell Foam Spray

Tiny House Insulation: The What’s You Need to Know

R-value per inch: 6.0

Costing per square foot: $0.70 – $1.73

Sustainability: Not eco-friendly

Installation skill level: Professional

Closed-cell foam sprays are an interesting option for insulating. You’ll need professional help for installing, but the fact that foam spray has the highest R-value makes up for that full well.

Closed-cell foam sprays are made of an expandable material. For installing this, the professional crew will spray this foam over your walls and roofs. The foam will then expand and seal off all possible air leakage and pockets that can pass air through them.

Foam sprays cost more than other options including the installation charge, but it is worth it. Closed-cell foam sprays are easy to use and have the most chance of sealing everything properly. It can also reach tough spaces inside your home (like your corners) so you can rest easy knowing there won’t be air pockets hiding anywhere. It is also easy to cut so if you think the thickness is too much in some places, you can cut them off as much as you want. It works as a vapor barrier by itself and is a built-in air sealer too.

2. Rock Wool

Tiny House Insulation: The What’s You Need to Know

R-value per inch: 3.3

Costing per square foot: $0.62 – $1.50

Sustainability: Eco-friendly

Installation skill level: Low

Rock wool is a close second to closed cell foam spray as an insulator. It is rigid, easy to install (you can even do it completely by yourself), and travel-friendly.

Rock wool is made of rocks and industrial waste. As you can already see, this will leave less ecological footprint than other options.

A huge plus point of rock wool is that it is water-resistant. Even if the water gets to your insulation’s cavity, rock wool will keep its rigid structure and won’t deflate on contact with water. This means rock wool can be a long-lasting option as there won’t be many cold spots because of deflation. It also handles moisture better than other options so you won’t have to worry much about molds.

Another plus point of rock wool is that it is fire-resistant. Rock wool also does a good job of toning down sounds which means it acts like a “soundproof” layer, making it a good option to use around personal spaces. Rock wool is travel friendly so you can use rock wool to insulate your tiny home on wheels too!

3. Fiberglass Batt

Tiny House Insulation: The What’s You Need to Know

R-value per inch: 3.1

Costing per square foot: $0.64 – $1.19

Sustainability: Eco-friendly

Installation skill level: Medium

Fiberglass batts are the most commonly available option for tiny house insulation. Sure, it doesn’t have the highest R-value per inch but the availability has made it cheaper.

Fiberglass is made from sand and recycled glass. The material is durable but it isn’t fire resistant and can be a little tricky to install.

Fiberglass batts come in two types, one with a vapor barrier and the other without it. So you can get one with a vapor barrier facility for your ADU insulation for winter even though there won’t be air sealing like foam sprays. Fiberglass is easy to get and is cheaper than other options on this list, doesn’t necessarily need professional help to be installed and you can also bump up the R-value by installing an outer layer of insulation.

Other than being the most common option, another major pro of fiberglass is that it comes as almost ready to install. The batts are pre-cut as 3.5 inches (for your 2×4 walls) or 5.5 inches (for your 2×6 wall) sizes already so you won’t have to worry about cutting things. You will just have to unroll it, cut the height you want, and then staple it to your wall cavity.

For all the pros, the most notable disadvantage of fiberglass batts is that it doesn’t travel friendly so if your tiny house stays on the run, you’ll have to scratch this option off your list.

4. Foam Boards

R-value per inch: 3.8-5

Costing per square foot: $0.75 – $1.45

Sustainability: Not eco-friendly

Installation skill level: Medium

Foam boards are some widely used options for insulation. They come in many forms and one of them is EPS.

EPS is very common as an insulation material and has a 3.8 R-value. It is durable, it lasts for many years which makes it the second long-term option after rock wool and it is more breathable than other foam boards. It deals with water pretty well for its price and handles moisture better than other foam boards. EPS is easy to install and is less likely to be attacked by bugs.

The main selling point of EPS is that it is cheaper than many options and can handle water well, so it is mostly used in places where contact with water is almost sure.

The second foam board we will talk about is XPS. XPS starts as crystals of foam and is then melted to get its foam form. It is good in resisting moisture so less chance of molding, but it has trouble passing water through it. It absorbs water slowly and releases it equally slowly so it is better not to use this around water.

5. Denim-Cotton

R-value per inch: 3.5

Costing per square foot: $0.76 – $1.41

Sustainability: Eco-friendly

Installation skill level: Professional

Denim is one of the most environment-friendly options for insulating. It is made from recycled denim and is an option that will leave less ecological footprint than other ones on this list.

Denim is very good at absorbing moisture, and you can easily get this in your area because of how common it is. Unfortunately, it can be very difficult to install because of how heavy it is, and this not being available in pre-made suitable sizes doesn’t help either. The edges of denim insulators can also fold while installing, and the heaviness makes them unfit for moving tiny houses.

Things you should consider before deciding

Before you decide on your insulation material, there are some things you’ll have to consider.

Your ideal insulation material will depend on the area you live in. picking insulation material for colder areas is easy, but if you live in a warmer area, it can be difficult for you because you’ll have to be extra careful about moisture build-up.

Look for insulation guidelines of your area to know what is the minimum R-value you should use to insulate your tiny house. The R-value for your wall insulating material will be lower than your roof insulating material so take a closer look at that.

Make sure the insulation material you want to use is available in your area. Your insulation material will also depend on cost, ease of installation, and how long it can provide good service.

Consider putting extra insulation around the thermal bridges (especially if your tiny house is an RV/moves around a lot). The metal around your wheel is a major thermal bridge and not paying attention might break your whole insulation plan.


And this ends our guide to tiny house insulation. For us, the best choice is the closed-cell spray foam but if you’re on the move, rock wool can be a good option for you. If you’re looking for a cheaper option for your ADU insulation for winter, fiberglass is the way to go. Make sure to follow manufacturer guidelines if you’re installing the insulators yourself and if you have any more questions feel free to let us know!

You can also read: Tiny House Window Ideas in 2022


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