Thermal insulation for a prefab house should be a top priority as if picked correctly could make the living environment much healthier and sustainable. However, finding out what is the best insulation to use in a prefab house could be a hard task as it involves many different factors.
For that reason, I’m going to help you understand how you could find out what is the best insulation for your new prefab house.
The best insulation to use in a prefab house will be a material that can perform best according to the local climate, typical use of the house, building method, and the building budget. Answering those factors will determine what will be the best thermal insulation for each user.
With that said there are a couple of things one must understand before choosing insulation material for a prefab house, which will help make a knowledgeable decision. Those things are the basics of thermal insulation, the different types of materials, each type’s performance, how eco friendly it is, and how good it will perform into the future.
In other words, this post will explore prefab house thermal insulation options for your benefit, so once it is time to pick which material is best for your prefab home you will have the knowledge to make the right decision.
With that out of the way let’s get into understanding insulation materials.
Thermal Insulation General Information
Thermal insulation needs to be able to limit the amount of heat transfer and/or loss both from the outside to the inside of the prefab home and from the inside to the outside.
In other words, the insulation is used to make our living spaces more comfortable than the outside. By limiting the heat running off the house during winter, and the cool AC air during the summer.
If the insulation is properly installed and chosen right for the house’s environment the costs of heating and cooling would be much lower than without insulation or bad insulation.
Meaning, thermal insulation isn’t only improving our living environment it is also helping us become more sustainable as electricity and other fuels are used less and less as the insulation and air toughness are improving.
Additionally, insulation makes our home’s indoor environment much healthier, as vapor and temperature difference can cause mold which can cause breathing health issues and low life quality.
So let’s understand what thermal insulation actually does by understanding the physical mechanism behind heat transfer.
What Is Heat Transfer
Heat transfers in 3 ways as physics teaches us, the first conduction happens when two materials touch each other and there is a temperature difference between them, as a result, heat will transfer from one to another.
The second is convection, this form of heat transfer happens through a gas or liquid medium that is exposed to temperature differences which creates motion in the medium that moves and transfers the heat throughout the area.
The third is radiation, this is how we get the warmth of the sun, and this is what you will feel when sitting beside the fireplace – waves of heat.
No matter what the heat source is, the same three mechanisms apply, sometimes you won’t feel them all but they are working and are present to a certain extent.
What Types of Thermal Insulation Are There
Now that we understand how heat transfers in the environment the next step is to learn what are the main thermal insulation materials available for insulating a prefab house. The differences between the materials are sometimes huge, from an environmental, budget, and performance point of view.
Thing is that one should consider all those factors when choosing certain materials for home insulation. The best insulation will be the one that best suits the owner’s full decision matrix.
Mineral Thermal Insulation
The first type is the mineral thermal insulation materials, such as rock, stone, and glass wool. These are industrialized materials created from sand, glass, and volcanic rocks that transform into wool-like fibers and combined into boards and other types of products.
Mineral wool insulations are best to use in a prefab house if the house will be located in a dry climate area, and the value will be high compared to a pair price.
Mineral wools for the most part are not eco-friendly as their production process is highly pollutant to the environment, even when the raw material is of recycled source the process of turning it into fibers is still polluting, with high levels of CO2.
The mineral type insulation materials are inherently fire resistant, could have a high-density product, and are very low-cost materials. Additionally, those materials have great R values (will talk about it soon), however, are exposed to degradation in performance if not sealed against air properly.
Mineral wools are approved to use all around the globe even though while installing those materials it is recommended to use protective gear such as masks, gloves, long sleeves, and glasses to prevent any irritation to the skin, eyes, and breathing system.
Lastly, the mineral wools are approved to be used in building codes with minor adaptations to thickness, density, installation, and whether or not the material should be covered.
Synthetic Thermal Insulation
The second type of thermal insulation is synthetic insulation created from crude oils, among them are two of the most famous and used insulation materials – polyurethane foam, and polystyrene foam. Both materials have a very high R-value and will be very efficient insulating houses, however, not without some troubling cons.
Synthetic thermal insulation is best to use in a prefab house if the budget is tight, this will be a great option to get a high insulation value for a fairly cheap price.
To begin with, synthetic thermal insulation materials are not eco-friendly as they are produced from fossil fuels. Some of the pros of having a prefab house are being more sustainable and eco-friendly, using this type of insulation is kind of missing the point in the first place.
Moreover, the production process of synthetic insulation is polluting on its own and added to all that is the fact that those materials are not recyclable.
The good thing though about these materials are that their thermal insulation performance is higher than most if not all other materials.
Aside from that, they are less susceptible to water damage and as such could put less worry regarding the vapor barrier during their installation process. As these materials are practically “sealed” air can’t flow through the materials which makes them insulate better than the wools above. (no/less convection)
Additionally, those materials have a very low cost and could be a great fit for those that look for a high value insulation performance yet low cost.
Regarding synthetic’s fire performance, they are practically zero, those materials are not by any means fire resistant and burn fast and hot. So regarding fire safety, consider adding a fire retardant treatment when using those materials.
Bio-Sourced Thermal Insulation
The third type of materials that hold the largest variety of sources is the bio-sourced insulations. In a nutshell, those are insulation that comes from nature both animals and plants and don’t go through a lot of industrialization, though some are a by-product of other industries.
Examples of some bio-sourced materials are sheep’s wool, hemp, cotton wool, wood wool, straw, feathers, recycled newspaper, cork, and more are added every year. This type of insulation will be best to use in a prefab house if the environmental issue is of higher importance to the owner.
The biggest advantage of all those materials is the fact that they are eco-friendly, either due to the fact they help with recycling by-products that would have been sent to the landfill or by utilizing natural resources to our advantage instead of producing new materials with high environmental impact.
These materials have very low production pollution on the environment, they could be recycled in the future, and are renewable. When it comes to being very ecological the bio-sourced materials certainly win the jackpot.
However, there are some downsides to them just like any other thing in life. First, their cost is high and sometimes too high in comparison to the other less ecological options, this is due to the fact that most of them are produced in small quantities and as such makes it a big investment that generates low yield at the end.
Second, they are not fire-resistant for the most part and do need to get through a fire detergent process to be able to serve safely. This issue must be taken care of as in many places this is obligated by law, so be mindful of the fire resistance issue as if missing could prevent you from getting insurance for your house.
Third, some of those materials are pests susceptible, for example, any wood based material could suffer a termite invasion. However, this could be handled by simple treatments to the wood and by sealing the insulation materials properly.
The last thing to be aware of is that some of those materials when not installed properly will not insulate as required. This could happen if the density is not sufficient, or there are too many air gaps inside the wall and other element cavities, the insulation performance is highly affected by air and water vapor.
For that reason, some factories that do work with bio-sourced insulations have machines and computers that put the right amount of material to create the proper density for best performance. Those companies understand that minor changes in the insulation materials could change the house’s ability to keep its temperatures and would lose a lot of electricity in the process.
Bio-sourced insulation is great for the environment for the most part, but not all are right for every home. There are still some improvements to be made with those materials, however, they are a great step on track for our housing market to be more environmentally friendly and less polluting and destructive.
Cellular Thermal Insulation
The fourth type of materials is a mix of the others but a whole new category, it is the cellular (not cellulose) Insulation. A great example is a cellular glass, a closed-cell glass foam. And in my eyes, the Best insulation to use in a prefab house on every occasion.
This material has a very high R-value, with great water and fire resistance, high density, great properties for the building industry, eco-friendly, recycled and recyclable, versatile in use, and very durable.
Cellular insulation materials are not that new and have been used in factories and other industries for years, but in recent years with production improvements, these materials have become more valuable to use in the general housing market.
It has a low environmental impact with very low air and waste pollution during its production, must of those materials are produced from recycled materials, the waste from the production process goes into other products (such as breeks), and the air pollution is just nothing to compare with other insulation materials (apart from the bio-sourced insulation).
In most cases, these insulation materials are fire-resistant at the highest degree, and water and vapor resistant as well. Those treats make them very attractive as it means that those materials are highly durable.
Some of the cellular materials could work in combination with other systems, for example, the cellular glass could work with the waterproofing system by spreading hot bitumen on top of it to create a sealed and insulated system.
The only thing to know is that those materials of higher quality do cost more than the mineral and synthetic insulations. But make no mistake, the durability, ease of installation, and performance are worth the extra costs.
What is R-value
The R-value, I have mentioned above when I talked about the different types of insulation you might encounter. But, did not have the chance of explaining what this actually means.
So, R-value, known as the Thermal Resistance of any insulation is determined by 2 things, first, the thickness of the material, which could be changed according to needs. Second, the Lamda value, which is unique to each material and density of it. The lamda is in other words the Thermal Conductivity of the material, meaning how good or bad is the material conducting heat from one side to the other.
Now in order to calculate the R-value, Thermal Resistance of any material take the thickness in meters (7cm equals 0.07m) and divide it by the Lamda value of the material. Say rock wool’s lamda is 0.033, the R will be equals to 0.07 divided by 0.033 equals – 2.12.
So in order to get a high R-value without changing thickness one must find a material with a lower Lamda-value.
How To Pick The Best Insulation To Use In A Prefab House
Now that the basics of thermal insulation are covered, let’s understand how one should approach the decision of picking the best insulation for prefab houses.
To begin with, not all prefab home manufacturers will have all insulation options available and some will not have any at all. However, understanding the different insulation material available might make the decision clearer as to which one is better for your home.
Choosing the right insulation is all about narrowing the available field into a small number of options that will fill as many boxes on your list as possible.
The factors that will help make the decision are:
- The location of the house
- A minimum R-value
- Construction laws
- Eco-friendly material
- Sustainability
- Costs
The Location Of The Prefab House
Where a new house will be standing has a lot of influence as what type of building method will be preferred and what will be the best materials for the house.
With that said, the influence of the surrounding environment on the house and the performance of the thermal insulation is huge. This is why it is super important to understand what the conditions will be all year long.
For example, a house that is to be located on the coastline near the ocean will have a lot of sun exposure during the summer months and very high humidity to handle. As on the other side of things, a house at a higher altitude in the middle of the forest will have less sun exposure and moderate to low levels of humidity, depending on the hour of the day.
Both those houses will have thermal insulation, however, each will need either a different material or higher thickness, which will be determined by the application method as well.
Every area in the world has some sort of data in regards to what type of climate it has, with this data you could make sense as to what would be good insulation for that specific area.
Say an area has lots of high humidity days, it is worth investing in high-quality closed-cell material, that will limit the ability of water vapor to penetrate the material and lower its insulation ability over time.
There are many other nuances to be dealt with during the selection process and understanding what the materials will need to co-op with will make the picture clearer.
Minimum R-values For The Best Prefab House Insulation
Once one understands what the local climate is like a basic minimum R-value should be established so the elimination process could start.
As mentioned above the local environment will determine most of what the insulation should be able to withstand, with that, setting a low limit for R-value performance is a must.
This will help divide the materials by their abilities to perform and their thickness, the thickness has a lot of significance as it impacts other materials such as wood and steel beams for the frame of the house.
Additionally, having a range of R-values will help later compare the materials both in thickness and additional costs compared with performance.
Best Insulation Must Stand Local Construction Laws
Many countries these days, especially in large metropolitans set rules regarding how and what houses should be built like. This includes what materials are allowed to be used and what is not allowed, and what should be a basic limit for insulation materials.
As countries wish to make sure that homes are being built safely, they also wish to limit the costs of energy and pollution effects by setting the right mandatory limits for certain methods and materials.
One of the most important limits is the insulation ability of a house, there are certain roles to each state and sometimes city. Make sure to check that your prefab house will comply with the local building code, this could be done through your chosen manufacturer or your inspector and contractor, but do not forget that for getting the living approval you must meet the minimum requirements set by your local authorities.
Eco-Friendliness Of The Best Insulation Materials
This is in my eyes the most important factor to check, as for many choosing these days to go with a prefab house means being more concerned about the environment and wishing to live in a more sustainable prefab house.
With that said, choosing a very good insulation material that puts a lot of pollution during its production process is counterproductive to the desire to be more eco-friendly.
Insulation materials could be checked for their environmental impact easily, first, raw material origin, second, production pollution, third, recyclability, fourth, durability.
Raw materials for the most eco-friendly insulation will either be from a renewable source such as plants or animals, or from another industry to be recycled into insulation material.
Production process of many insulation materials involves high demand for energy, this could be managed by switching the energy sources of the factory to more renewables and sustainable sources. If you go to the insulation manufacturers’ websites you will see if they are sustainable, it will be posted all over their front page.
Additionally, there is the direct pollution of the environment during the production process, again this could be managed by technology to reduce air pollution and by using the waste to create other materials. Be sure to ask what each factory is doing to help reduce the effects of their production.
Recycling, not a dirty word anymore, however is important to understand whether or not the insulation materials can be used again to reduce waste pollution. There are many insulation materials that can be used to create other products or be used again after a short refurbishment.
Durability of the insulation materials will determine whether or not a prefab house would need to go through renovation just to change the insulation that is no longer functioning. This could happen as R-values are only representing the ability to “block” conduction, while convection could very much still transfer heat, energy, and water vapor, which all with time degrade the insulation material performance.
Demanding to be more eco-friendly is part of the prefab housing trend, and better greener prefab homes are produced with high-quality insulation. However, costs are still a big part of prefab homes and the price of the insulation can change other parts of the building process and decisions.
Costs Of The Insulation System
It is true that most prefab homes could be built with lower costs than stick built homes, however, when it comes to insulation both have the same costs.
For many of us building our new homes, costs will be the determining factor for most of our decisions. But, when it comes to the cost of the insulation system I would argue that the initial cost should not be the only deciding factor.
As mentioned above, the durability of the prefab house is another important factor, and insulation durability is a big part of it. Having durable and high-quality insulation that will perform for many years will have lower maintenance costs, lower energy costs, and lower health-related costs. All those combined will put some of the higher costs insulations in a much better spot if considered the long term effect.
So think of how your house will perform as a unit for the long term instead of looking at the costs of the building when it comes to the insulation.
The Best Insulation To Use In A Prefab House
If you wish to make the right decision and find the best thermal insulation to use in a prefab house go through the checklist above which will help you make your mind about it.
Overall the best insulation will be the one that fits your needs perfectly from all aspects.
On the other hand, I must say that for most houses the best overall insulation to use in a prefab house will be the Cellular materials, such as foamglas. These type of materials are just the best in all directions and will serve any house with the best performance for years to come.
However, as we explored above there might be other options available for different people and situations. Thus, I would really advise on making this process of finding the best insulation for your prefab home a methodical and considerable process.
I wish you only the best of luck in fitting the best insulation to use on your prefab home and hope that after my guide you will have the tools to do so.
Until next time
My Alternative House