In today's society, the issues of energy consumption and greenhouse gas emissions in the construction industry are becoming increasingly severe. The energy use in the field of building construction accounts for a significant proportion of the global total energy consumption and greenhouse gas emissions. To address this challenge, improving the energy efficiency of buildings has become an urgent necessity. Concepts such as passive houses and zero-emission buildings are also starting to be applied in practice. Among the numerous measures to enhance building energy efficiency, building insulation is undoubtedly a crucial step.
In the pursuit of the highest insulation performance, many new insulation materials and solutions with low thermal conductivity values have been developed. Aerogel, a material, has successfully met this challenge. Although aerogel was developed as early as the 1930s, it has only recently gained widespread application in the construction industry.
So, what exactly is aerogel?
Aerogel is the lightest solid in the world and also the substance with the lowest density. Not only does it have a low density, but it also possesses a very prominent advantage - it is the best thermal insulator.
Essentially, aerogel is a type of gel. During its production process, liquid is replaced by gas without shrinkage, thus maintaining the integrity of its molecular structure. Despite being composed of over 98% air, aerogel possesses a very tough and sturdy texture. Due to these characteristics, aerogel is also known as "frozen smoke".
Application of aerogel in household buildings
The energy consumption and carbon dioxide emissions in the construction industry are issues that cannot be overlooked. Buildings account for 40% of total energy consumption and 36% of total carbon dioxide emissions. Reducing energy consumption in heating and cooling of buildings is an effective and beneficial measure to address climate change. To reduce this energy loss, it is necessary to adopt better insulation materials in accordance with new building codes.
Currently, a common insulation solution often involves increasing the thickness of the insulation material itself. However, this approach ultimately brings about some negative impacts. Economically, increasing material thickness raises costs; architecturally, it may affect the spatial layout and aesthetics of the building; environmentally, the use of more materials also imposes a certain burden on the environment. At this point, aerogel technology comes into play, offering more compact and high-performance insulation materials and solutions.
Through aerogel, people can overcome the two major obstacles that currently hinder the widespread application of silica aerogel in the construction field. The first obstacle is the poor mechanical properties of aerogel itself, and the second obstacle is its high production and manufacturing costs. With aerogel technology, we can create a new type of super insulation material. I believe that through the previous introduction, everyone has gained some understanding of what aerogel is and its applications in the home.

Advantages of aerogel insulation
1. High flexibility
Aerogel insulation products exhibit remarkable flexibility. They come in various forms, including aerogel concrete, aerogel boards, and aerogel mats. These products are typically supplied in roll form and are available in diverse sizes and specifications. Moreover, aerogel insulation products can be easily cut to the desired shape and size. They can be applied to any surface, whether it's walls, roofs, or floors, significantly simplifying inventory management. Even better, the production of aerogel insulation products is relatively straightforward.
2. No organic binder required
In general insulation materials, the primary function of the binder is to adhere all the fiber elements together. However, when the temperature rises above 200 degrees Celsius, these binders often decompose, causing the fibers to loosen. This situation is common in some buildings, such as when the external cladding is removed during maintenance, and the fiber insulation materials start to sag downward, making them unusable.
However, aerogel insulation materials do not have this problem because they do not require organic binders. This allows aerogel insulation materials to maintain structural and physical stability at higher temperatures.
3. Breathable and hydrophobic
Most insulation systems on the market, such as fiberglass, polystyrene, mineral wool, etc., tend to absorb moisture and retain it within the material. This ultimately makes them susceptible to corrosion under insulation (CUI). CUI occurs when moist insulation material comes into contact with any metal surface. However, using aerogel can easily avoid this situation because aerogel is hydrophobic. Functionally, aerogel can prevent water and moisture from penetrating into the insulation system through gaps and leaks.
Moreover, aerogel insulation materials, regardless of their form, exhibit breathability. When walls or equipment are heated, this breathability of aerogel insulation materials allows water vapor to pass through, thereby maintaining good air circulation.
4. The lowest K value
The K value, also known as the thermal conductivity, represents the insulating properties of a material. Generally, the lower the K value of a material, the better its insulating performance. Aerogel insulation systems boast the lowest K values, allowing them to be crafted into exceptionally thin profiles as required.
This unique property makes aerogel insulation materials particularly popular in areas where space is limited. Furthermore, the lightweight of aerogel insulation systems significantly reduces costs in material transportation, warehousing, and logistics. However, like any material, aerogel has its pros and cons. After exploring the benefits of aerogel, let's also examine its drawbacks.

Disadvantages and limitations of aerogel insulation
1. High cos
Compared to other insulation systems, aerogel insulation materials are slightly more expensive. Although their price is gradually decreasing with the expansion of aerogel production scale, the cost of aerogel insulation materials is still relatively high in the current market.
2. Temperature limit
The design temperature tolerance of aerogel insulation material can reach up to 650 degrees Celsius. If the temperature exceeds this range, other suitable types of insulation materials need to be used.

Characteristics of aerogel
1. Excellent thermal insulation performance
One of the most prominent characteristics of aerogel is its thermal insulation performance. Its insulation effect is 39 times better than that of the best glass fiber insulation material.
2. Extremely low bulk density
Aerogel holds the record for the lowest bulk density among all materials. Its bulk density is as low as 0.011 grams per cubic centimeter.
3. Unique thermal conductivity
Aerogel exhibits excellent thermal conductivity properties, which are attributed to its unique structure. Its thermal conductivity is very low, ranging from approximately 0.005 watts per meter per Kelvin to 0.016 watts per meter per Kelvin.
4. Obstruct heat conduction
The tortuous and porous path of the aerogel structure makes heat conduction very difficult, as it is difficult for heat to penetrate from one side of the aerogel to the other, whether through solids or gases.
5. Excellent comprehensive performance
Due to its high porosity, aerogel exhibits excellent physical, thermal, and acoustic properties, giving it a significant advantage over other traditional insulation materials.
6. Hydrophilicity
Aerogel exhibits hydrophilic characteristics.
7. Chemical stability
At temperatures as high as 950 degrees Celsius, aerogel does not react with any metal.

The practical characteristics of aerogel in household use
1. Enhance flexibility
Although aerogel is an excellent thermal insulator, it is also very brittle, which to some extent limits its practical applications. To overcome this limitation, aerogel is embedded into a structure similar to a fiber mat, allowing for both excellent thermal performance and strong flexibility.
2. Excellent thermal conductivity and breathability
The thermal conductivity of aerogel is 0.015 watts per meter per Kelvin, making it one of the best insulation materials in use today. Coupled with its high air permeability of approximately 0.05 meters, aerogel is highly suitable for the renovation of buildings.
3. Hydrophobicity
Aerogel is hydrophobic, which means it can repel water or any liquid.
4. Environmentally friendly and harmless
Aerogel insulation blankets do not contain any blowing agents, which means they will not release any harmful gases into buildings over time.
5. Long-term stability

After extensive testing, it has been found that the performance of aerogel will not degrade or be affected for 50 years or longer.
Application of Aerogel Insulation in Sustainable Building Construction
When discussing insulation in buildings, we often refer to the U-value. The U-value indicates the rate at which heat is lost through components of a building, such as walls, roofs, doors, and windows. The lower the U-value, the slower the heat generated by the heating system dissipates from the building, and the less energy input is required to maintain a comfortable indoor temperature.
Modern newly-built houses typically have a U-value of about 0.2 watts per square meter per Kelvin, whereas older buildings with solid walls have a U-value as high as 2.0 watts per square meter per Kelvin. Therefore, poor insulation performance can lead to a series of problems. Hence, upgrading and renovating these old buildings is not only important but also urgent.
1. Application of aerogel on walls
In buildings, the weak points for heat loss are mostly located on the external walls. The walls tend to absorb heat, but they cannot store it for long, which leads to the loss of heat to the external environment through the walls.
Using aerogel insulation materials on external walls can effectively prevent heat loss to the external environment. Aerogel blankets or boards can be used for insulation of both external and internal walls. For walls with humidity issues, aerogel provides a one-stop insulation solution. Due to its moisture-resistant properties, aerogel is also an ideal choice for damp walls.
2. Application of aerogel on roofs
If the roof of a house is not insulated or the insulation is ineffective, the house may lose up to 25% of its heat through the roof. By adopting high-quality insulation measures, this heat loss can be significantly reduced. The main function of a roof insulation layer is to keep warm in winter and cool in summer. Such an insulation layer also needs to save energy, reduce carbon dioxide emissions, and protect the house from structural damage.
Aerogel insulation materials can meet all these requirements by insulating the cavity of the roof. The specific method is to apply thin aerogel strips onto the roof.
3. Application of aerogel in door and window frames
In a typical building, door and window frames account for 25% of the building envelope. If these frames are not insulated, a significant amount of heat will be lost through the window frames. Therefore, insulating all frames in a house can prevent this thermal bridge phenomenon and improve thermal performance by 40%.
The hydrophobicity of aerogel insulation material provides an additional waterproof barrier for door and window frames, which can tightly seal the frames, thereby limiting or reducing heat loss associated with air leakage.
4. Application of aerogel on flooring
Aerogel insulation material boasts high thermal efficiency, substantial compressive strength, and a thin profile, rendering it an attractive option as an underfloor insulation material. Installing aerogel insulation under floors is effortless and swift, without impeding door installation.
In addition, for the renovation of basements, aerogel insulation material is also a very economical and practical solution. Aerogel insulation material can be used together with radiant flooring to save energy and achieve faster heating cycles.
5. Application of aerogel in high-performance windows
For efficient windows, air leakage and cold bridges are the two most important issues that need to be addressed. The insulation of windows is also crucial. For instance, if aerogel insulation is applied only to the surface of the wall and the edges of the window are neglected, it will result in a decrease in temperature at the window and its edges.

However, a decrease in temperature increases the risk of condensation in these areas. Therefore, it is necessary to add at least a small amount of insulation material to the edge areas of the windows, which can raise the temperature to a level sufficient to reduce the risk of condensation.
Aerogel products used in households
1. Aerogel particles
Aerogel insulation can be achieved by using aerogel particles. Simply fill these loose aerogel particles into the cavity of a double-layer wall to provide insulation. The thermal conductivity of aerogel particles is approximately 19 milliwatts per meter per Kelvin. This product makes it possible to renovate without damaging any building components. However, in order to achieve insulation, an appropriate filling method must be used to avoid generating dust, as dust can easily escape through small cracks.
2. Aerogel felt
Aerogel blanket can reduce heat loss by up to 60%. It exhibits very low thermal conductivity, with a heat transfer rate of 0.018 watts per meter per Kelvin. Aerogel blanket is most suitable for thermal insulation of interior walls. It is breathable and can also be applied to uneven surfaces. The thermal conductivity of aerogel blanket is as high as 15 milliwatts per meter per Kelvin. Aerogel blanket also boasts excellent fire resistance, with its fire performance classified as Class A2. Aerogel blanket can be used for thermal insulation of thermal bridges and window edges, as well as for the insulation of water pipes and solar water heating pipes.
3. Aerogel board
Aerogel boards are very similar to aerogel mats, with the difference being that aerogel boards are harder and thicker than aerogel mats. Aerogel boards are basically made by bonding several layers of aerogel mats or sheets together, or by laminating aerogel particles to form a sheet. Due to the involvement of several layers of aerogel mats, the thermal conductivity of aerogel boards is as high as 16 to 19 milliwatts per meter per Kelvin. It is most suitable for thermal insulation of interior walls.
4. Aerogel panel
By sandwiching aerogel particle fillers between two translucent or transparent panels, aerogel translucent panels are formed. These panels can be made of plastic or glass. Both sides of the translucent panels are tightly sealed to prevent dust from entering. The thermal conductivity of aerogel translucent panels is approximately 19 milliwatts per meter per Kelvin. Since the thermal conductivity is already high, the U-value of the panels remains relatively low.
The main highlight of this product is that it combines high thermal insulation performance with diffused light transmission.
5. Aerogel concrete
Aerogel concrete is an ultra-lightweight concrete system, primarily composed of aerogel particles or powder. The primary objective of producing aerogel concrete is to combine the high-strength characteristics of concrete with the excellent thermal insulation properties of aerogel.
Aerogel concrete, while possessing high compressive strength, also exhibits considerable thermal conductivity, making it suitable for use in the construction of exterior walls of multi-story buildings without the need for further insulation treatment. Aerogel concrete is an economical and practical solution, and it is also easy to handle.