When discussing building insulation, the U-value is commonly mentioned. The U-value indicates the rate at which heat escapes through building components such as walls, roofs, windows, and doors. The lower the U-value, the slower the heat loss from the building, and the less energy required to maintain a comfortable indoor temperature. 
Modern newly built houses typically have a U-value of about 0.2 watts per (square meter·kelvin), whereas older buildings with solid walls can have U-values as high as 2.0 watts per (square meter·kelvin). Poor insulation performance thus leads to a range of problems. Therefore, upgrading and retrofitting these older buildings is not only important but should also be a top priority. 
1. Application of aerogel in walls 
In buildings, the weak points for heat loss are mostly located in the exterior walls. Walls tend to absorb heat but cannot store it for long periods, resulting in heat being lost through the walls into the external environment. 
Using aerogel insulation materials on exterior walls can effectively prevent heat loss to the external environment. Aerogel blankets or panels can be used for thermal insulation in both exterior and interior walls. For walls with moisture issues, aerogel offers an all-in-one insulation solution. Due to its moisture-resistant properties, aerogel is also an ideal choice for damp walls. 
2. Applications of Aerogels on Roofs 
If a house's roof is not insulated or poorly insulated, up to 25% of the heat can be lost through the roof. High-quality insulation significantly reduces this heat loss. The primary function of roof insulation is to keep the house warm in winter and cool in summer. Such insulation also helps save energy, reduce carbon dioxide emissions, and protect the building from structural damage. 
Aerogel insulation materials can meet all these requirements by insulating the cavities in roofs, specifically by applying thin aerogel strips to the roof surface. 
3. Application of Aerogel in Window and Door Frames 
In a typical building, window and door frames account for 25% of the building envelope. If these frames are not insulated, significant heat loss can occur through the frame. Therefore, insulating all framing in a house can prevent this thermal bridging and improve thermal performance by 40%. 
The hydrophobic property of aerogel insulation material provides an additional waterproof barrier for window and door frames, enabling tight sealing that limits or reduces heat loss associated with air leakage. 
4. Applications of Aerogel on Flooring 
Aerogel insulation materials offer high thermal efficiency, excellent compressive strength, and a thin profile, making them an attractive choice for underfloor insulation. Installing aerogel insulation beneath floors is easy and quick, without interfering with door installation. 
In addition, aerogel insulation is also a highly cost-effective solution for basement renovations. Aerogel insulation can be used in conjunction with radiant floor heating to save energy and achieve faster heating cycles. 
5. Applications of Aerogels in High-Efficiency Windows 
For high-performance windows, air leakage and thermal bridging are the two most critical issues to overcome. Window insulation is equally important. For example, if aerogel insulation material is applied only to the wall surface while neglecting the window edges, it will result in reduced temperatures at the window and edge areas. 
However, a drop in temperature increases the risk of condensation in these areas. Therefore, it is necessary to add at least a small amount of insulation material along the window edges to raise the temperature sufficiently and reduce the risk of condensation.