The history of thermal insulation
Organic materials were the first available to build a shelter for people to protect themselves from bad weather conditions and to help keep them warm. But organic materials like animal and plant fiber cannot exist for a long time, so these natural materials cannot satisfy people’s long-term need for thermal insulation. So, people began to search for substitutes which are more durable In the 19th century, people were no longer satisfied with using natural materials for thermal insulation, they processed the organic materials and produced the first insulated panels. At the same time, more and more artificial materials start to emerge, and a large range of artificial thermal insulation materials were developed, e.g. rock wool, fiberglass, foam glass, and hollow bricks.
The significance of thermal insulation
Thermal insulation can play a significant role in buildings, great demands of thermal comfort result in a large amount of energy consumed for full-heating for all rooms.Around 40% of energy consumption can be attributed to the building, mainly consumed by heating or cooling. Sufficient thermal insulation is the fundamental task that ensures a healthy indoor environment and against structure damages. It is also a key factor in dealing with high energy consumption, it can reduce the heat flow through the building envelope. Good thermal insulation can also bring the following benefits to the building:
1. Preventing building damage caused by the formation of moisture on the inside of the building envelope. Thermal insulation makes sure that the temperatures of room surface don’t fall below a critical level, which avoids condensation and the formation of mould.According to the Building Damage reports, 12.7% and 14% of building damages were caused by mould problems.If there is no sufficient thermal insulation in the building, high relative humidity inside the building will lead to condensation and finally result in mould problems.
2. Producing a comfortable thermal environment for people living in the building. Good thermal insulation allows sufficiently high temperatures inside the building during the winter, and it also achieves the same level of thermal comfort by offering relatively low air temperature in the summer.
3. Reducing unwanted heating or cooling energy input. Thermal insulation reduces the heat exchange through the building envelope, which allows the heating and cooling machines to achieve the same indoor air temperature with less energy input.
Planning and examples
How much insulation a house should have depends on building design, climate, energy costs, budget, and personal preference. Regional climates make for different requirements. Building codes often set minimum standards for fire safety and energy efficiency, which can be voluntarily exceeded within the context of sustainable architecture for green certifications such as LEED.
The insulation strategy of a building needs to be based on a careful consideration of the mode of energy transfer and the direction and intensity in which it moves. This may alter throughout the day and from season to season. It is important to choose an appropriate design, the correct combination of materials and building techniques to suit the particular situation.
In the United States of America
The thermal insulation requirements in the USA follow the ASHRAE 90.1 which is the U.S. energy standard for all commercial and some residential buildings ASHRAE 90.1 standard considers multiple perspectives such as prescriptive, building envelope types and energy cost budget. And the standard has some mandatory thermal insulation requirements All thermal insulation requirements in ASHRAE 90.1 are divided by the climate zone, it means that the amount of insulation needed for a building is determined by which climate zone the building locates. The thermal insulation requirements are shown as R-value and continuous insulation R-value as the second index. The requirements for different types of walls (wood framed walls, steel framed walls and mass walls) are shown in the table.
To determine whether you should add insulation, you first need to find out how much insulation you already have in your home and where. A qualified home energy auditor will include an insulation check as a routine part of a whole-house energy audit. However, you can sometimes perform a self-assessment in certain areas of the home, such as attics. Here, a visual inspection, along with use of a ruler, can give you a sense of whether you may benefit from additional insulation.
