There are several types of heat insulation material, each with its own advantages and disadvantages. Fiberglass is a type of non-flammable insulation material that is made from fine strands of glass. It is one of the best heat insulators available, but it can be dangerous to install because of glass powder and shards. Other options include rock wool, made from basalt, and slag wool, made from steel mill slag.

Cork is one of the oldest insulation materials and was once the most popular material in the refrigeration industry. Today, however, the lack of cork-producing trees has restricted its use to machine foundations and specialized applications. Cork is available in expanded slabs and granular form, with an average density of 110 to 130 kg/m3. Its mechanical resistance is around 2.2 kg/kg. However, cork is only useful up to a temperature of 65 degC and is expensive.

One way to assess the effectiveness of heat insulation materials is to look at the thermal conductivity. The R-value of an insulating material measures the resistance of the material to heat flow. This value will increase with increasing thickness. An excellent insulation material will have a high R-value. It is important to remember that the R-value is expressed as a proportion of the material thickness.

Another important feature of thermal insulation materials is their ability to reduce condensation. This happens when hot air comes into contact with cold walls. Thermal insulation material can prevent this from happening, which reduces the amount of heat lost through the hot water system. It can also minimize water pipe freezing.