Building insulation refers broadly to any object in a building used as insulation for any purpose. While the majority of insulation in buildings is for thermalpurposes, the term also applies to acoustic insulation, fire insulation, and impact insulation (e.g. for vibrations caused by industrial applications). Often aninsulation material will be chosen for its ability to perform several of these functions at once.
Thermal insulation in buildings is an important factor to achieving thermal comfort for its occupants. Insulation reduces unwanted heat loss or gain and can decrease the energy demands of heating and cooling systems. It does not necessarily deal with issues of adequate ventilation and may or may not affect the level of sound insulation.
The effectiveness of insulation is commonly evaluated by its R-value. However, an R-value does not take into account the quality of construction or local environmental factors for each building.
How much insulation a house should have depends on building design, climate, energy costs, budget, and personal preference. Regional climates make for different requirements.
Acoustic insulation or Soundproofing is any means of reducing the sound pressure with respect to a specified sound source and receptor. There are several basic approaches to reducing sound: increasing the distance between source and receiver, using noise barriers to reflect or absorb the energy of the sound waves, using damping structures such as sound baffles, or using active antinoise sound generators.
Two distinct soundproofing problems may need to be considered when designing acoustic treatments - to improve the sound within a room (Seeanechoic chamber), and reduce sound leakage to/from adjacent rooms or outdoors. Acoustic quieting, noise mitigation, and noise control can be used to limit unwanted noise. Soundproofing can suppress unwanted indirect sound waves such as reflections that cause echoes and resonances that causereverberation. Soundproofing can reduce the transmission of unwanted direct sound waves from the source to an involuntary listener through the use of distance and intervening objects in the sound path.