How insulation works

  • To understand how insulation works, it helps to understand heat flow, which involves three basic mechanisms-- conduction, convection, and radiation. Conduction is the way heat moves around through materials, such as when a spoon placed in a hot cup of coffee conducts heat through its handle to your hand. Convection is the way heat circulates through liquids and gases, and is why lighter, warmer air rises and cooler, denser air sinks in your home. Radiant heat travels in a straight line and heats anything solid in its path that absorbs it energy. 


  • Most common insulation materials work by slowing conductive heat flow and--to a lesser extent-- convective heat flow. Radiant barriers (which are not insulation products) and reflective insulation systems work by reducing radiant heat gain. To be effective, the reflective surface must face an air space. 


  • Regardless of the mechanism, heat flows from warmer to cooler until there is no longer a temperature difference. In your home, this means that in winter, heat flows directly from all heated living spaces to adjacent unheated attics, garages, basements and even to the outdoors. Heat flow can also move indirectly through interior ceilings, walls, and floors-- wherever there is a difference in temperature. During the cooling season, heat flows from the outdoors to the interior of a house. 


To maintain comfort, the heat lost in the winter must be replaced by your heating system and the heat gained in the summer must be removed by your cooling system. Properly insulating your home will decrease this heat flow by providing an effective resistance to the flow of heat. 

Types of Insulation

  • To choose the best insulation for your home from many types of insulation on the market, you'll need to know where you want or need to install the insulation, and what R-value you want the insulation to achieve. Other considerations may include indoor air quality impacts, life cycle costs, recycled content, embodied energy, and ease of installation

Insulation Materials

  • Insulation materials run the gamut from bulky fiber materials such as fiberglass, rock and slag wool, cellulose, and natural fibers to rigid foam boards to sleek foils. Bulky materials resist conductive and -- to a lesser degree-- convective heat flow in a building cavity. Rigid foam boards trap air or another gas to resist conductive heat flow. Highly reflective foils in radiant barriers and reflective insulation systems reflect radiant heat away from living spaces, making them particularly useful in cooling climates. Other less common materials such as cementitious and phenolic foams and vermiculite and perlite are also available. 


  • A home energy checkup helps owners checkup helps owners determine where their house is losing energy and money- and how such problems can be corrected to make the home more energy efficient. 

Benefits of insulation

  • Cleaner air 

  • Safer for animals 

  • Helps keep cool air inside and hot air outside 

  • Moisture resistant  (Prevents molds & odors)

  • Safer, fire proof , and heat reduction in the home 30%