Attic Insulation Radiation Vs Conduction

Traditional insulation blocks convection and conduction.

Attic insulation radiation vs conduction.

The matter is present around us in three states solid liquid and gas. Positioning a radiant barrier in the attic ceiling allows it to reflect radiant heat entering through the roof to keep the attic significantly cooler. Radiation occurs when electromagnetic rays transfer heat into an object like when the sun heats up concrete or sand and they re too hot to walk on. This is because foil insulation reduces radiant heat gain rather than slowing conductive and convective heat flow.

Insulation works by slowing the transfer of heat which can move in three ways. The transfer of heat by contact with solid objects such as the ceiling walls or floor is called conduction see figure 1. A radiant barrier blocks the third type of heat transfer. Conduction convection and radiation.

While conduction is the transfer of heat energy by direct contact convection is the movement of heat by actual motion of matter. The barriers consist of a highly reflective material that reflects radiant heat rather than absorbing it. Despite this it s easy to overlook the benefits of proper attic ventilation radiant barriers and energy efficient insulation. Once temperatures soar that high there is little that the conventional insulation types like batt and blown combatting convective air transfer can do to stop the heat before it makes its way to the living spaces of your home.

While heat is radiated and conducted in all directions it always moves from hot areas to cold areas. For heat to travel from your body through your down jacket it has to move by conduction through the tiny feather fibers that are in contact with each other. Considering the large square footage of attic space in the average house and a roof s exposure to direct sunlight an attic is a significant source of heat transfer into the conditioned space of a home source. Convection is when heat is transferred through the air inside the attic and heats the insulation and conduction occurs when heat moves through the insulation to the building below.

Conduction is best represented through heating a pot of water on the stove. A good thermal barrier along a building envelope such as high r value insulation in the walls attic and raised floors as well as multi paned glass help to reduce conduction. Radiation infra red is augmented by convection and conduction. They don t however reduce heat conduction like thermal insulation materials.

By the end of a hot summer day expect the air temperature in some spots of your attic to reach over 140 degrees. It is when something is heated by something else which also can heat something else. If you re looking to improve your energy use check out these five different ways to make your attic more energy efficient.