EcoFoil How Reflective Foil Works
Radiant Barrier Foil Insulation
What is a radiant barrier?
A radiant barrier is an insulation system that utilizes a reflective foil insulation to BLOCK radiant heat energy opposed to conventional mass insulations that work by absorbing heat energy. In order to fully understand how radiant barriers work and how reflective insulation can benefit you, the following information has been provided for your knowledge.
How is heat transferred?
To best understand how a radiant barrier works we must first understand the different ways that heat is transferred.
There are three ways in which heat is transferred from warm spaces to cold spaces:
Conductive: the transfer of heat flowing through a solid or fluid material.
Convective: the transfer of heat which involves the physical movement of air when it is warmed
Radiant: the movement of invisible heat rays from a warm surface to a cooler surface through an air space
How is reflective insulation different from conventional insulation?
Reflective insulation works differently from conventional insulation products such as fiberglass insulation, cellulose insulation and foam insulation. These products work by slowing down or resisting heat energy. The rate of resistance gives an insulation material it’s r-value. These types of insulation do not block heat energy they only slow it down.
Conventional insulations do not insulate against RADIANT heat transfer.
Radiant heat that is transferred in your home or building enters or escapes in three directions of HEAT FLOW. The charts below show the rate of HEAT GAIN or HEAT LOSS in each instance.
The charts show that radiant heat transfer is responsible for the largest amount of heat loss or gain in a building structure. Considering the fact that fiberglass, cellulose and styrofoam only guard against heat conduction and convection, we can understand how much energy is lost or gained through radiant transfer.
 Conductive  Radiant  Convective
What classifies as a radiant barrier?
According to the Department of Energy , for a product to be classified as RADIANT BARRIER it must have an emission of 10% or less and a reflectance of 90% or more.
A radiant barrier utilizes a foil surface to reflect radiant heat rays back toward the source.
A foil surface has two properties that enable it to reflect radiant heat energy.
1. Reflectivity - to bend back; to give a backward turn to; to throw back; especially, to cause to return after striking upon any surface; as, a mirror reflects rays of light.
2. Emissivity - amount of heat which is "emitted" or radiated off of a surface to the surrounding air.
Our radiant barrier products have an emission of only 3% and a reflectance of nearly 97% which exceeds the Department of Energy’s minimum classification requirements.
For a radiant barrier to work properly the reflective side must face an open air space of at least 3/4”.
Below are some common places a radiant barrier would be installed…
· Over top of an attic floor.
· To the underside of the rafters in an attic.
· Around the exterior of a house as a house wrap.
Do I need a perforated or solid radiant barrier?
In certain applications a radiant barrier MUST be perforated to allow water vapor to pass through it. For example, when used on the attic floor the perforated radiant barrier must be used. This is necessary because during the cooler months, if there is no effective vapor retarder at the ceiling, water vapor from the living space may condense (and even freeze) on the underside of a radiant barrier lying on the attic floor and cause water damage to the ceiling and any existing attic floor insulation.
How does radiant barrier work in the summer and the winter?
A radiant barrier works by reflecting radiated heat rays back towards the source they originated from. To help understand how why it works in both climates we have explained each situation below.
Summer
During the summer, the main source of wasted energy in your home is cause by the heat gain when the roof and walls absorb radiant heat from the sun. This heat is then conducted toward the attic space and eventually radiated into the attic. Most of this radiated heat can be reflected back towards the outside when a radiant barrier is installed. Without a radiant barrier the heat will be collected by the attic space and interior of the home. Fiberglass insulation does very little to stop radiated heat. In addition, the air conditioner and ductwork also absorb attic heat, which is then blown into the house. A properly installed radiant barrier blocks 97% of this radiant heat which will save money on cooling the home.
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Winter
During the winter, the main source of wasted energy in your home is caused by heat that is lost by your home when it naturally rises from inside the home and escapes through the ceiling into the attic and then out through the roof. Heat is radiated in all directions through the ceiling, walls and floor. Obviously the more heating energy that is lost, the more heating energy it takes to replace it. A radiant barrier reduces this wasted energy by reflecting most of the rising heat back towards the interior of the building.
Radiant Barrier Benefits
- Foil insulation reflects 97% of radiant heat making your home or building more energy efficient
- Unaffected by humidity or moisture
- Class 1 / Class A fire rating (EcoFoil radiant barrier passes the newest fire test in the industry, ASTM E84-2009)
- Non-toxic / non-carcinogenic
- Environmentally safe
- Fiber free
- Durable and lightweight
- Easy to install and maintenance free
- Lowers heating and cooling costs
- Clean installation/no respirators or special clothing
- Easy handling
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