Reflective Heat Barrier - How It Works?
This is RADIANT BARRIER,
Since we don't have a big tree, we are going to the next best thing. REFLECT the infrared energy AWAY from the home. All radiant barrier does is REDUCE the amount of heat entering the home. Once again reducing the amount of heat entering the home and helping to reduce the energy needed to remove the heat (cooling the home) and make the home more comfortable.
HOW Does it WORK?
Now, here is the tricky part...stay with me. Infrared or radiant heat is INVISIBLE. Think of a mirror. if you hold it up the sun and reflect the light on your arm. You SEE the light, but your FEEL the radiant heat. At night your home is instantly easier to keep cool right? Why? Because when the sun went down the radiant heat gain on the home was reduced. The AIR temperature may only drop a couple of degrees.
You probably have some radiant barrier -
Do you have the shiny silver flex duct in your attic? This is an insulated tube with a radiant barrier covering. The radiant barrier helps reduce the amount of heat from entering the ductwork and effectively makes the R-Value of the insulation greater. Conceptually, this is what we are trying to achieve for your whole attic.
How WELL does it work?
It depends on the home and many other factors. But basically the more roof you have the greater the impact. For example: Installing foil insulation on a 1-Story ranch style home will have a GREATER impact than a stacked 2-story home with a small attic. Remember, your home is a BOX with 5 basic exterior sides. The greater the roof portion, the greater potential impact.
The "Truth"
Remember, reflective foil insulation is like "Shade". How much electricity would you save if your roof was shaded? This the most you will save with by installing a radiant heat barrier in your attic. Nothing more, probably a little less. On a 90º day are you still going to run the air conditioner? Yes, It's 90 degrees. It WILL run less and more efficiently though. However, on a 75º day the radiant barrier might just keep you from having to run your A/C at all. A foil product will work better than a radiant barrier paint, ceramic paint additive or microspheres.
So HOW MUCH savings?
As the example above illustrates, a 1-story home might have a 15-20% reduction and a 2 -story tall home might only have a 5-10% savings. HOWEVER, the DOLLAR PAYBACK is constant. On a 2-story home, you might have only HALF the savings compared to a 1-story home BUT you also probably installed only HALF the amount of foil and had a lower total installation cost.
