Topic Earth4Energy Review - Avoid the Traps, Get the Facts
The two most common methods of installing radiant barrier are to Smart Energy Box Review either staple the attic foil to the bottom of your roof rafters or lay out the radiant barrier foil insulation over your existing batt or blown-in attic insulation. Either method will work well but your climate and how your home was constructed will help you decide which method of installation to use.
If you live in a cold or mixed climate laying the radiant barrier across the attic floor insulation is the easiest and most effective. In the Summer it will reduce radiant heat gain into the home and in the Winter it will reduce heat loss by radiation and minimize convective looping which is the cold heavy air falling through the attic insulation which reduces the R-Value of the attic insulation. Remember, foil insulation is NOT a substitute for regular attic insulation. They work together to reduce both radiant and conductive heat flow.
If you live in a warm or hot climate and have NO ductwork in the attic, then go ahead and lay the radiant barrier attic foil on top of your existing insulation. This is the best option for reducing both Summer heat gain and Winter Heat Loss. Make sure you have adequate insulation BEFORE adding radiant barrier. Once the radiant barrier is put over the blown-in insulation you cannot put more insulation on top. This will eliminate the benefit of a radiant barrier, which requires an air space on one side of the foil to be effective.
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