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Install a Radiant Barrier

Energy Efficiency, Energy Efficiency, Insulation and Energy Conservation November 18, 2011 Sonia


By Matt Weber



Reflecting on Energy Savings.



If you’ve ever attended a potluck dinner, then you can attest to the heat-retention properties of aluminum foil. Without it, the world would be subjected to a lot of cold casseroles. Aluminum foil is widely used as a means of thermal insulation by acting as a reflective barrier. Similar in concept, a reflective barrier can also be used in homes and commercial buildings to reduce heat transfer and save on heating and cooling costs.

Here’s how it works: On a hot day, the sun heats a home’s roof, which radiates heat towards the attic floor and conventional insulation. Those materials emit radiant heat to varying degrees throughout the house. A hotter attic means a hotter house, so radiant barriers are used to block the sun’s rays from transferring heat to your attic. A product such as Enerflex Radiant Barrier can reflect up to 96-percent of the sun’s energy, reducing the attic temperature by as much as 30 degrees. This helps contribute to a more consistent and comfortable indoor temperature as less heat moves through the attic floor into the living area. As a result, there is less need to crank up the air conditioner.

enerflex 1 Install a Radiant Barrier

The material we installed for this project was Enerflex Radiant Barrier, available in both rolls and panels (16” or 24” O.C.).

Furthermore, this two-way reflective barrier behaves similarly in the winter. In cool weather, Enerflex helps keep radiant energy from leaving the home, reducing heat loss so you don’t have to blast the furnace as much.

A variety of radiant barrier products are on the market, but the EHT staff chose the new Enerflex brand for a recent project based on its design as an easy-to-install DIY product.

In a single afternoon, we had an attic ready and reflecting.


Installation Dos and Don’ts

Enerflex is available in flat panels as well as rolls to meet the installation needs of your roof. The product is made from two layers of metalized film, laminated and reinforced with a plastic scrim to reduce tears and punctures.

enerflex 2 Install a Radiant Barrier

Start at the bottom of the rafters and work upward.

Utilizing three thin metal backer rods each, the Enerflexpanels friction-fit between the roof rafters, either 16 or 24 in. on-center. No tools are required to install the panels. Simply insert one edge of the panel against the roof framing, where it meets the sheathing, then give the panel a slight bow and tuck the other edge against the side of the next rafter. That’s all there is to it. The tension on the backer rods holds the panels in place. Start at the bottom of each rafter channel and work your way upward, overlapping the panels by 1 or 2 in.

enerflex 3 Install a Radiant Barrier

The panels friction-fit between the roof rafters.

The rolls of flexible material are for covering oddly spaced rafters or complicated framing around peaks, dormers, tight corners, etc. Simply unroll the material and pull it tight, tacking it to the underside of the roof rafters every few inches with a staple gun.

enerflex 7 Install a Radiant Barrier

Tightly spaced framing can be covered with the flexible sheet product available in rolls.

Both the panels and the rolls can easily be cut with a utility knife or heavy-duty snips to make angles or to cover short rafter spans.

enerflex 8a Install a Radiant Barrier

The sheet can be stapled in place over the roof framing.

enerflex 8b Install a Radiant Barrier








enerflex 4 Install a Radiant Barrier

The radiant barrier can easily be cut with heavy-duty scissors, snips or a utility knife.