The reflective (shiny) side should always face the heat source and an air space.
(Most Reflectix® products are reflective (shiny) on both sides.) The reflective insulation benefit is derived from the interaction of the highly-reflective surface with the air space. If the reflective surface is in contact with another building material, it becomes a conductor (transmitting the energy by conduction).
The reflective (shiny foil) side should always face the heat source. If you want to keep your space cool by reflecting the summer sun, face the foil outward. If you are in a cold climate and want to reflect indoor heat back into your space, face the foil inward.
Yes, the direction matters significantly. The rule of thumb is to face the paper or foil vapor barrier toward the conditioned (heated or cooled) living space. This prevents warm, moist air from passing through the insulation and condensing on cold surfaces, which can lead to mold and structural rot.
The paper side (vapor barrier) of insulation should always face toward the heated, conditioned living space to prevent moisture from trapping inside walls and causing mold. In walls, this means the paper faces inside toward the room; in attics, it faces down; and in crawl spaces, it faces up.
Installing insulation with the wrong facing direction can lead to serious problems, including moisture buildup, mold, wood rot, and reduced insulation efficiency. Taking the time to install insulation correctly preserves your home's energy efficiency and prevents costly repairs down the line.
Cons of Reflective Insulation
As a general rule, install foil-faced insulation boards with the foil facing the heated or conditioned living space to retain heat, or facing the exterior to block radiant heat from the sun. For the reflective foil to work as a radiant barrier, you must leave a minimum 𝟏/𝟐 inch air gap between the foil and the next surface.
The facing should always face the warm side of the wall (toward the living space in cold climates). This prevents warm, moist air from penetrating into the wall cavity where it could condense and cause problems.
Because spray foam can trap moisture, hide the condition of the roof, make it difficult for surveyors to inspect, which means risks like timber decay, dry rot, and not forgetting increased fire risk. If you've got it or you're buying a property that does, this is something you need to know upfront.
Mice are curious and always searching for safe, snug, and warm nesting sites. Attics filled with blown-in insulation provide an excellent option–from the mice's point of view. As long as there is a ready food source. Mice are omnivorous and will eat and chew on almost anything including wood and electrical wires.
Unless you like the feeling of living in a cave, (which some people do), put the reflectix in your closets, cupboards and cabinets that are at your outside walls. It's a good idea to use velcro so that you can look between the reflectix and wall every once in a while to make sure there isn't moisture back there.
Reflectix is excellent at reflecting radiant heat but is generally a poor standalone insulator. Its core insulating value (R-value) is only about 1.11.11.1 on its own. To achieve higher R-values (up to R-21), it must be installed with a strictly calculated, enclosed air space and faces the specific source of heat.
Yes, faced or unfaced insulation matters significantly depending on your climate, local building codes, and the specific location you are insulating. The facing acts as a vapor barrier (or retarder) to prevent moisture from condensing inside your walls.
When it comes to foil insulation, it's generally recommended to leave an air gap of at least 25mm (1 inch) between the foil layer and the surface it's installed on. This allows the foil to reflect radiant heat, rather than simply absorbing it.
People put foil on doorknobs as a viral, low-tech alarm system. The crinkling foil is intended to make a loud noise if someone tries to turn your handle, or to show visible signs of tampering (like ripped or missing foil) to alert you that someone tried to get in.
Aluminum foil is generally safe for everyday use, but it can be problematic when exposed to high heat or acidic foods, which cause aluminum to leach into your meal. It also poses risks for improper food storage, uneven baking, and environmental waste.
The Reflectix® family of tapes are designed specifically for use with the Reflectix® Reflective Insulation products. The Foil Tape is for seaming our Double Reflective and Single Reflective Insulations. Our White Poly Tape is specified for the white side of our Single Reflective Insulation.
The healthiest, non-toxic insulation for your home is natural sheep's wool or hemp insulation. These materials contain no chemical binders or formaldehyde, actively regulate indoor humidity to prevent mold, and do not off-gas.
I use Reflectix in the winter months to keep the warm air in and in the summer to keep the heat out. I used newspaper to make a pattern on all the windows in my RV. I cut the Reflectix to the pattern sizes and placed velcro at the top and bottom to attach them.
Yes, the direction matters significantly. The rule of thumb is to face the paper or foil vapor barrier toward the conditioned (heated or cooled) living space. This prevents warm, moist air from passing through the insulation and condensing on cold surfaces, which can lead to mold and structural rot.
What time of year is Insulation cheapest?
Faced insulation
Kraft or foil facedFaced insulation is a batt or roll of fiberglass insulation with an attached kraft paper or foil facing. Kraft and standard foil facings can burn and must not be left exposed.