The first thing Phoenix heat meets.
We've measured a roof deck at 185.5 degrees in a Phoenix summer. A radiant barrier sits just under that roof and reflects the sun's heat back out before it bakes your insulation, your ducts, and everything else you count on. It isn't the whole answer, but it's the outermost layer of it.
Book My InspectionWe'll also tell you if your house is one where it isn't worth it.
What is a radiant barrier?
A thin, foil-faced layer installed under the roof deck that reflects radiant heat instead of absorbing it. The sun's heat arrives at your attic as radiation, the one type of heat insulation is weakest against, and bare wood soaks it up and re-radiates it down all day. Foil barely radiates at all, so the heat gets turned back at the roofline. It handles a different job than insulation does; the science page explains the three types of heat.
Does radiant barrier actually work in Phoenix?
Yes, and this is the climate it exists for. Its job is lowering attic temperature, and the benefit lands hardest on one situation: AC ducts running through the attic, which is most Phoenix homes. Cooler attic air means the coldest, most expensive air in your house is fighting less on its way to your rooms. In studies cited by the U.S. Department of Energy, radiant barriers reduced cooling costs by 5 to 10 percent in warm, sunny climates.
Worth it when
Where the physics pays off.
- Your AC ducts run through the attic
- Your roof gets full sun most of the day
- Your insulation and sealing are already handled
- Anything you store up there matters to you
We'd tell you to skip it when
And we will, at the inspection.
- Your roof is heavily shaded
- No ducts in the attic and the insulation is thin: depth comes first
- The budget only covers one fix, and it isn't this one
Is radiant barrier a scam?
The physics is real; the reputation was earned by how it gets sold. The scam stories almost always trace back to four things: door-to-door crews charging thousands for foil pitched as a substitute for insulation, with savings claims no study supports; foil laid flat on the attic floor, where dust settles on it and kills the reflectivity within a few years; spray-on "radiant barrier paint" that underperforms real foil; and cold-climate installs where there was never much heat to reflect. Under the rafters, fairly priced, on the right house, as one layer of a system, it's legitimate building science doing a specific job.
How does it go in?
The foil gets fastened to the underside of the roof framing, facing an air gap, which is what keeps it reflective for the long haul.
Your insulation stays untouched below, and attic ventilation keeps working the way it should.
Coverage documented, attached to your quote and invoice like every other job we do.
How much does a radiant barrier cost in Phoenix?
It depends on your roofline and how much of it is worth covering, which is what the free inspection works out. You get one flat quote before any work starts, and if the answer is that your house won't get its money's worth from a radiant barrier, the quote says that instead.
Before you book.
Does radiant barrier work in Arizona?
Yes, this is the climate it exists for. Its job is lowering attic temperature by reflecting the sun's radiant heat back out at the roofline, and the benefit concentrates on homes with AC ducts in the attic, which is most of Phoenix. Studies cited by the U.S. Department of Energy show cooling-cost reductions of 5 to 10 percent in warm, sunny climates.
Do I still need insulation if I get a radiant barrier?
Yes. A radiant barrier only addresses radiant heat; insulation depth handles the heat that conducts through, and air sealing handles the air that leaks through. It is one layer of the system, not a substitute for the others, and we will tell you which layer your house actually needs first.
Why not lay the foil on the attic floor?
Because dust settles on horizontal foil and kills its reflectivity within a few years. We install radiant barrier under the rafters, facing an air gap, where it stays clean and keeps working. Floor-laid foil is one of the reasons radiant barrier has a scam reputation.
Does a radiant barrier help in winter?
Its main job is summer. It reflects the sun's heat out of the attic, which is where Phoenix pain lives. Winter benefit is modest, and we won't pretend otherwise; in this climate the summer case is the whole case.
Book your free inspection.
Send your info and we'll text you to set up your visit. The inspection is free, and if a radiant barrier makes sense on your house you get a flat quote before any work starts.
Serving the Phoenix metro · Anthem to Goodyear to Queen Creek
Prefer to start by text? Text 480-725-3661
Book Your Inspection
We will confirm your visit by text or call.
AZ ROC #367670 · BPI-Certified Building Analyst - Technician · Flat quote before any work starts