Putting a sunshade in your car takes about 30 seconds once you know the steps, and it can drop your cabin temperature by roughly 27% and your dashboard surface temperature by 26%. The process varies slightly depending on whether you have an accordion-style shade, a pop-up shade, or side window shades, but the basics are the same: unfold, position against the glass, and secure.
Which Side Faces Out
If your sunshade has a shiny, metallic side and a darker side, the reflective side always faces outward toward the sun. This isn’t a style choice. The metallic coating bounces solar radiation away from the car before it passes through the glass and heats the interior. Flip it the wrong way and you’re trapping heat between the shade and the windshield instead of reflecting it away.
Installing an Accordion-Style Shade
Accordion shades fold into a compact stack of pleats. To set one up, unfold it completely and hold it with both hands. Position it against the inside of your windshield so it covers the entire glass surface and reaches as close to the edges as possible. Gaps along the sides let sunlight in and reduce the shade’s effectiveness.
Starting from the top center, tuck the upper edges into the corners where the windshield meets the roof. Then lower your sun visors to pin the top edge in place. The visors act as clamps, keeping the shade pressed flat against the glass. If the shade still wants to curl forward at the bottom, the steering wheel and dashboard usually hold the lower portion in position. Some accordion shades have small flaps or tabs along the edges that help them grip the windshield frame more securely.
Installing a Pop-Up (Twist-Fold) Shade
Pop-up shades use a spring-wire frame that twists into a small circle for storage, then springs open into a large panel. To use one, grip the folded disc with both hands and let it pop open. It will expand into a flat, roughly oval shape. Place it against the inside of your windshield with the reflective side facing out, then lower both sun visors over the top edge to hold it in place.
These shades tend to be slightly oversized for most windshields, which is intentional. The extra material curves against the edges of the glass and helps block light that would otherwise sneak around the sides. If your shade is noticeably too large or too small, you probably have the wrong size for your vehicle.
Getting the Right Size
Sunshades that don’t fit leave gaps that defeat the purpose. To find the right size before you buy, use a flexible cloth tape measure. Measure your windshield height and width directly through the middle, forming a plus sign. Measure from the inside edge of the rubber molding on one side to the inside edge on the other, not the full glass including the parts hidden under the trim. These two measurements will match you to the correct size on most packaging or product listings. Many sunshades are sold in standard sizes (small, medium, large) or by vehicle make and model, but measuring first saves you a return trip.
Setting Up Side Window Shades
Side window shades come in three main styles, and each attaches differently.
- Static cling shades stick to the glass without adhesive. Lightly mist the window and the shade with water, press the shade onto the glass, and smooth out any wrinkles or air bubbles with your hand. They peel off and reattach easily.
- Suction cup shades fold out from a compact shape. Dampen the suction cups, press them onto the glass, then unfurl the shade and hook or clip it to the cups. A quick lick of moisture on the suction cup creates a stronger seal.
- Retractable shades mount at the top of the window frame (often with adhesive brackets) and roll down like a tiny window blind. Once the bracket is in place, you just pull the shade down when you need it and let it retract when you don’t.
Some vehicles, particularly SUVs from BMW, Honda, Hyundai, and Kia, come with factory-installed rear window shades that clip into built-in hooks near the rear doors. If your car has small clips or hooks along the rear door frames, check your owner’s manual. You may already have a shade system you didn’t know about, or you can buy replacement clips and shades designed for your model.
Using Shades on Rear Windows While Driving
Windshield sunshades are strictly for parked cars. You remove them before driving. Side and rear window shades, however, are commonly left in place while driving, especially to protect kids in back seats. The legality varies by state. Most states only restrict tint and obstructions on the windshield and front driver/passenger windows. Rear passenger and rear windshield windows are generally more lenient, but not universally. Some states set specific light transmission requirements for rear windows: Minnesota requires 50% light to pass through, while South Dakota and Nebraska require 20%. Washington requires 24%, and Oregon requires 35%. If you plan to drive across state lines with side shades up, it’s worth checking the rules for each state on your route. As long as you have functioning side mirrors on both sides, most states permit reduced visibility through the rear glass.
Why a Sunshade Is Worth the Effort
A parked car in direct sun can reach extreme interior temperatures within minutes. A front windshield sunshade alone reduces dashboard surface temperature by about 26% and cabin air temperature by roughly 27%. When reflective material covers more of the car’s glass, the effect is even stronger. One study found that aluminum reflective covers over the full upper cabin reduced interior air temperature by nearly 18°C (about 32°F), and the average temperature of cabin components like the dashboard, steering wheel, and seat dropped by 70% compared to a car with no shading at all.
Beyond comfort, sunshades protect your interior from long-term damage. UV radiation passes through untreated glass and breaks down the materials inside your car over months and years. Leather dries out, loses flexibility, and cracks. Vinyl and plastic dashboards fade, become brittle, and develop the spider-web cracking pattern that makes an interior look decades older than it is. Even fabric seats and trim lose color with sustained UV exposure. A sunshade won’t block every ray, but it dramatically slows this process, especially on the dashboard and steering wheel, which take the most direct sun through the windshield.