Exterior Solar Shades vs. Interior Blinds: Keeping a Portland Home Cool

46%

Solar heat gain cut by insect screens mounted outside (DOE / PNNL)

14%

The same screens mounted inside

65–97%

Range of heat blocking in solar screen fabrics (Phifer)

We started our 2020 staycation series with windows, because that’s where a house gains most of its summer heat. Six years and one record heat wave later, the advice is the same, with better numbers behind it: if you want a cooler room, stop the sun on the outside of the glass.

Why shading outside the window works better

Sunlight that passes through glass turns into heat inside the room. An interior blind catches some of it, but the heat is already indoors. An exterior shade stops it first. According to the Department of Energy’s Building America Solution Center, exterior attachments “block sunlight before it passes through the window, so they are typically more effective at reducing solar heat gain,” and “because the screen is located outside the window, solar heat absorbed by the screen remains outside the home.”

The same guide cites research on plain insect screens: 46% less solar heat gain mounted outside, 14% mounted inside. Purpose-made solar fabrics go much further.

How exterior solar screens work

A solar screen is a woven mesh designed to block heat and UV while letting you see out. Fabrics vary: Phifer, one of the largest screen makers, describes solar screen options from 65% to 97% heat blocking. A tighter weave blocks more sun and gives up some outward view; Phifer suggests higher protection for hot, sunny exposures and lower percentages where visibility matters more.

On the outside of a house, solar fabric usually rolls on a retractable shade, so it comes down for the afternoon and goes back up at dusk. Zip-style systems lock the fabric’s edges into side tracks so it stays put in wind. We install SummerSpace FlexShade and Futureguard Vivista systems; see motorized and solar screens for both.

Exterior solar shades vs. interior blinds vs. awnings

Where exterior shades pay off most

• West-facing windows and sliders that take the low afternoon sun an awning can’t reach.
• Glass walls and big picture windows that heat a whole room.
• Home offices and TV rooms where glare is the real problem.
• Rooms with wood floors and furniture you want to protect from UV fading.

Privacy, day and night

During the day, you can see out through a solar screen but people outside have a hard time seeing in. At night, with the lights on inside, that reverses. If nighttime privacy matters, pair exterior shades with interior curtains, or choose a solid fabric for the rooms that need it. Our patio privacy screens guide covers solid and mesh fabrics for outdoor rooms.

Motorized or manual

Both work. Motorized shades come down with a button or remote, which makes it more likely you’ll actually use them every afternoon. Manual shades cost less. Either way, the price depends on the width and height of each window, the system, the fabric and the controls, so we quote after a free consultation; what affects cost explains the factors.

If you want to keep the air conditioning bill down, stop squinting at your screen, and keep your view, give us a call at (503) 226-2761. We’d be happy to talk through the options.

Originally published April 29, 2020, as the first post in our staycation home-improvement series. Rewritten and expanded October 22, 2026.