Best Window Treatments to Keep Heat Out and Lower Energy Bills

The best energy efficient window treatments for cutting summer cooling costs are double cell cellular shades, followed by lined Roman shades, solar shades, and multi layer thermal curtains, each blocking heat transfer at different levels depending on design and how they're used.

Why Window Coverings Matter for Energy Bills

Windows are one of the biggest weak points in a home's insulation. Uncovered glass lets heat pour in during the afternoon and lets conditioned air seep out, forcing an air conditioner to work harder. Swapping in the right shade or curtain won't replace proper insulation or new windows, but it can meaningfully reduce how often the AC kicks on, especially in rooms that get direct sun for several hours a day.

Cellular Shades Lead the Pack

Cellular shades, sometimes called honeycomb shades, use a distinctive pleated shape that forms pockets of trapped air along the window. Those air pockets act as a buffer between the glass and the room, which is why they're generally considered the most effective option for blocking heat. They come in single cell and double cell versions, and double cell shades provide noticeably more insulation because they contain two rows of air pockets instead of one. Many models now come in configurable sizes and colors, with continuous cord, cordless, or motorized smart operation, and most can be installed in about 15 minutes with included hardware.

Roman Shades and Solar Shades Offer a Middle Ground

Lined Roman shades rank as the second best barrier against heat gain, provided you choose a version with a proper liner rather than a purely decorative fabric. They suit homeowners who want a tailored, upscale look without giving up performance entirely. Some come with a choice of liners, including thermal sateen, alongside solid or patterned fabric options.

Solar shades work differently. As a variation on roller shades, they filter out a portion of incoming sunlight rather than blocking it completely, so they won't seal out heat as thoroughly as cellular or lined Roman shades. Denser, more opaque fabrics block more heat, while lighter weaves let more light and warmth through. Their advantage is that they preserve some of the view outside, and several products on the market claim to block up to 99 percent of UV rays while still letting in daylight.

Where Thermal Curtains Fit In

Thermal curtains rank last for solo performance, but that doesn't mean they're not worth considering. They tend to work best paired with cellular or solar shades underneath, adding another layer against heat and glare. Anyone relying on curtains alone should look for two or three layer panels rather than single layer fabric, since the extra layers do most of the insulating work. Some versions include a removable felt liner and claim full blackout coverage along with thermal protection, and they're often sold in pairs across multiple sizes and colors.

Comparing the Options

Getting the Timing Right

The type of shade or curtain matters less than how it's used. Opening window treatments at night, when outdoor temperatures drop, and closing them again once the day starts heating up helps limit how much warm air transfers indoors. Done consistently through the summer, that habit alone can reduce how often an air conditioner runs, which shows up as lower cooling costs over time. Combining that routine with a higher performing shade, like a double cell cellular option, tends to produce the biggest savings.

So Which Treatment Actually Pays Off

There's no single right answer for every home. A room with brutal afternoon sun probably benefits most from double cell cellular shades or a cellular and curtain combination, while a space where the view matters more might do better with a solar shade despite the tradeoff in heat blocking. The honest approach is to match the treatment to the room's exposure and your own priorities around light, privacy, and cost, rather than assuming one product solves every window in the house.