{"id":550,"date":"2026-10-21T12:38:37","date_gmt":"2026-10-21T04:38:37","guid":{"rendered":"http:\/\/www.dviason.com\/blog\/?p=550"},"modified":"2026-10-21T12:38:37","modified_gmt":"2026-10-21T04:38:37","slug":"what-are-the-cooling-effects-of-different-types-of-window-glass-in-summer-45f0-d4dcb2","status":"publish","type":"post","link":"http:\/\/www.dviason.com\/blog\/2026\/10\/21\/what-are-the-cooling-effects-of-different-types-of-window-glass-in-summer-45f0-d4dcb2\/","title":{"rendered":"What are the cooling effects of different types of window glass in summer?"},"content":{"rendered":"

If you\u2019ve ever walked into a sun-drenched office on a 95-degree summer afternoon and felt like the walls around you were radiating heat instead of insulation, you know how big a difference window glass can make to your space\u2019s summer cooling needs. For years, I\u2019ve worked with homeowners, small business owners, and property managers as part of our Summer Cooling team, helping them cut down on unnecessary AC costs and keep indoor spaces comfortable without cranking up the thermostat. A question I get asked all the time is: \u201cWhat kind of window glass actually works to cool my space in summer?\u201d It\u2019s not a one-size-fits-all answer, and the right choice depends on how your space is used, the direction your windows face, and even the local climate. Let\u2019s break down the different types of window glass and their real-world cooling effects, based on years of on-site installations and customer feedback. Summer Cooling<\/a><\/p>\n

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First, let\u2019s start with the basics most people don\u2019t know: all window glass interacts with sunlight in three ways. Some light passes through (transmitted), some bounces off (reflected), and some is absorbed. The heat that matters most in summer is infrared (IR) radiation\u2014this is the invisible light that carries heat from the sun, and it\u2019s the main reason your indoor space heats up even when you close your windows. Your goal for summer cooling is to block as much of that IR heat as possible while still letting in visible light (you don\u2019t want dark rooms that need artificial light during the day). That\u2019s where the differences between glass types really come in.<\/p>\n

Let\u2019s start with single-pane clear glass, the kind you\u2019ll find in old homes, apartment rentals, or budget windows. This was the standard for decades, and its cooling performance is pretty basic. Clear glass transmits about 85% of visible light and 75% of infrared heat. That means on a 90-degree day, almost three-quarters of the sun\u2019s heat passes right through the glass into your space, forcing your AC to run overtime just to keep up. I can\u2019t tell you how many customers with single-pane windows tell me their electricity bills jump by $150 or more in July. The only upside? It\u2019s cheap upfront, and it lets in a lot of light. But for summer cooling, it\u2019s one of the least effective options out there. We rarely recommend single-pane clear glass for any space that\u2019s used regularly in warm weather, unless you\u2019re on an extremely tight budget and can upgrade later.<\/p>\n

Next, double-pane clear glass, which has become the standard for new construction in most areas. Double-pane means two layers of glass with a gas gap (usually argon) between them, which does a better job of insulation than single-pane. But when it comes to summer heat, even double-pane clear glass only blocks about 25% of infrared heat, according to data from the Department of Energy (DOE). The gas gap helps prevent heat transfer from conduction, but it does almost nothing to stop the sun\u2019s IR radiation from passing through the glass itself. So you still get most of the heat coming through the window, just less of it from outside air. For someone with double-pane clear windows, you might see a 10-15% reduction in AC costs compared to single-pane, but that\u2019s still not enough if you\u2019re looking for meaningful summer cooling. We often see customers with this glass type complaining that their west-facing rooms (which get direct sun in the hottest part of the day) are still uncomfortably warm\u2014this is why.<\/p>\n

Now, the first game-changer for summer cooling: low-emissivity (low-e) glass. This is the type we install most often for residential and commercial clients, and it\u2019s designed specifically to block infrared heat while letting visible light through. Low-e glass has a microscopic, transparent coating on the surface of the glass that reflects IR radiation back toward the outside. There are two main types of low-e glass, and their cooling effects are tailored for different seasons and climates. High-summer low-e (also called \u201chard-coat\u201d or \u201csolar control\u201d low-e) is what we use for warm climates: it\u2019s optimized to reflect up to 60% of incoming IR heat, while still transmitting around 70% of visible light. That means your room gets natural light without the extra heat. I had a client last year with a 1,200-square-foot retail space in Phoenix; we swapped their old double-pane clear glass for high-summer low-e, and their AC bill dropped by 28% in the first three months. The other type, winter low-e, is designed to keep heat inside during cold months\u2014you don\u2019t want that for summer, because it will trap the sun\u2019s heat inside your space. That\u2019s why it\u2019s so important to make sure you\u2019re specifying the right low-e coating for your climate. One mistake we see a lot of customers make is choosing the wrong low-e type, and ending up with higher cooling costs than before.<\/p>\n

Another option that\u2019s gaining in popularity is tinted glass, which comes in different shades and types. There are three main tint options: bronze, gray, and gray-green. Tinted glass works by absorbing infrared heat, rather than reflecting it, so it pulls heat into the glass itself, which then transfers it into your space slowly. The cooling effect is noticeable\u2014for example, a dark bronze tint can block up to 50% of incoming IR heat\u2014but there are trade-offs. First, tinted glass reduces visible light, so darker tints can make rooms feel dim during the day, increasing artificial light use. Second, because it absorbs heat, the glass itself gets hot, which means it can radiate heat into your space even when the sun isn\u2019t directly hitting it. We\u2019ve had customers with tinted glass on south-facing windows in hot climates complain that their windows feel warm to the touch, and that heat seeps into the room all afternoon. Tinted glass is also less effective than high-summer low-e at blocking heat, and it doesn\u2019t work well for views\u2014if you have a window overlooking a nice landscape, a dark tint can make that view murky. For that reason, we usually recommend tinted glass as a secondary option, or for specific spaces like sunrooms where you want to reduce glare without completely blocking light.<\/p>\n

Then there\u2019s reflective glass, sometimes called mirror glass, which is designed to reflect most of the sun\u2019s radiation. This type of glass has a thin metal coating (like aluminum or silver) that bounces up to 80% of incoming IR and UV radiation back away from the building. Its cooling effect is the strongest of the standard glass types, making it popular for commercial buildings in hot, sunny cities like Las Vegas or Miami. But again, there are big downsides. Reflective glass is very reflective, so it can cause glare for people inside the building and also create \u201clight pollution\u201d that affects neighboring properties\u2014we once had a retail client who had to remove their reflective glass because local residents complained about the glare reflecting into their homes. It also blocks a lot of visible light, so indoor spaces can feel dark, and it\u2019s not great for windows where you want to see out. That said, for large commercial facades where the goal is to reduce overall heat gain, it\u2019s a solid choice. We don\u2019t recommend it for residential spaces, though, because of the glare and view issues.<\/p>\n

A more modern option we\u2019ve been installing a lot lately is electrochromic or dynamic glass. This is a smart glass that can change its tint or transparency depending on the amount of sunlight, controlled by a switch or even a phone app. In summer, you can set it to tint automatically when the sun is brightest, blocking up to 90% of IR heat, and turn it clear at night to let in cool air. The cooling effect is incredible\u2014our commercial clients with dynamic glass have seen up to 35% reduction in cooling costs\u2014but it\u2019s also the most expensive option upfront. For large buildings or high-end homes, it\u2019s worth the investment, but we usually frame it as a long-term solution rather than a quick fix.<\/p>\n

Now, let\u2019s talk about what this all means for your space, because the right glass depends on your window direction. If you have west-facing windows\u2014these get direct, intense sun between 2 and 6 PM, which is the hottest part of the day\u2014high-summer low-e glass is your best bet. It blocks the peak heat without making the room dark. South-facing windows get sun all day, so a combination of high-summer low-e and a light tint (to reduce glare) works well. North-facing windows get the least direct sun, so you don\u2019t need as heavy a cooling-focused glass\u2014double-pane clear or standard low-e works just fine here. If you\u2019re in a hot, arid climate like the Southwest, you\u2019ll want a glass that prioritizes IR heat block, while in a more humid climate like the Southeast, you also want to make sure the glass blocks UV radiation (which can fade furniture) while still letting in light.<\/p>\n

I should also mention that window glass doesn\u2019t work in a vacuum\u2014pairing the right glass with proper window installation and shading (like external awnings or blinds) will give you the best cooling results. We always tell customers that upgrading their glass is one of the most impactful things they can do for summer cooling, but combining it with external shades that block sun before it hits the glass will boost those results even more.<\/p>\n

Over the years, I\u2019ve seen too many customers make the mistake of choosing the cheapest glass option without thinking about their summer cooling needs. A $200 window upgrade might seem like a good deal at first, but if it doesn\u2019t block heat, you\u2019ll end up paying hundreds more in AC bills every year. That\u2019s why our team takes the time to assess each space, look at window directions, local climate, and how you use the space, to recommend the right glass type.<\/p>\n

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Whether you\u2019re a homeowner looking to cut your summer energy bills, a small business owner wanting to keep your customers comfortable, or a property manager updating a multi-unit building, the right window glass makes a tangible difference. It\u2019s not just about feeling cooler\u2014it\u2019s about reducing your carbon footprint, cutting utility costs, and making your space usable during the hottest months. If you\u2019re ready to stop letting unnecessary heat drive up your summer cooling expenses, our team can walk you through your options, answer any questions, and help you find the best solution for your space. Reach out to our team to schedule a no-obligation assessment and start making your space more comfortable this summer.<\/p>\n

Thermal Fur<\/a> References<\/p>\n

    \n
  1. U.S. Department of Energy, \u201cWindow Glass and Energy Efficiency\u201d, Office of Energy Efficiency and Renewable Energy, 2023.<\/li>\n
  2. National Fenestration Rating Council, \u201cSolar Heat Gain Coefficient (SHGC) Ratings for Window Products\u201d, 2022.<\/li>\n
  3. American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), \u201cCooling Load Calculations for Residential Buildings\u201d, 2021.<\/li>\n
  4. International Association of Certified Home Inspectors, \u201cGuide to Window Glass Types and Performance\u201d, 2023.<\/li>\n<\/ol>\n
    \n

    INVERSIONES TONGTEX S.A.C.<\/a><\/p>\n

    Address: Building 1, Qixian Industrial Zone, Keqiao District, Shaoxing City, Zhejiang Province, China
    E-mail: Sales@tongtexpet.com
    WebSite:     https:\/\/www.tongtexpet.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    If you\u2019ve ever walked into a sun-drenched office on a 95-degree summer afternoon and felt like … What are the cooling effects of different types of window glass in summer?<\/span>Read more<\/a><\/p>\n","protected":false},"author":223,"featured_media":550,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[513],"class_list":["post-550","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-summer-cooling-4dc4-d51bbd"],"_links":{"self":[{"href":"http:\/\/www.dviason.com\/blog\/wp-json\/wp\/v2\/posts\/550","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.dviason.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.dviason.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.dviason.com\/blog\/wp-json\/wp\/v2\/users\/223"}],"replies":[{"embeddable":true,"href":"http:\/\/www.dviason.com\/blog\/wp-json\/wp\/v2\/comments?post=550"}],"version-history":[{"count":0,"href":"http:\/\/www.dviason.com\/blog\/wp-json\/wp\/v2\/posts\/550\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.dviason.com\/blog\/wp-json\/wp\/v2\/posts\/550"}],"wp:attachment":[{"href":"http:\/\/www.dviason.com\/blog\/wp-json\/wp\/v2\/media?parent=550"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.dviason.com\/blog\/wp-json\/wp\/v2\/categories?post=550"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.dviason.com\/blog\/wp-json\/wp\/v2\/tags?post=550"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}