How to Block Sunlight Heat from Windows

Published June 8, 2020

Johnny Hunt

Gardening Enthusiast

Windows are an indispensable part of your house both for aesthetics and architectural aspects. They provide natural lighting to your home during the day. However, your windows can allow more heat to warm your interior to uncomfortable levels, particularly in the summer. Cooling systems and fans can help with the problem, but they add to your monthly energy bills.

There are low-cost solutions that can save on bills and emissions and allow you to enjoy a cool and comfortable indoor environment.

Ways to Cover Your Window to Block Sun’s Heat

There are several ways you can deal with the problem of overheating in your home, and the cheaper ones entail blocking heat that comes from the sun through your windows. Some methods are easy to install, and you can do them as DIY projects or hire a professional. This article will look at some ways to block the sun’s rays through your window, so you save on energy bills.

Window Awnings

Awnings not only add style to your exterior but will help protect against the sun’s rays. When installed over the window from outside, awnings can reduce heat gain by 65 to 80% in the summer. Many people install retractable awnings often to cover the window. However, with customization, you can install canopies that shelter the entire side of the house.

The traditional materials for awnings – metal and canvas – require regular maintenance and coating ever four to six years.

Today manufacturers produce retractable awnings from various synthetic materials that have better properties and require minimal maintenance. The water-repellent acrylic and polyvinyl laminates resist mildew and do not fade quickly. Consequently, they have a prolonged lifespan. When you opt for fabric, look for characteristics that make fabric better for the purpose. For example, opaque, tightly woven block sunrays better than flimsy fabrics while light-colored materials scatter the sun’s rays more effectively than gauzy fabric.

Heat Reducing Window Film

These films can reduce up to 80 percent of heat and UV from the sun. The films are easy to apply. You can save cost if you do it yourself or you can hire a professional. With professionally installed films, you get all the relevant information about the product from the vendor; you will know how much energy the film will save and the likely payback time. The installation will cost more if you higher an expert, however, considering it will save you 25% of energy, the payback time is around 3 to 4 months – it is a worthy expenditure. The film forms airspace when applied on the inside part of the windowpane. The films block heat, and you still get to enjoy natural light. Unlike draperies, blinds, and shades, films retain the look of your window, giving you a full view (without glare) through the window. The silver films (that resemble mirror) are highly reflective and thus better than the more transparent films.

Blinds and Shades

Blinds can be installed in the interior or exterior of your house. Whichever you choose, blinds reduce heat from the sun while maintaining desired ventilation, lighting, and privacy. White or near white-colored blinds are reflective and more effective than dark-colored ones. When lowered during a sunny day, reflective blinds can reduce heat through the window by up to 45 percent.

Blackout Fabric

Blackout fabric can block sunlight by up to 100%. If you want to block sunlight and heat entirely, you should use high-quality blackout and lining fabrics. Modern manufacturers produced drapery lining that is not only cheaper but also softer in texture. These products come in the form of panels that you install behind at the back of the drapery. A downside to blackout fabric is that it blocks light. You will have to sacrifice the natural light to enjoy the saving benefits.

Blackout fabrics are therefore ideal for keeping room dark, especially bedroom windows that face the rising sun.

Curtains and Drapes

Curtains and drapes are an excellent way of blocking heat from the sun. Aside from blocking heat, they are quite useful in controlling privacy and enriching your home’s appeal. The capacity to block heat depends on the fabric that constitutes the curtain and drapes. Colored draperies can reduce the temperature by more than 33%. You can also build a cornice just above the draperies to block sunlight from entering your home.

Bubble Wrap Insulation

If you want a cheap solution to the sun’s heat, then bubble wrap insulation is your choice. The bubble wrap increases the insulation by taking advantage of the layer of still trapped air within the bubbles. For maximum efficiency, the bubble wrap must wrap tightly and seal the entire glass. However, bubble wrap is a temporary solution but can still serve the whole summer. Another downside to bubble wrap insulation is that you sacrifice the aesthetic appeal of your windows. The bubble wrap can also offer some degree (although very little) of insulation on the windows during winter. Despite the downside, bubble wrap is a quick solution if you do not want to spend much money during summer or winter.

Combining Multiple Methods

The above strategies for blocking sunlight will work to a high degree and may have one or two disadvantages. Therefore, none of them can yield ideal cooling results when used alone. For example, blackout blinds and shades will not prevent sunlight from striking the windows from outside; they reduce the rate of heat passage to your home. However, the heat that builds up from outside will eventually reach inside your home. Outdoor shades are great, but as the sun moves, the angle of the sunrays change, and at some period, you will have some heat reaching your home. Bubble wraps are cheap but offer a temporary solution that is less appealing and has poor visibility.

The best approach is to combine two or three of the above methods to get the best results.

For example, combining blinds, window films, and an outdoor shade will give excellent indoor cooling results.