Window Film Blog

Does Window Film Reduce Heat in Your House?

If you’re a homeowner in the United States, you’re probably familiar with the challenges of managing indoor temperature and energy costs. With the ever-increasing utility bills and the desire for a comfortable living space, it’s crucial to explore options that can help you maintain a cool and energy-efficient home. One solution that’s gaining popularity is residential window film. But the burning question is: Does window film reduce heat in your house?

At Concord Window Film, we understand your concerns and are here to provide you with the answers you need. Let’s delve into the science behind window film and its impact on your home’s temperature.

Understanding Solar Heat Gain

Before we discuss the benefits of window film, it’s important to understand the concept of solar heat gain. Solar heat gain refers to the increase in indoor temperature caused by sunlight passing through your windows. The more sunlight that enters your home, the warmer it gets. This can lead to discomfort and increased cooling costs, especially during the scorching summer months.

The U.S. Department of Energy estimates that up to 30% of energy used for HVAC in a home is lost through windows. And the Energy Information Agency reports the average US home spends 12% on air conditioning alone – ballooning to 27% in warm, humid areas like Florida and the Gulf States.

Learn more about solar heat gain and how it is measured by the solar heat gain coefficient.

How Window Film Reduces Heat in Your House

Solar control window films are designed to combat the effects of solar heat gain. They work by reflecting, absorbing, and dissipating solar energy before it can penetrate your windows. Different window films use different technologies to block the heat: dyes, metals, or nano-particles like ceramics. (Check out our overview of window film technologies over time.) Below is an illustration of a 1/8” piece of clear glass and the same glass with Concord Window Film’s ComforTech™ Ceramic Series 35 film to demonstrate how window film works to block solar heat:

How Does Window Film Work -

The amount of solar heat that each film blocks is measured by the total solar energy rejected or TSER. All reputable window films are rated by the National Fenestration Rating Council (NFRC) and provide their performance specifications – it’s the only way to know what you are buying and compare across brands. The NFRC measures the TSER of films – which is a measurement of the total solar energy that the film and glass in concert reject.

Below are the performance specs for ComforTech™ Ceramic Series. You can see that TSER increases as the film gets darker with our darkest shade, ComforTech™ 05 having a TSER of 82%:

ComforTech Window Film Specifications Chart

Read more about total solar energy rejected or TSER.

The Benefits of Using Window Film

Now that we’ve explored how window film works, let’s discuss the advantages it offers:

Improved Comfort

By reducing heat, window film helps create a more comfortable living environment. You’ll experience fewer temperature fluctuations and won’t need to rely as heavily on your air conditioning.

Energy Efficiency

Less heat entering your home means your cooling system doesn’t have to work as hard, leading to potential energy savings. In fact, the U.S. DOE classifies window film as an “energy efficient window covering”. It also says window film can decrease your utility bill by 5-15% annually depending on where you live.

UV Protection

Many window films also block harmful UV rays, which can damage your furnishings and flooring over time. This protection extends the life of your interior decor. All ComforTech™ shades block 99% of UV light measured in the 300-380nm spectrum.


Reflective and privacy window films provide an added layer of privacy during the day without compromising natural light. ComforTech™ 25, 15 and 05 are all considered privacy films in addition to the solar control benefits they offer.


So, does window film reduce heat in your house? Absolutely. The right window film can significantly reduce solar heat gain, leading to a more comfortable and energy-efficient home. If you’re ready to take control of your indoor temperature and utility bills, explore our selection of ComforTech™ Ceramic Series solar control window films at

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