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Will Low-E Windows Affect The Growth Of My House Plants?

March 28th, 2023 | 8 min. read

Will Low-E Windows Affect The Growth Of My House Plants?

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As a plant parent, you care deeply for your foliage. You work hard to ensure they have enough water, nutrients, and, most importantly, sunlight. 

Whether you’re considering replacing your home’s windows with something more energy efficient or have recently noticed your windows have been affecting your plants’ growth, the last thing you want is to make a change that will harm your herbage. 

Are my windows providing enough sunlight? If I upgrade to Low-E windows, will it affect my plants' growth? How do I know my plants are getting what they need? 

These are just a few questions that concern you when considering energy-efficient windows and your house plants. 

At Southwest Exteriors, we’ve helped thousands of homeowners transform and improve the energy efficiency of their homes since 1989. 

When investing in a window replacement, we want to address all your concerns and provide you with all the information you need to feel confident your project will meet your needs. 

So, will new windows affect the way your plants grow? Let’s look into it. 


Energy-Efficient Windows: Will They Affect House Plant Growth? 

If you just replaced your windows or are considering starting the project soon, you want to know if specific energy-efficient qualities will affect your house plants in any way. 

To understand what makes a window energy efficient and how it affects your home, let’s break down window energy ratings, what they do, and how they affect your home and plants. 


4 Key Window Energy Ratings That Affect Light In Your Home

Energy-efficient windows provide maximum protection against harmful UV and infrared rays, drafts, and insulate your home.

The largest factor that affects the energy efficiency of your windows is the glass. With the glass, there are four common energy ratings to understand. 


UV Percentage 

This measures the percentage of UV rays that penetrate through the window. The lower the UV percentage, the more UV rays come through, making your house warmer. UV rays are classified into three categories: UV-A, UV-B, and UV-C. 

According to the International Ultraviolet Association, “normal glass (as used in windows) is transparent to UV radiation to a wavelength of about 330 nanometers (nm) (UV-A),” allowing almost 100% of UV-A rays through the window. Below 330 nm will block UV-B and UV-C rays, which are more harmful.

How Does UV Percentage Affect My Home? 

The UV percentage of a window affects how many UV rays penetrate through your window glass and into your home. The more UV rays, the hotter your home becomes. 

Will UV Percentage Affect My Plants? 

Because UV percentage works to block heat and not light, it should not affect the growth of your plants. It will help make your home feel cooler in the summer and provide a more stable climate for your plants. 


Infrared Percentage

This is the percentage of infrared rays that penetrate through a window. Britannica defines infrared rays to be the “portion of the electromagnetic spectrum that extends from the long wavelength, or red, end of the visible-light range to the microwave range.” 

These light rays are invisible to the eye but produce heat just like any other ray on the electromagnetic spectrum. 

How Does Infrared Percentage Affect My Home? 

Similarly to UV rays, infrared rays increase the overall temperature of your home when they come through your window glass. These rays are incredibly harmful and can damage your furniture, carpet, and even your skin. 

The fewer infrared rays in your home, the cooler your home will feel in front of a window, and the better your home is protected. 

Will Infrared Percentage Affect My Plants? 

Also, like UV rays, infrared rays affect heat, not light. The infrared percentage will not affect how much light reaches your plants. It can help block harmful rays that cause sunburn to your plants

So, if you’ve noticed your window plants have brown spots on their leaves, energy-efficient windows that block most infrared rays will be helpful. 


Solar Heat Gain Coefficient (SHGC)

This measures the amount of solar heat that comes through a window, ranging from 0 – 1. The U.S. Department of Energy’s consumer resource, Energy Saver, says the lower the SHGC, the less heat from the sun comes through a window, helping your home to stay cool during a hot summer (and fall and spring if you’re in Texas).

With a low SHGC, you will also not get as much heat radiating from your windows as you would with normal glass.

How Does SHGC Affect My Home? 

The SHGC affects how much heat the window glass can transfer from the outside to the inside. A low SHGC helps your home stay cooler. 

Will SHGC Affect My Plants? 

The SHGC of your windows will not affect the amount of sunlight your plants get. This energy rating is another measurement of heat, not light. 


Visible Transmittance 

Visible transmittance (VT) refers to the amount of visible light that penetrates through the window. This can be affected by glass glazings and tints. VT is measured from 0-1.

The higher the number, the more visible light will shine into your home.

Visible transmittance is most popularly measured in replacement windows that have special coatings, like Low-E coatings or tinted coatings. 

How Does Visible Transmittance Affect My Home? 

The VT of a window tells you how much sunlight will transmit through your window. If you want maximum sunlight coming through your windows, then you want a window with a high VT rating. 

Will Visible Transmittance Affect My Plants? 

This energy measurement is the largest factor to look at to determine if your windows will affect your plant's growth because it deals directly with sunlight. 

If you choose a window with a low VT, less sunlight will come into your home. This can directly affect your house plants, how much sunlight they get, and how well they grow. 

To ensure your plants receive enough sunlight, choose a replacement window with a higher VT rating. If you want windows with a lower VT to block more sunlight in a specific room or side of your home, consider moving your indoor plants to a different location where the amount of sunlight they receive is not affected. 


Do Energy-Efficient Windows Affect House Plant Growth? The Answer: Maybe

Now you understand four of the most common window energy ratings, how they affect your home, and how they may affect your plants. 

Overall, most energy-efficient windows should not affect the growth of your house plants. 

If you are concerned about your new windows harming the growth of your plants, pay attention to the visible transmittance rating. The lower the VT, the less sunlight your plants will get, potentially affecting their growth in a negative way. 

A window with a lower infrared percentage can also help protect your plants from potential sunburn without compromising the amount of sunlight they receive. 

Other energy-efficient factors, like the UV percentage and SHGC, affect the amount of heat that penetrates through your windows. These ratings will help make your home more energy efficient without harming your plants.  

As a window replacement contractor for over 33 years, Southwest Exteriors is here to educate you and address all your concerns about your window replacement project. 

We want to provide you with all the information you need to feel comfortable and confident in your new windows and feel assured they will help your home, not harm it. 

Before investing in new windows, it’s important you understand what makes a window energy-efficient and how energy ratings affect your home. 

This article will outline seven common window energy ratings, how they affect your windows, and what it means for your home. Then, you can choose the best replacement windows that will meet your (and your plants) needs for energy efficiency and performance.