Did you know that up to 30% of your home heating energy gets lost through your windows? This means your windows waste almost a third of the energy you pay for with your hard-earned money! This also means that they make your home either too cold or too hot, depending on the season.
As a result, you may have found yourself setting your HVAC system on full blast. This, in turn, further raises your heating and cooling costs.
For those reasons, consider investing in energy saving windows.
Before you shell out money for new windows, though, it’s best you know how to spot the real energy savers first. Don’t worry, as we’ve created this comprehensive guide on choosing energy-efficient windows. Read on to discover what exactly you should look for when buying new or replacement windows.
Go With Energy Star Certified Windows
Energy Star windows can help reduce your home’s energy consumption by about 12%. This makes Energy Star windows the most energy-efficient option in the market. At the very least, they boast high-quality materials, solid construction, and multi-glazing.
Do note that only windows certified by the Department of Energy can carry the Energy Star logo. These windows have undergone rigorous testing and quality control procedures. They also come with at least a 10-year manufacturer’s warranty.
Invest in NFRC Certified Windows
NFRC stands for “National Fenestration Rating Council.” This non-profit organization created the most common window energy rating system used today. The NFRC rating is the system used by none other than Energy Star.
So, whenever you see the Energy Star logo on a window, expect the NFRC label on it, too. You’ll often see up to five different energy criteria on the NFRC label.
We’ll break down each factor below to help you choose among your many options.
U-Factor
U-factor, also known as U-value, gauges a window’s ability to insulate. It’s a measurement of how much heat flow the window can resist. In most cases, you’ll see U-factors range from as low as 0.15 to as high as 1.3.
The higher the U-value is, the lower the window’s ability to resist heat loss. So, a window with a 1.3 U-factor is less insulating than one with a 0.2 rating. The window with the higher value also allows more heat to escape from inside the building.
If you live in a cold climate, the most energy-efficient windows are those with the lowest U-factor. This is especially true for north- and south-facing windows, which receive a lot of solar heat. If you live in a warmer climate, a U-value rating of at least 0.3 can suffice.
Solar Heat Gain Coefficient (SHGC)
In windows, SHGC measures how much solar radiation a window admits. It factors in both direct and indirect solar radiation transmission in windows. It also accounts for the amount of solar heat a window absorbs and then releases as heat into a home.
SHGC ratings can range from 0 to 1. Like the U-value, the lower the SHGC is, the better the window is when it comes to helping control heat. By contrast, the higher the SHGC is, the more heat the window permits to enter a building.
With that said, if you live in a warm climate, you’d want to invest in home windows with a low SHGC. This applies to all your windows, whichever direction they face. However, you should also beef up your south-facing windows with extra shading.
If you live in a cold climate, you’d want your north-, east-, and west-facing windows to have low SHGC values, too. As for your south-facing windows, go for those with an SHGC rating paired with a low U-value. You want a high SHGC so that your windows can allow natural heat to penetrate your home.
Visible Transmittance (VT)
VT in windows refers to how much visible sunlight the glass allows to penetrate. It’s the amount of sunlight the window transmits through its glazed layers. The higher the VT rating of a window is, the more visible light it permits to enter.
Like SHGC, VT ratings also range from 0 to 1. However, the exact rating you need depends on your preference or lighting needs.
Suppose you want to use as much natural light as possible to reduce your need for artificial light. In this case, you should go for products with a higher VT. They’ll let you harness sunlight so that you can cut your lighting costs.
However, it would be better to stick to a lower VT rating if you want to minimize interior glare. Applying window tinting films can also help control glare-related issues.
Air Leakage
Air leakage refers to how much air moves around a window. You’ll find this measured in cubic feet per minute per square foot of frame area (cfm/ft2). The lower the rating is, the “tighter” the window is, so the fewer air leaks it also experiences.
However, the actual window installation process also influences air leakage. Improper placement defeats the purpose of investing in high-quality, energy-efficient windows. As such, it’s best to hire a contractor for your window replacement or new installation needs.
Condensation Resistance (CR)
Granted, the NFRC considers condensation resistance as an optional rating. However, it’s still a good idea to invest in windows with a high CR rating, especially if you live in a humid area. That’s because this rating measures how well a window resists condensation.
Keep in mind that excessive condensation on windows can give rise to dampness issues. For example, all those water droplets can drip down the window’s wood frame. This can then contribute to the frame’s early decay.
Moreover, indoor condensation can lead to increased dampness at home. If this happens, your home may be at risk of mold growth, which can proliferate in just 24 to 48 hours. From there, existing molds can release more spores into the air and trigger even more molds to grow.
It’s in this way that condensation can also have an indirect impact on your home’s HVAC system. The more mold spores in your indoor air, the more residue can form on your comfort equipment. They can also cause your air filters to get all clogged up way sooner than normal.
Clogged filters and residue build-up force HVAC systems to work harder. This, in turn, contributes to more energy used by comfort systems. By contrast, HVAC units without airflow problems can trim energy costs by at least 10%.
So, whether you’re installing new windows or replacing old ones, be sure to factor in the CR rating, too. Besides, you wouldn’t want your windows to always be foggy, would you? That would make it difficult for you to enjoy the view and even add to your home maintenance duties.
Go With More Layers
Multi-glazed or -paned windows are now in about six in 10 US homes. These multi-layered options include double- and triple-glazed windows. Their multiple layers make them more energy-efficient than their single-pane counterparts.
Double-glazed windows have two glass layers that then create a sealed space in the middle. The center section usually then gets filled with an insulating gas, like argon.
Triple-paned windows are pretty much the same, except they come with three layers of glass. These layers create two separate sections that get loaded with insulating gas, too. This construction makes triple-glazing better in insulating than double- or single-glazing.
However, it’s also because of these benefits that triple-paned windows are expensive. So, if your budget won’t cut it, don’t worry, as double-paned windows can still suffice.
Consider Adding Energy Saving Window Treatments
Window awnings can block anywhere from 65% to 77% of solar heat gains. So long as placed strategically, they can help make your windows even more efficient. More than that, their shading properties help keep your home comfortable and cool.
If you go with retractable awnings, you can choose when exactly to shade your windows. In this way, you have the freedom to retract the awnings when you want to use pure sunlight. When things are heating up, you can then extend the awnings to help shade your windows.
Window films can also help reduce solar heat gains while protecting you from UV exposure. Before you install them, though, make sure you check the warranty terms of your new windows first. Some manufacturers void warranties if you apply films on their windows.
Keep Your Home Cozy With Energy Saving Windows
There you have it, your ultimate guide on how to choose energy saving windows. The easiest way is to always look for the Energy Star logo and the NFRC label. If these two are present, you can be sure those windows are energy-efficient.
Just don’t forget to consider climate-related factors and your windows’ orientation too.
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