Windows and Home Energy Efficiency: A Quick Guide

Energy-efficient living spaces are now the standard for most homeowners. When they invest in home improvement projects, they don’t just focus on aesthetics and long-term performance anymore. Now, they also take into account how much energy they’ll be able to save with a particular investment, such as window replacement.

The Relationship Between Windows and Efficiency

Your home’s energy efficiency is directly tied to your windows. These essential components help keep a pleasant indoor temperature, which in turn, allows for more energy savings. If your windows are already old and worn, they might compromise the look and feel of your home. Almost 25% of your home’s energy loss, in fact, is due to failing units. That’s an alarmingly large amount of money out of your window!

To detail, the average electricity consumption in an American home is about 901 kWh monthly, and 10,812 kWh annually. Louisiana is the U.S state with the highest annual energy usage rate at 15, 435 kWh per residential customer. This is a huge contrast to Hawaii, with a consumption of only 6,166 kWh per residential customer yearly. If you want to save more energy in your home, this shows you that it pays to replace your failing units with newer, more energy-efficient windows.

What Makes an Energy-Efficient Window?

The framing material and glass package your replacement window use can affect its energy performance. There are a variety of options available in today’s market, such as vinyl, fiberglass, aluminum, and wood. Each come with their pros and cons, but if you want something better, you should consider windows with composite frames. Composite windows offer some of the best features of other framing materials, like wood’s durability and insulating value or vinyl’s low maintenance requirement. Because they don’t warp, corrode, or crack, these windows keep more airtight seals. When augmented with low-emissivity (low-E) glass, they can more effectively keep indoor heat in and outdoor heat out.

This results in:

  • Higher Levels of Comfort. By blocking outdoor air from infiltrating your home, energy-efficient windows help keep your home thermally comfortable. This means you can enjoy warmer rooms during winter and cooler living spaces in summer without relying too much on your HVAC system.
  • Increased Access to Natural Light. Low-E glass is specially handy for this, letting in sunlight without the heat that accompanies it. You can experience a brighter, roomier feel in your home while still keeping a pleasant indoor environment.
  • Reduced Interior Fading. Energy-efficient windows can also keep your interiors intact as low-E glass also blocks UV light, protecting your walls, flooring, and furniture from sun damage.
  • More Energy Savings. With the abovementioned benefits provided by energy-efficient windows, you’ll see a marked decrease on your energy bill down the line.

Energy Efficiency Vs. Energy Conservation

Energy efficiency and energy conservation are two common words you’ll hear in anything related to energy savings. The two may sound similar but are entirely different things. For starters, energy efficiency involves the use of technology which calls for less energy while carrying out the same function. For instance, opting for compact fluorescent bulbs instead of incandescent lighting. The former uses less energy than the latter but produces the same amount of light. Energy conservation, on the other hand, refers to any method that leads to lower energy usage, like turning off lights when not in use.

The NFRC Label

Energy-efficient windows are measured through certain factors by the National Fenestration Rating Council (NFRC). This non-profit organization details a window’s energy performance ratings, which you’ll see included on the NFRC label. These particular categories include:

  • U-Factor. The measure of how well a window keeps indoor heat from escaping. A lower rating means a more energy-efficient window.
  • Solar Heat Gain Coefficient. The measure of how well a window can resist unwanted heat gain. The lower the rating, the better, especially in warmer climates. This means your replacement window can help keep your home cool and comfortable by keeping passive heating at bay.
  • Visible Transmittance. The measure of how well a window effectively lets natural light through, the higher the visible transmittance rating, the more visible light enters your home. The ideal rating for your home will depend on your daylighting requirements, or if you need to reduce interior glare in a space.
  • Air Leakage. The measure of how much air a window lets through when closed. A lower rating means better insulating action, preventing outdoor air from compromising thermal stability and leading to energy loss.

Finding Energy-Efficient Windows

One easy way to determine a window’s’ energy performance is to look for the ENERGY STAR label on them. ENERGY STAR was established by the U.S. Environmental Protection Agency as a voluntary labeling program to identify energy-efficient products, meaning a label on a product means they have undergone testing and met stringent energy performance requirements. An ENERGY STAR label is a quick way to help homeowners make more informed purchasing decisions about their window replacements.

ENERGY STAR is the universal sign of energy efficiency, after all. Since its inception in 1992, the program has reduced up to 2.5 billion tons of greenhouse gas. It has also helped save up to $362 billion on utility bills. When you choose an ENERGY STAR qualified window, you know you’re choosing energy efficiency.

When it comes to home upgrades, always keep energy efficiency in mind. To ensure an investment like window replacement delivers superior energy performance, it pays to hire a premier window company to do the job for you. A replacement window is only as good (or in this case, as energy-efficient) as its installer, after all.

Author Bio:

Alex Esler is a marketing manager for Renewal by Andersen, the window replacement subsidiary of Andersen Corporation. Their local, family-owned offices in Southern New England, Greater Philadelphia and Colorado make up the largest replacement window company in a network of 100 Renewal by Andersen dealers. Committed to providing high-quality window and door solutions, she shares information and tips through the company blog. Check it out for updates from Alex!

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