Updated Nov 8, 2022
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Energy-efficient windows are specially designed to keep unwanted heat and cold air from entering or exiting your home. By maintaining the preferred thermal conditions of your home, energy-efficient windows prevent your HVAC system from overcompensating for constant shifts in temperature — ultimately saving you money on your home’s energy usage.
For whatever reason, if a total replacement isn’t feasible for you right now, there are still other ways to maximize the efficiency of your windows — no demolition required. Here are a few alternative ways to start saving on your energy bills.
Weatherstripping or a fresh caulk application are two affordable ways to ensure your windows are airtight. Either will only cost around $15 at your local hardware store and can be easily installed yourself. If you decide to use caulk to fill cracks around your window, we recommend choosing a high-quality siliconized latex product. This mix of silicone and latex is waterproof, shrink-proof, easy to apply, and has a lifespan of roughly 20 years.
If you’re not interested in modifying your windows themselves, attachable window treatments are another great way to improve the energy efficiency of your home. Interior coverings like blinds, shutters, cellular shades, and storm windows can offer temperature control and filter direct sunlight.
Similar to interior window treatments, exterior protection can offer a more subtle barrier against unwanted solar heat and promote temperature regulation. Attachable options like awnings and shutters reduce heat gain by creating shade and blocking light transmission. Other coverings like window film and solar screens are applied directly to the window itself to prevent UV infiltration and solar heat gain.
Different design types of windows operate in ways that may allow more or less air leakage, therefore impacting their overall efficiency. The most efficient window types include:
Double-hung windows are the most energy-efficient window type. They’re recognizable by their top and bottom sashes that both slide up and down. The snug fit of both frames, once they’re secure and latched, offers maximum protection against air infiltration.
Casement windows are open and closed by using a centered crank to push the window outward for ventilation. This swinging motion as opposed to a sliding window offers substantial protection against strong winds that blow toward the house. They also have a tighter seal when cranked securely to close.
More often than not, picture windows don’t open at all. They’re primarily used for statement purposes or to increase the amount of natural light in any given room. Because they don’t open, the risk of air leaks is minimal with proper installation.
Glass type or glazing is one of the most important factors to consider when it comes to the energy efficiency of a window.
The U-value (Uv) or U-factor of any glass type measures its ability to insulate. Across all window glass types, the U-value ranges between 0.20 and 1.20. For energy-efficient windows, you’ll want to look for glass marked with a U-value of 0.30 or lower. In other words, the lower the U-value, the better the insulative properties are.
Solar heat gain coefficient measures the amount of solar radiation that transmits through the window glass. Similar to the U-value of a window, the lower the SHGC rating on any glass type, the less solar heat that it allows through.
Visible transmittance describes the level of visible light transmitted through window glass. While shopping for a replacement glass type, shoot for a VT score between 0.5 and 0.7. This range will allow for natural light flow without so much infiltration that it’ll begin to heat your home.
Any window certified by ENERGY STAR is required to meet a strict set of standards set in place and backed by the U.S. Environmental Protection Agency (EPA). Therefore, a window with an ENERGY STAR sticker is indicative of proven energy efficiency. ENERGY STAR’s criteria for a qualifiable energy-efficient window include:
The National Fenestration Rating Council (NFRC) is a non-profit organization dedicated to independent testing and certifying the energy efficiency of household windows, doors, and skylights. Energy performance labels from the NFRC provided valuable information regarding the energy efficiency of a window including:
You can invest in the most top-of-the-line energy-efficient windows, but if the installation is poor, you won’t get the proper return on investment. If anything, you’ll spend even more money on correcting the fitting. Superior performance from your energy-efficient windows requires an airtight seal, which is only guaranteed by hiring a licensed and qualified installation team for the job.
Unless you or the person attempting the DIY approach have extensive prior experience in window installations, we highly suggest hiring a professional to do the job. Most professional installation services also come with warranty coverage. Opting to install energy-efficient windows yourself cheats you out of any long-term coverage for your windows as well.
The placement of the windows within your home, as well as the overall orientation of the house itself, will have some role in the total efficiency. Houses located in regions with cooler seasonal climates should prioritize orienting their windows toward the east and south. Likewise, homes with warmer seasons should orient their windows toward the north and west. Improper window installation can ultimately be more taxing on your home’s energy efficiency.
On average, energy-efficient windows will cost anywhere from $300 to $1,000 per window. Though energy-efficient windows can be a bit of an expensive upfront investment, long-term savings are lucrative. According to the United States Department of Energy, energy-efficient windows can save the average homeowner between $100 and $500 per year in energy expenses.
Based on ENERGY STAR’s own savings projections, installing energy-efficient certified windows, doors, or even skylights can reduce residential energy bills by an average of 12% next to non-certified products. After just one year of living with energy-efficient windows rather than traditional single-pane frames, a standard household reduces its carbon footprint by 1,006 to 6,205 pounds of CO₂.
Energy-efficient windows are worth the initial investment for most home types. Not only do they offer the opportunity to save big on recurring utility bills, but they also play an impressive role in reducing your home’s carbon output. Still, the true return on investment in energy-efficient windows will depend on your home’s current energy consumption rates. We recommend having a home energy audit done to assess how each area of your house contributes to your overall energy consumption.
Any window certified by ENERGY STAR is going to be the most energy efficient option available. In terms of window type, fixed styles like picture windows offer maximum protection against air leakage due to their lack of ventilation.
A window’s energy efficiency is primarily defined by its ability to buffer the impact of inward airflow, sunlight, and solar energy on the interior temperature of a home.
Energy-efficient windows tend to cost more at first than traditional window types. Part of that upfront cost is installation. While we strongly recommend that any window installation, energy-efficient or not, be handled by a professional, high-quality installation is especially important for energy-saving.
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