Energy Star Windows: An Overview
Improve Energy Efficiency and Save Money for Decades to Come!
Energy Star certified windows help homeowners reduce their energy costs for keeping their home cool throughout the hot Florida weather. Discover what you need to know about Energy Star and what it means for your home’s energy efficiency.
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What Is Energy Star?
ENERGY STAR is a government-backed program promoting energy efficiency for homes and businesses. It’s administered by the U.S. Environmental Protection Agency (EPA) with the goal of delivering energy efficiency-enhancing solutions for businesses and private households alike. The blue label is often used as a means of identifying products that meet strong energy efficiency standards.
Energy Savings Calculator
Discover Your Potential Annual Energy Savings
Adjust the slider below to match what your current monthly electricity bill is to see an estimate of your potential annual savings*:
*Based on figures determined by ENERGY STAR when upgrading from a single-pane ‘clear’ window to an ENERGY STAR compliant window at an average 12% energy consumption reduction.
Things to Know About ENERGY STAR Windows
Florida’s Climate Zone
When it comes to energy efficiency, different climate zones may make a window more or less energy efficient. For example, Florida is in a Southern climate zone per ENERGY STAR certifications.
U-Factor
U-factor is a key metric used by the ENERGY STAR program to determine a window’s insulation. For Southern climate zones, the program recommends windows have a U-factor rating under 0.32.
SHGC
SHGC, or Solar Heat Gain Coefficient, is a measure of how much of the sun’s heat gets through a window. ENERGY Star windows must have an SHGC of 0.23 or lower to qualify as compliant.
Federal Tax Credits
To qualify for federal tax credits under ENERGY STAR, a window must have a U-factor of less than 0.22 and an SHGC under 0.21. A window can be ENERGY STAR certified without being eligible.
Air Leakage Requirement
To pass ENERGY STAR certification, a window must have an air leakage rate equal to or less than 0.3 cfm/sq. ft. (cubic feet per minute per square foot of window). This is because air leakage transmits warmth.
NFRC Testing
To earn ENERGY STAR certified status, a window must first be inspected by an independent body such as the National Fenestration Rating Council (NFRC) to verify its energy efficiency characteristics.
The Best Brands for Your Energy-Efficient Windows
Karoly Windows partners with the best window manufacturers in Florida to bring you reliable energy efficient windows that not only save you money, but will last you a proverbial lifetime. We’re picky about the windows we install because we want you to have the best possible windows for your home!
That’s why we work with Simonton and PGT. They’re the best two manufacturers of ENERGY STAR v7.0-compliant windows in Florida! Simonton has the best window warranty in the business and stands behind their products strongly because they’re so high-quality. PGT, meanwhile, obsessively tests their windows to verify their energy efficiency, impact resistance, and more so you can get windows that you know are reliable.
ENERGY STAR Window Options
Impact Windows
Double Hung Windows
Sliding Windows
Picture Windows
Casement Windows
Awning Windows
Bay Windows
Custom Windows
Secure Financing to Get the Best Replacement Windows!
Installing new windows can be a costly endeavor, which can force homeowners to put off getting their windows until after it’s too late or miss out on potential energy savings for months or even years. This is where window financing can help.
One of the things that every good window replacement company offers is a multitude of financing options to help make it easier for homeowners to get their new windows installed sooner so they can protect their homes and start saving on their electricity bills.
Karoly Windows & Doors works with financial institutions like GreenSky and Synchrony Financial to provide flexible financing options for window installation. Choose from a variety of financing options, including some that have ‘no payments required’ periods where you can avoid paying any interest if you pay off the loan before the ‘no payment required’ period ends.
0% Interest Financing Options
Two great plans — see which one fits your budget best.
GreenSky 12-Month Plan
- No payments required for 12 months
- Pay it off within 12 months = 0% interest
- $0 Down Payment
- If paying after 12 months → fixed payments over 84 months
Synchrony 24-Month Plan
- Lower monthly payments starting right away
- Pay it off within 24 months = 0% interest
- $0 Down Payment
- Minimum payment ≈ 3% of balance each month
See Your Actual Monthly Numbers
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Get Energy Efficient Doors for Your Home!
Windows aren’t the only kind of fenestration that need to be energy-efficient! The doors to your home are another point where outside heat can get in or your cooled air can leak out. So, be sure to complete the energy efficiency upgrade of your home with ENERGY STAR doors!
ENERGY STAR Door Options
Sliding Glass Doors
Standard Sliding Patio Doors
Pocket Sliding Doors
Enjoy convenience and energy efficiency at the same time with doors that have extended rails along the wall of your home! Get yours from a trusted installer.
Bi-Parting Doors
Add elegance and energy efficiency with bi-parting sliding glass doors for your home. These doors open and close from the center to keep your home cool.
Exterior Doors
Choose from a wide variety of made-to-order custom exterior doors in different styles to fit your home’s unique aesthetic while preserving energy efficiency.
Entry Doors
Double Entry Doors
To make your double doors maximally energy-efficient, you need installation that’s twice as precise to prevent gaps and other issues. Precision that Karoly specializes in.
French Doors
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Maximize Safety AND Energy Efficiency
Every ENERGY STAR-rated window and door Karoly Windows & Doors installs is an impact-resistant product. Why? There are several reasons.
First, and foremost, it’s because Karoly is dedicated to the safety and wellbeing of our customers. We want you to have the best fenestration (i.e., windows and doors) to protect your family and your property from not only high energy bills, but from the dangers of Florida’s severe weather.
It also helps to ensure that your windows and doors meet Florida Building Code (FBC) standards. The FBC specifies the use of impact-rated windows and doors for residential homes in Florida because much of the state faces heightened risk of damage from hurricanes. Failure to meet FBC guidelines can result in stop work orders, fines, and other penalties.
By using impact windows, you can help ensure that your installation will avoid regulatory complications.
ENERGY STAR Windows FAQs
Are ENERGY STAR Windows Worth It?
Purchasing windows that have earned ENERGY STAR certification may be initially more costly than getting basic windows that lack energy efficiency-enhancing features like low-e glass, improved insulation, argon gas fill, and extra layers of glass.
However, the cost over time of the “cheaper” window may be higher in the long run.
ENERGY STAR certified windows provide a consistent long-term savings on energy bills since your home’s climate control system doesn’t have to work quite as hard, saving electricity for your home.
Additionally, because there’s less air leakage with an ENERGY STAR window, you can enjoy enhanced comfort in your home with fewer drafts and less air infiltration.
According to data from an ENERGY STAR estimate, the average homeowner in Jacksonville, FL can save around $536 a year if they replace their clear, single-pane glass windows with ENERGY STAR-compliant windows. However, that’s just an average based on a $0.15 electricity billing rate.
The more energy your home uses to maintain a comfortable temperature, the bigger the savings you can realize for putting in ENERGY STAR v7.0-compliant windows. So, if your home typically needs more energy to keep cool in summer and warm in winter, you stand to save even more money each year by replacing your windows.
In addition to the monetary savings, adding ENERGY STAR windows to your home helps reduce your carbon footprint. This makes them an ideal upgrade for any homeowner who wants to be more environmentally-conscious.
What Are the Energy Efficiency Metrics I Should Know?
When assessing a window’s energy efficiency, there are three key metrics to know—ones that appear on NFRC labels for windows. These three energy-efficiency specific metrics are:
- U-Factor. A measurement quantifying how well the window insulates your home from thermal transfer. The lower the number, the less energy moves between your home and the outside.
- Solar Heat Gain Coefficient (SHGC). A measurement of how much of the sun’s heat gets through the window. The higher the number, the more heat from the sun gets through.
- Air Leakage. A measurement of how much air can enter or leave a room through the window, expressed as cubic feet per minute. This helps improve energy efficiency by preventing heat gain or loss from air entering or escaping your home.
Knowing these three energy metrics can help you identify windows that are ENERGY STAR compliant. They’ll be prominently displayed on the NFRC sticker for the window.
What Is an ENERGY STAR Window?
An ENERGY STAR window is a window that has been certified to meet certain energy performance standards set by the EPA, which are independently tested by the NFRC.
These windows help homeowners reduce their energy consumption for their home’s climate control systems, leading to reduced energy bills and a greener environment.
What are the standards a window needs to meet to be ENERGY STAR v7.0 compliant? The answer actually changes from one “climate zone” to the next.
In northern climate zones, a window would need to have a u factor of 0.22 or less and an SHGC of 0.17 or more to be considered ENERGY STAR certified. However, here in Florida, which is in the Southern climate zone, the u-factor of a window has to be 0.32 or less and the SHGC has to be 0.23 or less.
Why is there a difference between requiring low SHGC in Florida vs higher SHGC in Northern climates? Because, in Florida, the goal for the majority of the year is to keep your home cool. Meanwhile, in northern climates, the goal is to keep the home warmer.
Higher Solar Heat Gain Coefficient values allow more of the sun’s heat inside the home. That’s desirable in the north, but bad in the south where temperatures run high and your air conditioner has to work overtime year-round.
Do ENERGY STAR Windows Qualify for Tax Credits?
ENERGY STAR certified windows can qualify for environmental tax credits IF they meet the “ENERGY STAR Most Efficient” criteria for the climate zone you’re installing your windows in.
If you go to the NFRC’s Certified Product Directory (CPD) search page and find your window on it using the CPD number, check to see if the window has a green shade for your climate area. If it does, it may qualify for “energy efficient home improvement” tax credits.
These tax credits for the 2025 fiscal year can be worth up to $3,200 off your federal income taxes.
However, it is important to note that windows will only count for a part of that maximum tax credit. According to the IRS website, windows can earn up to $600 total tax credits. To get the maximum tax credit, you’ll need to make broader improvements to your home’s energy efficiency. For example, energy efficient doors can earn a tax credit of $250 per door (up to $500 total), and adding new insulation can earn up to $1,200 in tax credits (which also helps ensure you get the biggest energy savings for your home).
What Are the Climate Zones Per ENERGY STAR?
ENERGY STAR separates the USA into four distinct Climate Zones:
- Northern
- North-Central
- South-Central
- Southern
Florida is wholly within the “Southern” region of the ENERGY STAR Climate Zone Map. We’re one of only two states to fall completely within this zone (the other being Hawaii).
So, when checking the ENERGY STAR certification for windows, make sure that they’re certified for the Southern Climate Zone.
Does Installation Affect My Window’s Energy Efficiency?
Yes! The quality of your new window installation can absolutely affect the energy efficiency of your new window.
A window can have all of the best insulation and energy efficiency features on the market, but if there’s a gap around the window frame, it will leak air between your home and the outside.
A high-quality window installation where the installer ensures that there is no gap around the window, adds insulation to the area around the window frame, and ensures that the new window is seated properly in the opening creates a tight seal that better protects your home and makes the most of the energy efficiency features of your window.
This is why it’s important to work with installers who know what they’re doing and are dedicated to doing things the right way.
Can a Single Window Meet ENERGY STAR Requirements in Every State of the USA?
What makes a window energy-efficient in a northern state may actually make it less energy efficient in a southern state like Florida. However, there are some window products on the market that are universally ENERGY STAR certified in all 50 states of the USA. So, the answer is “Yes, but it’s not likely to meet the ‘Most Energy Efficient’ requirements for tax credits.”
As noted by the ENERGY STAR FAQ page: “A window with a U-factor of less than or equal to 0.27 and a Solar Heat Gain Coefficient (SHGC) of less than or equal to 0.25 could earn the ENERGY STAR in all climate regions.”
However, to get the biggest energy efficiency benefits in Florida, you’ll want to get a window that is tailored for energy efficiency in southern climate zones.
Will Low-E Glass Meet ENERGY STAR Requirements?
Energy Star v7.0 has some strict requirements for windows, doors, and skylights. Using low-e glass in your window or door can help it meet these requirements, but that alone doesn’t guarantee compliance.
When buying new windows and doors, look at the U-Factor and Solar Heat Gain Coefficient (SHGC) figures for that product to see if they meet the program’s requirements.
For windows in the southern U.S. to meet Energy Star v7.0 standards, they must have a U-factor of 0.32 or less and an SHGC of 0.23 or less. Door requirements would be 0.50 or lower U-factor and 0.25 or less SHGC.
Look for the ENERGY STAR mark on the product and verify it through the Energy Star product finder page.
Are Impact Windows More Energy Efficient?
When variables such as coatings and frame materials are the same, impact windows do tend to be more energy efficient compared to single-pane non-impact windows.
This is because of how impact windows tend to be constructed. Impact windows typically include multiple layers of glass, air gaps (sometimes filled with inert gases) to inhibit heat transfer between the home and the outside, laminate interlayers, and heavier construction.
These features tend to make impact windows more energy efficient than similar non-impact windows.
For example, if you look at ENERGY STAR’s energy efficiency savings chart for clear glass windows, you can see how much money the average homeowner could save by changing from single pane clear glass windows or double pane clear glass windows to an ENERGY STAR certified window. In all cases, the cost savings going from a single pane clear glass window to an ENERGY STAR window was larger than going from a double pane window to the ENERGY STAR window (though the ENERGY STAR window still provided a significant savings over the double pane clear window).
In the Southern Climate zone, switching from single pane to ENERGY STAR windows saves an average of $563/year, while switching from double pane clear glass windows saves $373/year. In other words, the double pane window was already about $190 more energy-efficient than the single-pane windows.
Merely having two panes of glass provides a significant energy savings that can be quantified with hard numbers!
Get Your ENERGY STAR Windows from Karoly!
So, why should you get your new energy-efficient windows and doors from Karoly? It’s because Karoly Windows:
Has 20+ Years of Experience. We’ve worked with homeowners throughout the greater Tampa Bay area for over 20 years, earning accolades and positive reviews for our dedication to quality and service.
Isn’t Beholden to a Single Manufacturer. We work with multiple window and door manufacturers so we can get the best deals on new windows and doors for your needs.
Does the Work the Right Way Every Time. Our installation techs are all in-house employees who are held to our company’s high standards. With Karoly, you never have to worry about an unskilled third-party contractor doing the job incorrectly. You get experienced techs who are on the Karoly payroll.
Specializes in Florida Residential Windows. We’re a locally-owned Florida-based business that specializes in windows and doors made for the Floridian market. We know the Florida Building Code and how to uphold it so you can trust your new windows to last.
Offers a Platinum Standard Lifetime Guarantee. We back every window installation with a lifetime guarantee that includes a 25-year installation warranty and a 50-year material warranty so you can have peace of mind.
Get your energy-efficient windows and doors from Florida’s most trusted window replacement company so you can rest easy knowing that your new windows will protect your pocketbook from rising energy costs for decades to come.
Areas We Serve
Need energy-efficient windows for your home? Karoly Windows & Doors is here to help! We provide window and door installation services for homeowners in the following areas:
ENERGY STAR Window Installation Videos
Want to learn more about impact window installation and how it can help you save money on your electricity bills? Check out the Karoly Windows YouTube channel for more information, updates, and videos on this and other window-related topics! Here’s a quick video highlighting the benefits of impact windows and doors for your home:
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