The below table demonstrates EnerLux’s different glass packages and their center-of-glass energy performance.  To help explain the Glass Package labels please refer to this guide:

366 = Cardinal LoE-366

^3 = Triple pane

i89 = Cardinal i89 interior LoE coating

Glass Package U-Factor R-Factor SHGC VT Panes GAS Components
180 0.26 3.8 0.70 80% Double Argon LoE-180 & Clear
270 0.25 4.0 0.37 70% Double Argon LoE-270 & Clear
366 0.24 4.2 0.27 66% Double Argon LoE-366 & Clear
340 0.24 4.2 0.18 39% Double Argon LoE-340 & Clear
180 0.13 7.7 0.56 70% Triple Argon LoE-180, Clear, & LoE-180
270 0.13 7.7 0.33 62% Triple Argon LoE-270, Clear, & LoE-180
3663 0.13 7.7 0.24 57% Triple Argon LoE-366, Clear, & LoE-180
340 0.13 7.7 0.15 34% Triple Argon LoE-340, Clear, & LoE-180
1803 + i89 0.12 8.3 0.53 68% Triple Argon LoE-180, Clear, LoE-180, & i89
3663 + i89 0.12 8.3 0.24 56% Triple Argon LoE-366, Clear, LoE-180 & i89

Performance data calculated with Lawerence Berkeley National Laboratories’ Window 5.2 NFRC 100-2001.

All energy values are based upon a 90% gas fill level and 3 mm double strength glass.


U-Factor – A measure of the rate of non-solar heat loss or gain through a material or assembly.  It is expressed in units of Btu/hr-sq ft-F (W/sq m-C).  The lower the U-factor, the greater a window’s resistance to heat flow and the better its insulating value.

R-Factor – A measure of the resistance of a glazing material or fenestration assembly to heat flow.  It is the inverse of the U-factor (R=1/U) and is expressed in units of hr-sq ft-F/Btu.  A high –R-value window has a grater resistance of heat flow and a higher insulating value than one with a low R-value.

Solar Heat Gain Coefficient (SHGC) – A measure of how well a product blocks heat caused by sunlight. The SHGC is the fraction of incident solar radiation admitted through a window (both directly transmitted and absorbed) and subsequently released inward. SHGC is expressed as a number between 0 and 1. The lower a window’s solar heat gain coefficient, the less solar heat it transmits in the house.

Visual Transmittance (VT) – A measure that shows how much light comes through a product. The visible transmittance is an optical property that indicates the amount of visible light transmitted. VT is expressed as a number between 0 and 1. The higher the VT, the more light is transmitted.

LoE-180 High Solar Gain Glass

Glass Package 180

Cardinal LoE -180 delivers excellent cold weather performance – its insulation value (U-factor) is a low 0.26, and with a high solar heat gain coefficient (SHGC) of 0.69, it lets the winter sun’s heat pass into the home. It also blocks 71 percent of the sun’s harmful UV rays. While blocking out the cold and UV rays, it lets the daylight stream in – more light than ordinary low-e glass.

LoE-270 All Climate Glass

Glass Package 270

Cardinal’ss LoE-270® glass is the perfect solar tuned glass for all season comfort. It reduces solar heat gain by 50% or more when compared to ordinary glass. Although it is a clear glass, LoE-270 even outperforms ordinary tinted glass typically used in sunny climates. And though it’s coated, LoE-270 lets the light shine in to warm your house during the cooler winter months.

LoE-366 Low Solar Gain Glass

Glass Package 366

The full-year benefits of LoE -366 can be clearly seen. When the temperature soars in the summer, ordinary window glass just can’t beat the heat. Tinted glass spoils the view. LoE -366 is formulated to reject solar heat while maintaining attractive visibility. So it keeps the heat out while letting light in. As a matter of fact, LoE -366 glass is our ultimate in performance and clarity among all of Cardinal’s clear coated products. What’s more, LoE -366 provides the ultimate in fading protection. It blocks 95% of the sun’s damaging ultraviolet rays – a leading cause of fading (visible light also contributes to fading) – so your furniture, carpets, curtains and wall coverings stay beautiful for years.

LoE-340 Solar Control Glass

Glass Package 340

When it comes to reducing solar heat gain from the blazing western sun, LoE-340 simply has no equal. And because it’s not tinted, you enjoy a number of other advantages as well. First, there’s the cost savings of no tint. Then you avoid the disadvantages of tinting: the potential for thermal stress breakage and the potential need to heat treat the glass. Tinted glass has several other glaring deficiencies. Regular tinted glass works by absorbing sunlight, so the glass becomes hot in the sun. The color of the glass also changes with its thickness. On the other hand, LoE-340’s appearance and performance remain the same regardless of glass thickness. What’s more, LoE-340 has a very high LSG (light to solar gain ratio) of 2.17. So even though solar gain is being controlled, plenty of visible light is still allowed inside.

LoE-Quad 452+ Solar Control Glass

Glass Package 340

In hot, sunny climates, Quad 452+ clearly outshines ordinary window glass. It is formulated specifically to manage solar heat gain while maintaining clear views, taking more of the burden off the AC unit to keep conditions comfortable inside. It also provides exceptional fade protection, blocking 99% of UV rays from reaching the interior, protecting your furniture, carpet, and other furnishings to a degree thatis comparable to laminated glass. One other benefit is that Neat+ comes standard on all Quad 452+ glass repelling 40% more dust and dirt than uncoated glass.

LoE-i89 Energy Booster

Glass Package i89

Give your windows that extra boost of performance with one additional LoE coating on the interior surface of your windows.  With our triple pane IGs, i89 will boost the full-frame energy performance by 0.02 U on average, however there is a slight reduction in condensation resistance.

  • Excellent
    Based on 48 reviews
    Neil Lichtman
    Neil Lichtman
    We have been interested in adding a fiberglass window to our product line. We finally found Enerlux, and Zach Birchel did not disappoint. We worked for a year to land a commercial project, and everyone at Enerlux was extremely helpful in getting the project completed without difficulty. We even ordered three openings wrong, and they turned around and shipped the new windows so the project was not delayed. THANK YOU!
    John White
    John White
    Six stars -esp in the context of the USA residential window industry today Let me state at the outset some of my comments will be unguarded, but I want to be taken seriously and not for an amateur, paid shill or bot with readers facing the awesome challenge of finding windows that will last 50 plus years and not break the bank. It’s manifest that most established American widow makers have gotten greedy and lazy, focus on marketing and expensive dealer networks, an in many cases , cheapened the quality of heir product. I know, I’ve been there. As a small builder in process of building a house for my daughter, I scoured the universe for well over a year trying to max out her window budget. Once you eliminate Euro windows as too bulky and frames too wide, and real fulfillment questions from overseas (and on time ? And what if a window broken in transit ? That’s a 3 month delay even with the best customer service; I’ve know several boutique Italian manufacturers will send a replacement air freight at 3x the cost of the indoor itself , but if you have to ask how what those windows cost in the first place, you cant afford them) Also the superiority of fiberglass as a frame material becomes quickly apparent. , and Enerlux corner design in particular. Durability, strength, thin lines, top euro quality hardware, etc. Whether you are going for a modern or traditional look, if your budget allows for anything beyond an Anderson 100 series, you HAVE to look at Enerlux as an option. Look, SChuco, Loewen, Western , Raynor , even Marvins high end, make great windows and offer solid customer service ….. if your are paying $100k plus for an architect, or have more money than brains, , hey go for it….you cant go wrong with them . A number of my clients have ; BUT at a steep price differential, and NOBODY has a better quality frame or , customer service than Enerlux. (And for course they are all using-or should use-Cardinal glazing units .While a smaller firm, there is NO way they wont be around for the lifetime of your windows. And in this case, buy AMERICAN -makes GREAT sense from a fulfillment and follow thru service standpoint. Their product, attention to detail and customer service make it impossible for this company not to grow and endure. Customer service is UNPARALLELED- just pick up the phone and try it-you get a real attentive knowledgeable person. You must pay considerably more to get a remotely comparable Marvin ( let alone Weathershield or Pella (dont even start !! LOL ) custom color fee set ups are a fraction of the bigger players. Unless you are seeking passive house standards, are willing to try some of the newer-but unproven - hi-tech glazing options being offered by some manufacturers in the western states, OK with Euro UPVC, not USA vinyl (nothing wrong with them if UV exposure reasonable and youre ok with the look, and size limitations ) can wait out long lead times, countenance dealing with a middle man importer (will they be around ten years from now?) Buying quality windows is a jungle and /or expensive these days- do yourself a favor - go to their web site, dive deeply into it , and get your first quote from Zach Birkel and his team. And if you are in the Mid ATlantic area, happy to show you ours.
    Ardis Koehn
    Ardis Koehn
    I'm a retired teacher and wanted the best windows for the buck, so I researched the internet for fiberglass windows and doors. I found them (ones superior to others with incredible price)...EnerLux Windows made in Crete, NE! I even toured the plant with the owner, Mark, where they were made and was so impressed. Hiring an experienced window installer who had never installed this brand commented, "These are awesome," made me feel great. EnerLux even had one of their top guys, Zach, come out 2 times to answer our questions and assist! Beautiful windows!
    ryan alger
    ryan alger
    We ordered triple pane windows for a client to meet our energy demands. The windows are arrived in excellent shape using a dedicated shipper. the windows themselves are of excellent quality and without the usual adhesive bubbles you see on most new window packages. The customer experience with Enerlux from quoting to ordering is an easy, no pressure kind of experience. I was able to see the difference in price from double to triple pane as well as what/how different sizes affected our quote.
    Nate Lewis
    Nate Lewis
    These are the best windows ever! The installers, who install every major brand, spontaneously said the same thing multiple times. They put together a custom glass package to meet my local fire code regulations and to also just nearly completely wipe out noise problems at my home, that no other major manufacturer could or would come close to doing; the windows all work (!) seamlessly when installed square (unlike the other major brands that cost 2 or 3 times more with less quality); the air penetration is near-zero and the thermal properties are great; the frames and hardware are well built, and the Enerlux people were unbeleivably cooperative and supportive; Krystal is off-scale helpful and patient and responsive; she gets five stars just by herself! I did my whole house with Enerlux and would do it again in a heartbeat!
    We have had a great experience working with Enerlux. Our first order was $40k worth of triple pane windows for a $175k reno and they did not disappoint. We just did an initial walk through for a 600k reno and we all smiled when the homeowner mentioned triple pane windows. In our business having a source that you can rely on for hi end products made in the USA is invaluable. Enerlux you are on the RLRider team!
    Tao Gong
    Tao Gong
    We installed all EnerLux windows on our new build earlier this year. We worked closely with Mark, who was amazing to work with. He is patient, thoughtful and efficient - the service was beyond what we expected and imagined. He gave us suggestions that made our home even more energy efficient and even coordinated the delivery so the installation could be done prior to snowfall. Our builders also enjoyed working with Mark. The windows are also very high quality and installation went smoothly. We are really glad we picked Enerlux windows
    Sean Bottger
    Sean Bottger
    After 20 years of remodeling and construction in the Lincoln area, I have installed and worked with the majority of window brands. When deciding what window to use for a new house, my family moved into. I stumbled across Enerlux. Boy am I glad that I did. Everyone in the company was a pleasure to work with and these windows are by far the best windows I have ever installed. The difference in noise and air quality in our home is massive. I have already referred them to numerous other people and will continue to share my experience. They are a small company with quality set as their number one goal. I look forward to working with them in the future. Also, a big shout out to Zach Birkel who did an amazing job working with on the sale from start to finish!
    Matlock Jeffries
    Matlock Jeffries
    Great interactions with Enerlux, and so far appears to be a great product. Ordered triple pane windows for a near-passive-house new build. High quality frames and finishing, high NFRC performance. Delivery was straightforward and easy. No negative things to say, everything went smoothly.

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