5 Point Proof Comparison


We are happy to answer your replacement window questions, but we want to go one step better. We’ll show you the proof behind those answers; the reasons why Infinity from Marvin® is your best choice in replacement windows. Our windows meet and exceed the most stringent standards, but we know they must still meet an even higher standard: yours.

Join us at the 2014 Denver Home Show


Having served the Greater Metro area for over thirty five years, Gravina’s Window Center is a well-established company consistently recognized for outstanding service in FIBERGLASS window and door replacements.



KEVIN O’CONNOR, Host of this old house

Kevin O’Connor is the host of the award winning series This Old House and Ask This Old House. He is currently in his tenth season and also serves on the editorial board of This Old House Magazine.  In 2010 Kevin also began hosting his third series called This New House, which airs on the DIY network. In September 2011 Kevin published his first book, The Best Homes of This Old House.

Prior to his television career Kevin practiced finance and most recently was a Senior Vice President at Bank of America in the Commercial Real Estate Group. The balance of his finance career began in 1999 with BankBoston and subsequently FleetBoston in the Sports Finance Group. Kevin received his MBA from Boston University and his BA from The College of the Holy Cross. Kevin lives north of Boston with his wife and three children.


Josh Flagg likes setting records. Within the first four years of his career, Josh participated in four record sales, three of which were in Beverly Hills. He grew up on the Westside and graduated from Beverly Hills High School in 2004, jumping right into high-end residential real estate. Josh had the choice to either join the family business, which owns and develops shopping centers, or go a different direction. He chose a different direction Josh is also one of the stars of Bravo TV’s Million Dollar Listing

“He pampers his clients…” said one local Realtor, “In a way I have never seen beforeand I’ve been in the business for 25 years. I’ve seen Josh send chauffeured cars to his clients’ homes and send his clients up in helicopters to view properties. The best thing I have seen Josh do, though, was wrap an entire house in a big red bow before delivering the keys to the new owners. He is very creative, and that is why he is so successful. In Josh’s mind, there are no limitations.” 


Introducing LoĒ-i89 Glass for windows

Our enhanced performance glass …is even more enhanced.

Double-Pane, Clear, Air 0.48
Double-Pane w/LoĒ³-366, Argon 0.24
Double-Pane w/LoĒ³-366 and LoĒ-i89, Air 0.23
Double-Pane w/LoĒ³-366 and LoĒ-i89, Argon 0.20
7/8″ IG UNIT
Triple-Pane, Clear 0.37
Triple-Pane w/LoĒ³-366, Argon 0.25
Triple-Pane w/LoĒ³-366, LoĒ-180, Argon 0.20
Triple-Pane w/LoĒ³-366, LoĒ-180, LoĒ-i89, Argon 0.17

Introducing LoĒ-i89™, our new energy-saving 4th surface (roomside) coated glass. It offers more light transmittance, less reflectance and it now is available in a less expensive annealed version.

Yet it still delivers a center of glass U-factor of just 0.20 when coupled with our LoĒ³ or LoĒ² glass and argon fill in a double-pane unit. Without argon and with or without capillary tubes, the unit still delivers a U-factor of just 0.23 – perfect for high altitudes.

So if you’re ENERGY STAR compliant today, by adding LoĒ-i89 you’ll be compliant tomorrow as well.

What’s more, LoĒ-i89 is easy to clean and there’s no haze to mar the view. That’s our new LoĒ-i89, our enhanced enhanced performance glass.

Turn your double-pane windows into triple-pane performers.

There’s no need to go to triple-pane windows to meet the various energy-saving guidelines. No need to invest in redesigning your windows and altering your manufacturing processes either. A double-pane IG unit with LoĒ-i89 can meet the guidelines.

LoĒ-i89 is sputtered onto the indoor lite, the #4 surface, thus reflecting escaping heat back into the room and lowering U-factors. Coupled with our LoĒ² or LoĒ³ glass and argon fill, this double-pane unit delivers performance much better than clear triple-pane – a center of glass U-factor of just 0.20 compared to 0.37 with clear triple-pane.

To surpass the U-factor performance of our LoĒ-i89 double-pane unit, you would need to go to a triple-pane unit with a low-E coating in each gap.

Meet today’s strictest energy efficiency guidelines.

With a center of glass U-factor of only 0.20 (0.23 without argon) and SHGC of just 0.25, an insulating glass unit with LoĒ³-366 and LoĒ-i89 meets the most stringent energy standards – without going to a triple-pane unit.

This allows you to offer more double-pane window options that can meet the proposed ENERGY STAR guidelines throughout North America.

The advantages are more than clear.

In addition to providing maximum energy efficiency in a double-pane unit, LoĒ-i89 offers several other customer-pleasing benefits.

Its surface is smooth, making it easier to remove label residue and clean. And perhaps most importantly, there’s no haze to mar the view.

Naturally Cardinal IG units with LoĒ-i89 live up to the Cardinal reputation for long-range durability, delivering the industry’s lowest failure rate – only 0.20% over 20 years.

Give homeowners another reason to love LoĒ-i89 units – include Neat® naturally clean glass on the outside. Your windows stay cleaner longer and clean easier. Finally, protect your windows in transit as well as on the job site with Preserve® protective film.

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  Glass Performance   Visible Light
Solar Heat Gain
(Air / Argon)
Fade UV Fade ISO  
  LoĒ-180, LoĒ-i89   77% 0.62 0.24 / 0.21 0.27 0.61  
  LoĒ²-272, LoĒ-i89   70% 0.41 0.23 / 0.20 0.16 0.53  
  LoĒ²-270, LoĒ-i89   69% 0.36 0.23 / 0.20 0.14 0.51  
  LoĒ³-366, LoĒ-i89   63% 0.27 0.23 / 0.20 0.05 0.41    
  7/8″ Triple-Pane              
LoĒ-180, LoĒ-180, LoĒ-i89   68% 0.50 0.21 / 0.17 0.13 0.49  
LoĒ²-272, LoĒ-180, LoĒ-i89   62% 0.34 0.21 / 0.17 0.08 0.43  
LoĒ²-270, LoĒ-180, LoĒ-i89   60% 0.30 0.21 / 0.17 0.07 0.42  
LoĒ³-366, LoĒ-180, LoĒ-i89   56% 0.22 0.21 / 0.17 0.02 0.35    

Take your window U-factors to a new low – with LoĒ-i89.

LoĒ-i89 on the 4th surface of your windows allows you to get near triple-pane performance in a double-pane unit, and meet the toughest energy guidelines as well. Finally, LoĒ-i89 can be purchased in hurricane-resistant laminated glass in a variety of shapes and sizes.

To learn more about LoĒ-i89 and other Cardinal glass products, ask your contractor or architect.

Help choosing a new replacement window

Your Denver replacement windows company. We carry windows from Marvin Windows and Doors featuring their Ultrex Fiberglass Infinity Window. Choose Gravina’s for your new windows, patio doors and entry doors!  303-794-0490

Gravinas Window Center

Denver Replacement Windows
89 W Littleton Blvd

Littleton CO 80120 United States


Gravina’s Window Center

Great people to work with.  We recently did a full frame replacement of all the windows in our home with Infinity from Marvin Ultrex Fiberglass windows.  The windows are wonderful, the installation was  efficient and well done and the final finish (stained) was nicely done.  Gravina’s Window Center was recommended to us by friends and we can easily recommend to others. M & M, Littleton

Above review from YELP

Since 1973, Gravina’s Window Center has been the Denver Metro Area’s most friendly and reliable window replacement company.

Here at Gravina’s, we build long-standing relationships by taking the time to honor the values and needs of our clients. We are confident that we can offer you the highest quality replacement windows and doors in addition to the most personable and knowledgeable service.

In fact, Gravina’s Window Center has set the window and door replacement industry standard through honoring the values of a third generation family business. This means that here at Gravina’s Window Center, we treat our clients with the same attention and respect we would treat a member of our own family. From your initial purchase through your repeat business to come, we look forward to making your window and door replacement door dreams come true