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Find out the true benefits of triple glazed fiberglass windows in comparison to double glazed fiberglass windows.


Double Pane Windows vs Triple Pane Windows

If you’re deciding what type of glazing you want for your windows, it’s more than just looking at the fact that double glazing has two panes of glass, and triple glazing has three. All factors must be looked into in order to understand the true difference between the two glazing options. Here you will find all the answers you need for understanding the differences between double pane windows and triple pane windows including the difference in cost, energy efficiency, durability and more.

Double Pane Windows-Pros and Cons

Super Spacer Corner With SealantDouble glazing windows consist of two panes of glass with a spacer that separate them. It is required as a standard for all residential applications in Canada due to the harsher climate during the winter. Double pane windows can reduce up to 50% in heat loss, keeping your energy bills at a lower rate and in combination with a fiberglass frame, the overall energy efficiency of your fiberglass windows increase. The main benefit of double pane windows is the cost factor. The cost difference between double pane and triple pane fiberglass windows may vary. At Fibertec, the difference between the dual vs triple pane is approximately 15% while most companies reach about a 40% cost difference.

Frame Material
PROS AND CONS:When looking for an energy efficient window, the frame material plays a big role in determining the quality of the window. With a double pane window, fiberglass frames are the best choice because it is designed in such a way that the closed back frame (not all companies offer closed back frame) can support a double glazed window without warping. Double glazed fiberglass windows may cost more up front, however over time you will be saving money. Read more here about why fiberglass is the best window frame material to use.

Spacer Used
PROS AND CONS:With double glazed fiberglass windows, one spacer is used to separate the panes of glass. The space left between the two panes must be correct in order to achieve proper air flow between the panes of glass. Exceeding or not achieving the right space between a double glazed window can have a great effect on the energy efficiency of the window.

Gas Fills
PROS AND CONS:Double pane fiberglass windows can have a gas fill between the panes of glass for added thermal efficiency. Gases such as argon gas and krypton gas can be used as an insulator. Argon gas is often seen as a more popular choice because it is also significantly lower in price than krypton gas and is, in most cases, a more suitable gas to use for insulating fiberglass windows.

PROS AND CONS:Dual glass panes perform much better than one single pane of glass, not only because of the space between the glass. The glass itself can act as an insulator as well. By using Low-E coating on the glass, infrared light is kept out while allowing visible light to enter your home. Heat mirror film is also used in combination with double glazing fiberglass windows for added insulation.

Inquire about our Double Pane Fiberglass Windows
See our heat mirror windows section for more information.

Triple Pane Windows-Pros and Cons

Super Spacer Triple PaneTriple pane windows are an exclusive step up from double glazed windows. With three panes of glass and two spacers instead of one, triple pane windows become much heavier than double pane windows, however if fiberglass is used for frame material, it is able to withstand the weight of a triple glazed window. Despite the weight of a triple pane window, there will be no effect on the everyday use of your windows. The reason why people are much more attracted to choosing triple pane windows is because there is a great difference in performance between a double and triple pane window. When comparing factors such as the SHGC, or U-values, there is an approximate improvement of 20-30% in a triple pane window’s energy ratings. In most cases, companies will upcharge triple glazed windows due to the fact that other companies use a double pane frame and try to put a heavier triple pane unit inside the same frame design and try dissuade customers from using triple pane units by increasing the pricing. At Fibertec, we are able to offer a fair price difference because our closed back frame was designed to easily hold a triple pane unit, and therefore we can provide a trustworthy fiberglass window, both as a triple pane or double pane.

Frame Material
PROS AND CONS:As mentioned before, triple glazed windows are much heavier than double glazed windows and need a strong frame material that can be durable enough to last. Due to the properties of fiberglass, fiberglass frames are able to withstand heavy loads without twisting, warping or sagging overtime.

Spacer Used
PROS AND CONS:Triple pane windows have two spacers that separate the panes of glass in a triple pane fiberglass window. Fibertec uses a spacer called the Premium Super Spacer rather than a warm edge spacer that is commonly used. The premium super spacer is made from a superior quality silicone resistant to UV light oxidation and offers great argon gas retention for higher energy efficiency.

Gas Fills

The same gas fills used in double pane windows are used in the same way for triple pane fiberglass windows. The only difference is that triple pane fiberglass windows have gas injected into both air fill spaces between the panes of glass, significantly increasing the energy efficiency of a triple glazed fiberglass window.

Glass Used
PROS AND CONS:Triple glazed fiberglass windows have three panes of glass. Two of three layers of a soft/hard coat low-emissivity (Low-E) film can be added on the non-exposed surfaces of the glass (one per chamber). By having three layers of glass, your windows are able to reduce outdoor noise transmitting through the windows.

Inquire about our Triple Pane Fiberglass Windows
In Summary…

Triple Vs Double Glazed Windows

Comments (45)

  1. Simha S Mendelsohn
    July 27, 2014

    3,500 sq. ft. house replace all widows, using same casing and frame. using a combination of fibreglass-wood.

    Thank You,

    Simha S Mendelsohn
    Toronto, ON
    (416) 785 1488

    • Fibertec Windows
      July 28, 2014

      Hi Simha,
      We have sent your inquiry on wards to our sales department and will be getting in touch with you as soon as possible.

      Best Regards,
      Fibertec Windows

  2. hossein
    October 6, 2014

    I recently replaced all windows in my old house, but unfortunately have sound pollution problem with my new window , specially my big bay window in family room.Do you think if i Use triple glass it would help.

    • Fibertec Windows
      October 8, 2014

      Hi Hossein,
      Having triple pane windows for the purpose of eliminating as much sound transmission as possible will only show slight improvements from a double pane window. By using a double glazed interior surface laminated glass, you can achieve an STC rate of 32 and a double glazed double laminated will give you an STC of 42. The thickness of a triple pane window will not show a significant difference.

      Good luck,
      Fibertec Window and Door Mfg.

  3. Ken
    November 27, 2014

    Wondering if triple pain will make much of a differents over a double pain for sound in the bed room? And is retrofit a ok way to go when replacing windows?

    • Fibertec Windows
      December 4, 2014

      Hi Ken, I had mentioned in a previous comment that triple pane windows will not greatly improve the sound transmission in a bedroom. There will be improvement, however not much. And yes, it is perfectly fine to step up the technology and use fiberglass windows for your home.

      Best Regards,
      Fibertec Windows

  4. James
    January 19, 2015

    Hi folks

    Does Fibertec make a window that will allow you to look out but not in. One the problems I have seen with this type of window is at night with lights on you can see in from street .


    • Fibertec Windows
      January 22, 2015

      Hi James,
      Try looking into LoE windows. Different types of LoE coatings can add a dark tint to the window while still allowing natural light to enter your home. Although LoE windows do not offer full tints on windows, they are extremely useful in saving energy and are a great solution to what you may be looking for. Send us an email to and we will be able to speak with you more in depth in regards to meeting your needs. You can also take a look at our LoE Glass Section to learn more about the different glass options.
      Good luck,
      Fibertec Windows and Doors

  5. Cali Salzmann
    January 30, 2015

    Could you send me a quote for a triple glazed sliding doors, windows 6( 1.68x 2.70 roughly), 90 x 60 ( for toilet room) and 1.20 x 80 for single bedroom. Or, even better, what size widows and sliding doors do you fabricate and how much do they cost? I am planning to build a house as close to net zero energy as i can get and am doing the research part of materials cost at the moment. The house would be a two bedroom house, living/dining / kitchen open plan area onto a garden, with a separate toilet, a bathroom with shower and bath. The house is a steel frame, orange board ( or eco tec-cement blocks- haven’t decided yet) house, single story. How long would it be between ordering and delivery, and what would delivery to Cranbourne, Victoria, Australia be?
    Thank you
    Cali Salzmann

    • Fibertec Windows
      February 2, 2015

      Hi Cali, please send us an inquiry via or through our contact form and our sales department would be more than happy to get in touch with you.

  6. Ellen Banks
    June 19, 2015

    Finding the right windows for your home can be a little tricky if you don’t understand your options. I didn’t realize that triple pane windows are so energy efficient. Triple pane may be a good option if you’re looking to save money in the long run.

  7. gayle palmer
    August 8, 2015

    I have a wall of double-paned windows in a steel frame. Some have failed several times so that there is moisture between the panes. Would a 3-pane be less apt to fail?

    • Fibertec Windows
      August 11, 2015

      Hi Gayle,
      Having a triple pane unit would be irrelevant to the chances of seal failure being more or less apt; seal failure can happen regardless if a unit is double or triple pane. In your case, you have steel frame windows and a steel frame has a very high expansion and contraction ratio to glass, increasing your chances of seal failure. When the frame contracts, there is moisture that sits on the bottom sill causing seal failure. The expansion and contraction rate of fiberglass and glass are the most similar in comparison to other frame materials which is why fiberglass windows may be a good option for you to consider for replacement. You can get in touch with us for more information at
      Best of luck!
      Fibertec Windows and Doors

  8. Alice
    October 10, 2015

    I’ve seen a triple glazed window where the middle pane has shattered! Is this poor fitting or would impact from something like a bird hitting the outside pane cause this? Is this covered by warranty?

    • Fibertec Windows
      October 14, 2015

      Hi Alice,
      It is very likely that the middle pane was able to crack in a triple glazed unit. There are many different reasons for that happening, which may include having a defective pane of glass in which the dent grows due to any impact put on the sealed unit, or from excess argon gas, and there are many other reasons. In regards to the warranty, every situation will be different. I hope this answered your question.
      Fibertec Windows and Doors

  9. Matjaz
    October 20, 2015

    what’s the Rw value for triple glazing panel: 6:16/4/18/4? is it 36 db?
    The thing is a have brand new windows, which I think are less noise proof than the old ones, which were 4/16/4.
    If I lean an ear on the new window (on the glass) there’s more noise to hear compared to the old one (luckily I didn’t change all the windows and therefore can make comparison). Is the noise which is transformed through the glass and can be heard if you lean an ear to the glass good indicator of soundproofing?

    Thank you for your reply!

    • Fibertec Windows
      October 29, 2015

      Hi Matjaz,
      Thanks for your comment and interest in our article. I wouldn’t say that putting your ear close to the window is the greatest indicator of determining whether or not your new windows have improved the sound transmission in your home. Noise can even be transmitting from around the perimeter if the installation was not done air tight. There are other contributing factors but the unit itself can also be one of those factors. Feel free to get in touch with us in regards to the other half of your windows!
      Best regards,
      Fibertec Windows and Doors

  10. john clark
    October 26, 2015

    How much difference does it make between installers? For Example, Is the difference between installing a window in a brick opening versus a wall with siding that much of a difference? How much experience does it make for installers to know the techniques between them. Our windows in texas has metal headers!!

    • Fibertec Windows
      November 2, 2015

      Hi John,
      Having an experienced installer can make all the difference in enjoying the actual quality of your windows. Many people that complain about a problem with their windows usually end up having an issue caused by poor installation. Whether it be the caulking, leveling or actual installation, it is important and very highly recommended that you have your windows installed by someone experienced in the field.
      Best regards,
      Fibertec Windows and Doors

  11. Ahman Millener
    December 19, 2015

    I have been preparing a Shipping Container Apartment to build. I see you mention the difference between Fiberglass frame and Metal frame. I just wanted to add that the frame itself being Fiberglass makes a major difference in sound quality also. Where Metal conducts noise, Fiberglass Dampens noise. This is why I want to go with Fiberglass, so that when I use Closed Cell Foam and Fiberglass i’ll get the best sound reduction, since the Shipping Container are Metal. Wood framing will also help with dampening.

  12. Komal
    February 10, 2016

    Hello Fibertec,

    We recently moved into a new home which is closer to the main road. Due to this especially at night the children constantly are waking up due to the noise of the cars and motorcycles passing by. I am assuming we have dual paned windows but am not 100{a1e3408b28e349066677ffa6d2c9947b97125fce257a48f3930b2b2e7fae95d0} positive.

    What what you recommend we do to help reduce the noise significantly? We still want to be able to open the windows to let fresh air in once in a while. I am so confused about dual pane, triple pane, using gases, etc. Please enlighten me.

    Thank you,

    • Fibertec Windows
      February 12, 2016

      Hi Komal,
      We understand you situation. In terms of the glazing of your current windows, I would have to speak with you further to determine whether they are dual or triple pane. Having triple pane windows for the purpose of eliminating as much sound transmission as possible will only show slight improvements from a double pane window, although many people tend to say that they have experienced a difference in sound transmission with triple pane windows. I’d like to discuss this issue with you further, feel free to shoot us an email at and we can definitely help you out.
      Best Regards,

      Fibertec Windows and Doors

  13. Dally
    March 25, 2016

    I live on route 9 and have changed Windows many time to triple plane
    Still car noise comes in maybe a low hum and big bank when large vehicles pass through
    And the road is at least a mike put

    • Fibertec Windows
      April 1, 2016

      Hi Dally,
      As previously mentioned, triple pane does not really help with sound transmission. It may make a slight difference, but nothing substantial
      Fibertec Windows and Doors

  14. Vinnie
    May 17, 2016

    What are the specification of your tripw glazed windows? U value, VT, SHGC?

    • Fibertec Windows
      May 24, 2016

      Hi Vinnie,
      Each window style has different specs. If you go to the windows section of our website, on the left side you will see technical specifications as well as energy ratings. Under energy ratings you can find the U Value, VT and SHGC ratings.
      Best regards,
      Fibertec Windows and Doors

  15. Ken thrasher
    July 17, 2016

    Will triple pane glass eliminate condensation

    • Fibertec Windows
      July 20, 2016

      Hi Ken,
      This all depends on the frame material you are using. When fiberglass windows are installed properly, they will provide a tight seal around the perimiter of the opening, preventing condensation. Fiberglass will also prevent condensation by expanding and contracting less than other frame materials, allowing for sealed unit integrity to be maintained at all times, no matter the weather.
      Hope this helps!

  16. Linda Bigelow
    December 11, 2016

    We’re looking at building a new home in Calgary, Alberta. This home has a patio door in the kitchen. I’m worried about it freezing closed in the winter like our storm doors do. We have to leave the windows open in the storm door all winter to ensure we’re able to open them when we want to. We have the option of replacing the patio door with a window and then adding a regular door to our kitchen. How do the patio door perform in the winter months?

    • Fibertec Windows
      December 19, 2016

      Hi Linda,
      All of our fiberglass windows and doors are built intentionally to perform exceptionally in harsh climates such as yours in Alberta. The patio door is the only all fiberglass component system in the industry and offers a very tight seal. French doors are also a great option in your scenario. Please feel free to get in touch with us at and we can further help you with your project.

      Happy Holidays!
      Fibertec Windows and Doors

  17. Anthony S.
    December 18, 2016

    Looking to upgrade windows in a 1966 house sometime in the next few years. Current windows are single and a half pane windows, with kind of a window you remove to expose a screen if you want air in from the outdoors. I went to a big box hardware store and I feel like they may have been trying to rip me off – they have quality fiber glass frame double pane windows for $250-300, but they told me to get a tripple pane window it may be almost $1,300 for a single window. I’m not paying a $1,000/window markup – I think that pretty much squelches any long term energy savings.

    • Fibertec Windows
      December 19, 2016

      Hi Anthony,
      The prices for the window will all depend on the window system as a whole – the glass, the frame, the sealant used, hardware used, etc. Although fiberglass windows can get pricey, the price difference between a double and triple pane is about 20{a1e3408b28e349066677ffa6d2c9947b97125fce257a48f3930b2b2e7fae95d0}. I cannot speak for the prices of the store you were at, but maybe we can help you find what you are looking for. Feel free to send us an email to and we can help you out further.

      Happy Holidays
      Fibertec Windows and Doors

  18. Dorie newland
    December 20, 2016

    Where can you buy fiberglass windows and frames in Kentucky? Live close to Lexington, and have someone who can install the window, but do not know how your windows stack up to other fiberglass windows. Thanks,

    dorie newland
    NIcholasville, Ky 40356

    • Fibertec Windows
      December 23, 2016

      Hi Dorie,
      You can order from us direct – we have customers from your area which may possibly be a good reference for you to see our windows installed and how they perform. Please get in touch with our sales team at and we can help you out further.

      Happy Holidays
      Fibertec Windows and Doors

  19. Marcela K.
    January 7, 2017

    We have double pane windows and we get frost on them constantly (we live in MN). The frost is NOT between the panes, only on the inside pane (the side that faces the room) and only at the bottom of the window, not the whole. My question is, if we switch to triple pane, would frosty window be still an issue? Thank you.

    • Fibertec Windows
      January 11, 2017

      Hi Marcela,
      Your issue is condensation. Condensation on windows occurs due to the cold air that comes from the outside and meets with the heated air from your HVAC system on the inside. The cold air can be due to having a poor seal around the window, or if you have vinyl windows they may have warped and are now allowing air to leak through the perimeter, or through the sash. If you have a vent under the window, this may be even more of a problem because the heat is directly making contact with the cold air from around the window. You should look into changing the entire window to a triple pane fiberglass window. Having three panes of glass and having a strong frame will most definitely solve your problem.

      Hope that helps!
      Fibertec Windows and Doors

  20. Candace
    May 29, 2017

    What would you estimate is the general lifespan of triple-pane windows? If you keep the casings in good condition (wood)?

    • Fibertec Windows
      June 14, 2017

      Hi Candace,
      This will highly depend on the type of frame material used for the triple pane window. Fiberglass framed windows will have the longest lifespan with the least maintenance.

  21. Ridley Fitzgerald
    October 5, 2017

    It’s good to learn about double glazed and triple glazed windows. It makes sense that triple pane windows are more efficient, but are much heavier. I bet they are more expensive too, which is a problem for us. We want new windows, and double glazed may be the one we go with.

  22. Ernest
    November 16, 2017

    Just a simple “THANK YOU” for an informative article with pictures, so that anyone can learn the difference between double and triple pane windows.

    • Fibertec Windows
      December 22, 2017

      You’re welcome!

  23. Peter
    March 11, 2018

    Can you pop out double pane window and replace it with a triple pane? I have bedrooms with heavy sun and would like added insulation and sun reflection. Windows are just 5 years old. They are hybrid frames with aluminum covered exterior and pvc interior.

    • Fibertec Windows
      March 20, 2018

      Hi Peter,
      This will greatly depend on the profile of the frame and whether or not it will allow for the full depth of a triple pane sealed unit. This differs from manufacturer to manufacturer, but it would be best to consult with the company who you got the windows from, or to speak with a glazier who could help you make that decision.


  24. How To Soundproof A Window | 7 Tips You Need To Know For A Quiter Room
    October 10, 2018

    […] you have some of the newer better insulated double and triple pane windows, then they not only conduct more heat and cold from the outside in and vice versa but also the […]

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