Double Glazed Windows: What You Need To Know

Hanging out on the porch will always be a great way to ween those pleasant summer days away but what happens when Old Man Winter comes knocking at the door? Unfortunately, our perfect porch swing days are usually numbered once the seasons change and depending on where you are in this great country, keeping your home warm through all those BRRRRR months may become a challenge, let alone your porch!

Double glazed windows are meant to protect our family and loved ones from the elements and in some particularly cold environments, they are an outright necessity. They can be expensive to install and complicated to understand so we decided to put together this EPIC guide to the wonderful world of double glazing.

Hopefully, this guide will help you keep you and your house nice and toasty till you can enjoy your perfect porch swing once again when summer comes around!


Double Glazed Windows: Why You Need Them

Insulation is the name of the game now, when it comes to making a comfortable home that is also energy-efficient. However, insulation isn’t just about how your walls are built, or how you manage to seal doors and windows against leaks. These days, insulation is also about window design. After all, glass panes can transmit heat and light directly, be it from inside to outside, or the other way around.

double glazed windows 8While theoretically, you won’t need to have windows if you have enough ventilation, windows provide important aesthetic and psychological factors in the way our homes are built. Simply put, we need windows so that we can see what’s happening outside.

For this reason, it’s important to come up with insulation solutions that can help with keeping a house energy-efficient, taking into account the windows as well. And for this, the solution is in the form of what is known as double glazing windows.

What Are Double Glazed Windows?

Double glazing windows is accomplished by using two panes of glass with a space in between. That space can either have normal, dry air in it, or a special gas.
The mechanics of this design are simple: the two panes of glass with the space in between creates a temperature buffer layer, preventing heat from leaking outside through windows in the cold months, and at the same time preventing the heat from outside to leak into the room through the windows during the summer months.

Where are they useful?
Double glazed glass is primarily useful for windows that are located in main living areas, such as the kitchen, dining room, and living room, where, chances are, the windows will be much larger than they usually would be in the rest of the house. This also applies to window-type doors that could be used in balconies, and even sliding doors for patios.

Basic CMYKThe reason for this is that the heat loss for smaller windows – like, say, attic windows, or bathroom window vents – are negligible enough that the cost of installing double-glazed windows will outweigh the potential savings. In addition, given the bulkiness of double glazing windows, smaller window sizes would be rather impractical or even more difficult to install.

Double glazing is most useful for areas where the window frames are largest, such as porch enclosures, particularly uPVC porches. That’s because uPVC frames can be adapted especially for the thickness or width of the double-glazed windows’ two-pane system.

What’s the difference?

As mentioned before, the big difference that double glazing windows can give is primarily in how it stops the transmission of heat from one side of the window to the other. This creates an effective insulating layer – practically a wall, when it comes to insulation efficiency. This may not sound like much, but over time, the cost of inefficient insulation can skyrocket, and can trigger a series of other expenses that could have been avoided with by installing double glazed windows in the first place.

double glazed windows 3How Do You Produce Double Glazed Windows?

Double glazing sounds simple to make: all you need are two glass panes of the same size, and then you should have a small space in between them – which you either keep empty, or fill up with a gas other than standard air. While this may sounds simple enough, the truth is, it can get very complicated.

Weather-specific glass types

While one can technically use practically any type of glass for double glazed windows, the fact is, if you want the most efficient type, then you have to use what are known as Low Emissivity, or Low E, glass.

Low E glass contains a practically unseen metallic layer, and depending on the type of layer, you come up with the following:

1) High solar gain – this kind of Low E glass is best suited for areas with cool summer seasons and extremely cold winters. This kind of Low E glass reduces heat loss and increases heat within the house.

2) Moderate solar gain – If you lie in an area with mild summer and winters, then moderate Low E glass is your best choice, as it lets in some heat, without losing any of the light in the process.

3) Low solar gain – this type of Low E glass offers a high amount of protection from ultraviolet rays. This is best used in areas with very hot summers and winters that are moderate at most in intensity.

As mentioned before, some double glazed units have an inert gas pumped into the space in between the two glass panes. Argon is usually the gas of choice, due to it being denser than air. This extra density makes it a better insulator, as it will block more heat from crossing over between the two sides of the double glazed glass pane. If special gasses are being used, then it should be no surprise that the main structure that surrounds the glass panes and the space in between also need careful consideration.

double glazed windows 2For one, to offer the best sort of insulation, the two panes of glass should be put in position and sealed into place. This means that whatever material will be used to fix the glass in place should not only function well as a sealant, it should also be able to last through extreme weather, as it will be exposed to sunlight and a wide range of temperatures. The frame itself has to be sturdy, too. This is usually made with light metals like aluminum, or with stiff plastic components, such as uPVC. These materials should also be compatible with the sealant, and should have no problem either with the gas that will be used. As you can read, it’s all about coming up with the best design that will stay sealed, with the layer in between keeping structural integrity so that the gas in it won’t leak out.


Pros and Cons

Installing double glazed glass window components have many advantages for the normal household, such as the following:


Home security

You can incorporate many kinds of security systems and manual locks into doors and windows that are adapted for use or are specifically designed to accommodate double glazed glass components. If you’re using double glazed glass windows in many parts of the house, you automatically will give yourself more security options than if you hadn’t used them.


There is little maintenance required with double glazed glass panes. However, it’s a good idea to use cleaners that won’t degrade the sealants or any part of the structure that keeps the glass panes in place.

Saving money thanks to energy efficiency

With fuel costs now becoming higher as years go by, the use of double glazed glass windows is necessary, if you want to lower your energy consumption. You can even think of it this way: even if you will have a large cash expense thanks to the usual double glazed prices, you will be able to recoup all those expenses through your savings, thanks to lowered fuel and utility costs.

Reducing noise pollution

If you think you’ve seen the construction of a double glazed window before, then you should think about the first time you’ve seen the windows that are used in recording studios.

Double glazed windows can reduce noise levels from one side of the glass window to the other. This is because the space in between that is filled by a gas not only prevents heat from passing through, it can also trap vibrations made by sound, hence preventing most of the surrounding noise unable to go through the double glazing.

This noise suppression quality may actually be a plus for you, especially if your house is in a naturally noisy neighborhood. The use of double glazed windowpanes will help in raisin the value of your house, should you ever decide to sell.


Double Glazing Cost

Unfortunately, you should carefully do your calculations and compare what you’re paying now for fuel, double glazed windows prices and how much you can divide your cost of acquisition versus what your savings are on a monthly basis.

Sad to say, double glazing (and even secondary double glazing and triple glazed windows for that matter) still has to make sense from a financial perspective. Otherwise, you may end up with a great project… that doesn’t do even half of what was promised.


One of the weaknesses of double glazed windows is that while it can prevent heat from crossing from one side to another, the window will still let sunlight in, and this can start heating up the insides of the house or apartment.

The obvious solution, of course, is to apply a layer of tinted material on the double glazed windowpanes themselves, but the fact is, this will also lower visual clarity through the windowpanes themselves. This will make the insides of the home darker than they should be


While these systems are low maintenance by nature, you have to consider the following issues as signs that you may have to replace your window or consider double glazing repairs:

1) The glass is broken. Regardless of whether or not the second pane of glass is still in one piece, the effectivity of the double glazed glass window is now effectively nonexistent. After all, the idea is that you’re supposed to have that space in between each pane. If one or both panes are broken, then the heat-blocking capabilities of the windowpane are permanently removed as well.

2) If the sealant material is already cracked or crumbly, chances are you should replace that whole window anyway. The gas that was being used in the space between the panes may now effectively have dissipated through a leak in the frame sealant.

Other Considerations

double glazed windows 9If you’ve decided that you’re already going to use double glazed glass windows in your house, then it’s a good idea to consider the following:

If you’re going to do this as a do-it-yourself home project, it’s a good idea to read up on what sort of materials, such as sealant or the material of the double glazed frame itself, you should use for your house. For example, given what sealant will work well with uPVC, you should think about how these sealants will affect non-frame materials.

Aside from that, you should also read up on the official dimensions and construction for double glazed windows that will be up to code. For example, it’s generally a good idea that the space in between the two panels of glass should be about half an inch, so that the gas inside the space can be given enough leeway to reflect, absorb, or slow down heat dissipation.

It’s been mentioned before that double glazed windows are low in terms of maintenance costs. However, you should be aware that you should use cleaning materials that won’t compromise the sealant material or the frame. For example, if you’re using uPVC as the framing material, then you should make sure that your cleaner for the double glazed windows won’t affect the uPVC material itself. The same goes for wood and metal structures upon which the double glazed window components will be installed in.

You should consider, too, how much your double glazed window installation will cost. Unfortunately, not many people have ever come across cheap double glazing! It can cost anywhere from the lower hundreds of dollars, to thousands of dollars, depending on how many windows you are replacing, and what added installation costs will be included, particularly if you’re adapting an existing window frame to allow for the use of a double glazed window pane system.

Budget options
double glazed windows 6
You might be thinking: that’s a lot of money! How can I even hope to upgrade to using this, if I can’t even muster the right budget for it?

Well, the nearest option is to apply for a home improvement loan at the bank, or apply for the equivalent loan version from the local government, particularly if the local or national government has an energy efficiency budget allocation for home improvement. These are sometimes called double glazing grants.

You should be aware, though, that when you do apply for home improvement loans, you will have to use materials or components (in this case the brand or quality of the double glazed windowpanes) that will be in the “approved” list of construction materials and products.

DO REMEMBER: the advantages of using double glazed windows may not be immediate in nature, but over time, you will probably end up saving so much more of your money, thanks to efficient heat insulation.


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