A simple experiment you can do at home to show how energy is lost from your home: on a cold day, place your bare hand on an external window. You’ll notice instantly the chill you feel, even if your home is heated to an adequate temperature. What this shows is that glass is an extremely good conductor of heat and that even if the rest of your home is energy efficient, your windows will be a weak point.
The single pane window is a major culprit of energy inefficiency in homes. In 1990, when single pane windows were the only real option for homes, over $20 billion in estimated energy costs were wasted in America every year. However, with the development in double pane technology, it’s now far easier to manufacture and fit double (or even triple) pane windows.
This guide will give you all the crucial information when it comes to double pane windows. Whether you’re building a new home, thinking about a renovation, or simply looking to be more energy-efficient, double pane windows are a solid choice for your home. This guide will show you how and why you can make it happen.
WHAT ARE DOUBLE PANE WINDOWS?
Windows are traditionally made up of two parts – the frame and the pane. The pane is the glass in the window. Although the glass helps you to see through, it also allows a great deal of heat to pass through. In the winter, heat from your home passes through the glass to the outside; in the summer, the heat from outside passes through the glass and heats up your home. Glass is simply too good a conductor of heat.
A double pane window solves this problem by sandwiching two pieces of glass together, leaving a small gap in between. It is the gap that provides the heat insulation. The gap is either filled with air, a special insulating gas, or all of the air is pumped out to make a vacuum.
Regardless of what is inside, the contents of the gap are poor conductors of heat. Although heat may travel through one of the layers of glass, it struggles to make the ‘jump’ to the second.
If you are ever in a home or office with double pane windows, repeat the touch experiment on a day when there’s a large temperature differential between inside and outside. In the winter, you’ll notice that the inner pane of glass is warmer. In the summer, you’ll notice it is cooler. However simple, this is the genius of a double pane window.
In addition to the insulation properties, double pane windows usually contain a desiccant (a substance that dries out the air), thereby ensuring that there is no condensation that forms either on the outside of the windows or in the gap. Condensation is formed when the air inside is rapidly cooled by coming into contact with the glass; since double pane windows are less dramatically colder than the air inside, this is less likely to take place.
WHAT ARE THE BENEFITS OF DOUBLE PANE WINDOWS?
As mentioned above, the primary function of double paned windows is the additional insulation that they bring. However, that has a lot of resulting consequences.
If you’re thinking about double paned windows, you should consider the following factors:
This is obviously the main benefit. Depending on the type of double pane window you choose, you can expect to save anywhere between 30% and 50% of the energy you would have otherwise lost through a single pane window.
Because of the way double pane windows reduce your energy usage, you can expect to save around 20% on your home energy bill for the year. This ballpark figure obviously has a lot of factors involved, but use this as a way to calculate whether double pane windows are feasible for you financially.
Determine 20% of your annual energy bill, and multiply by the number of years you expect to remain in your home. That gives you your budget for double pane windows.
SAVING THE ENVIRONMENT
Although this is a less tangible and less quantifiable benefit, it is arguably the most important one. By cutting down your energy wastage, you are burning less fossil fuels, which are a finite resource; you’ll also be reducing your own carbon footprint and greenhouse gas emissions.
One of the major secondary benefits of double pane windows is the way that they cut out exterior noise. The same gap that prevents heat transfer also provides heat insulation, both of which serve to keep your home free from energy wastage and exterior noise. If you live need a major road, or something else that causes a lot of undue noise, a double pane window is a great option.
WHAT ARE THE DOWNSIDES OF DOUBLE PANE WINDOWS?
The downsides to double pane windows are outweighed by the positives. As shown above, the ability to save money, keep your home warm, and to help the environment are all major benefits. However, there is a reason why not every home currently has double pane windows.
If you are thinking of making the switch, you should consider the following:
The major reason why homes don’t have double pane windows as standard is the cost of installation. For more information on double pane windows, see our guide Average Cost of Double Pane Windows. What you’ll see is that the average cost of one double pane window is between $385 and $850, which obviously represents a major investment. The cost can also be prohibitive because of the issue of installation.
Can't install just one
Installing one double pane window is not an efficient use of money, as the older, single pane windows that remain will still leak heat in the same way. Instead, you’ll need to install multiple windows at once. Completing one whole floor of windows is usually a minimum to see any benefit (assuming that you can’t convert all your windows at once). This means that the capital outlay at the start is usually measured in the thousands (or tens of thousands), not the hundreds.
Differences in quality
There is always the temptation to save money by cutting corners. However, this represents a false economy when it comes to double pane windows. Choosing windows of a poorer quality leads to problems like failed seals, improperly spaced glass, and general problems with the glass quality. All of this serves only to undermine the whole point of buying double pane windows in the first place. You don’t want to spend money on repairing your double pane window. Instead, you’ll need to spend the money to ensure you get the quality.
PRICING AND INSTALLATION CHECKLIST
If you’re ready to take the plunge and buy double pane windows, you should be prepared to put in the work and get the perfect option for you. While this may seem daunting, it doesn’t need to be.
You should aim to get a few different estimates before you decide the right option for you. Don’t be fooled into paying for an estimate – these are usually free. Give the company as much information as possible so you can get a detailed quote. Ask for them to email it to you so you have it in writing. Aim to get quotes in late Fall or early Winter, which is contractors’ quiet season.
Don’t choose exclusively based on price
When you are selecting which company you’d like to work with, don’t automatically go with the cheapest – or the most expensive. Prices fluctuate when it comes to windows, so the actual cost of the windows gets lost in the overhead and operational costs. A high price doesn’t guarantee poor quality work, and nor does a low price denote poor quality.
Create an emergency budget
When getting and agreeing on a price, factor in 7% to 15% more than the price you agreed. This will allow you to cover any unexpected issues that emerge. For example, if you are quoted $5,000, you should ensure you’d be comfortable spending $5,750. Don’t agree to an initial quote that is right at your desired budget – it’s better to wait a year and boost your savings.
If you live in a cold climate
you should absolutely be thinking of upgrading to double pane windows. Double pane vinyl or wood-framed windows reduce energy usage by as much as 24%.
If you live in a warm climate
you can expect to use 18% less energy in the summer – making a major difference to your overall energy bill.
Although there is an upfront cost when it comes to installing double pane windows, these costs are recouped by a reduction in energy usage (which you will start to notice immediately) as well as an overall increase in the overall value of your home.