DOUBLE VS. TRIPLE
Forty years ago, almost every home in the United States had single pane windows. Although many homes still do, they are increasingly being replaced with more updated versions with more panes. There are double pane windows in around 68.5 million US homes. Around 1.2 million have triple pane windows. These numbers continue to grow, as more and more consumers are environmentally- and cost-conscious.
Furthermore, many local governments are offering subsidies to encourage homeowners to switch to more energy-efficient homes. In a not-too-distant future, the single pane home will be a relic from the past, like a home without electricity.
So if you live in a single pane household home, this guide will get you up to speed on what you’re missing out on. It may be that the time is right for you to bring your home into the twenty-first century, and to do some good for the environment and your wallet.
WHAT ARE DOUBLE AND TRIPLE PANED WINDOWS?
The pane of a window refers to the glass inside the frame. For most of human history, all windows were single paned, meaning there was only one layer of glass inside the frame. Glass was extremely expensive and tricky to manufacture, which meant that anything more than a single pane simply wasn’t possible.
However, as glass-making technology improved, it became easier to make panes of glass, and therefore double or triple panes became attainable for most households. Most houses still have single paned windows although it is increasingly common in newer builds to install double pane windows.
A double pane window – sometimes known as a double glazed window – contains two sheets of glass with a small gap in between. In this space is either air, special insulating gas, or, in some circumstances, a vacuum.
The gap between the windows is what makes the windows especially energy-efficient. Heat cannot easily pass across the gap between the two panes, which means that the windows are especially good at preventing a house from losing heat in the winter or gaining it in the summer. As windows are one of the biggest ways a house loses and gains heat, installing double pane windows helps greatly to mitigate energy loss.
A triple pane window takes everything to the next level. Adding an extra pane of glass allows for another gap between panes, meaning that there are now two gaps that heat must pass through.
These serve to increase the energy efficiency by somewhere around fifty percent compared with double pane windows. Most of the time, the gaps in triple pane windows are filled with gas, which means that they are even better as insulators.
Naturally, there are major price differences, both within each bracket (different brands, styles, and designs result in different total costs) as well as between double and triple pane. For more information on this, see the section below comparing prices, or our article Average Cost of Double Pane Windows.
WHAT ARE THE
R VALUE AND
The two key metrics that are used in measuring energy efficiency – and therefore extremely relevant when it comes to looking at double and triple pane windows – are the R value and the U value. Understanding what they refer to will help you a great deal when deciding which options are right for you.
The R value – sometimes known as the ‘R factor’ – is a figure used to measure the amount of heat resistance in a material (a window in this instance). A double pane window will likely have an R value of somewhere between 3 and 4 (the higher the value, the better). A triple pane window can have an R value of up to 9 or 10.
The U value – also known as the ‘U factor’- refers to how much heat transference happens through a material. The U value of the wall of a home is around 0.3 U (the lower the U value, the better the insulation). A double pane window has a U value of around 1.4, whereas a triple pane window can be as low as 0.5 – almost as effective as a wall at retaining heat.
These two figures are obviously related, but what both allow is an easy to quantify way different types of windows and how they will affect the energy efficiency in your home. What you’re looking for is the lowest possible U value and the highest possible R value.
One way to think about the difference between the two is that the U value is a measure of how much heat stays in your home (i.e. an important figure for those who live in colder climates, or areas with cold winters); the R value is a measure of how well your home can resist heat (i.e. a key metric if you live in a climate capable of great heat.
WHAT ARE THE PRICE DIFFERENCES BETWEEN THE TWO?
THE OVERALL COST
On average, a triple pane window will cost between 10% and 25% more than a double pane window. On a one-off window, this may seem like a marginal difference. However, over the course of an entire house renovation, the price difference can run well into the thousands.
The price for one double pane window is usually somewhere between $385 and $850.
Window brand choice
Type of window
Window framing materials
This means that you’ll likely pay somewhere between $500 and $1,000 for one double pane window. Getting more done reduces the per-window cost. From these figures, we can calculate that a triple pane window is likely to be between $550 and $1,250. These figures are intended as ballpark numbers, as prices vary a great deal across the country and depending on the design and style of windows you select.
A further factor to consider is the differential in savings. Generally, triple pane windows are 50% more effective at conserving energy, which translates into a saving of between 2% and 5% per year on your energy bill.
For example, the average American spends $650 per year heating their home. If a double pane window saves around 20% on an energy bill, that equates to a saving of $130 per year.
A triple pane window will save around $150 per year. If you intend to stay in your home for 10 years, you can multiply these figures by 10, to give you $1,300 for double pane and $1,500 for triple pane.
All of these figures can be tweaked based on your own personal circumstances but should help you to calculate the financial considerations involved.
SHOULD I GET DOUBLE OR TRIPLE PANE WINDOWS?
Assuming you’ve decided to make the upgrade from single pane windows, the question is really whether you should get double or triple panes to replace them. The above information (particularly the pricing) should be a critical factor in your decision-making, although it’s worth considering the following pros and cons of triple panes:
Advantages of triple pane windows
Limitations of triple pane windows
Either way, if you’re thinking about double versus triple pane, you’re asking the right questions. You’ll need to get quotes for your specific circumstances and work out the financial implications of both options before you make your decision. We can also help if you ever need double pane window repair.
So, if you’re one of the 48.5 million households in America that still has single pane windows, it may well be that it’s time to make the switch. Admittedly there can be a fairly hefty capital outlay. However, you will earn this back over time. You can measure this clearly by seeing the reduction in your energy bills. You’ll also see a boost to your house price, although this can be harder to measure directly.