Want to save money on energy bills and increase your home’s comfort?
This is the question every homeowner struggles with when they need window replacement.
You know your old windows are bleeding you dry but you can’t decide which type of glass to use.
It’s a big decision that will affect your home for decades and the right glass can:
- Slash your energy bills by hundreds of dollars per year
- Make your home more comfortable
- Increase your home value
But here’s the problem:
Most homeowners have no idea what their options are. They make the wrong choice and miss out on huge savings.
The glass technology for windows has evolved significantly in recent years and choosing the right one for your home is critical. Whether you’re in need of emergency glass repair or you’re planning to renovate the whole house, this is the professional info you need to save yourself time, money, and headaches.
In this guide, you’ll learn:
- Single vs Double vs Triple Pane Glass
- Low-E Coatings That Work
- Smart Glass Options
- Cost vs Performance
Single Pane Glass
Single pane windows are pretty self-explanatory…
They have one single sheet of glass in the frame.
The problem: Single pane glass is the worst possible option from an energy-efficiency point of view, but they are the cheapest.
Single pane windows are a relic of the past and you’ll see them in older homes. They are energy vampires and you should do everything in your power to replace them ASAP.
There’s literally nothing blocking heat from going through them. Heat transfer through single pane windows is about as efficient as heat transfer in a vacuum.
In the winter, when you heat your home, your warm air is seeping right out through the window and in the summer, when it’s 100 degrees outside, that hot air is invading your home.
The Department of Energy says that heat gain through windows in the summer and heat loss through windows in the winter account for 25%–30% of residential heating and cooling energy use.
The simple fact is that if you’re living in a house that still has single pane windows you should replace them immediately. The savings in energy bills from upgrading to double or triple pane will pay for the upgrade in a few years.
Double Pane Glass
Double pane windows are by far the most popular choice for window replacement.
They have two sheets of glass with an air space in between. It’s typically filled with argon gas which is denser than air and helps insulate your home.
The insulating air space in double pane glass does several things:
- Blocks a lot of the heat transfer
- Eliminates or at least greatly reduces condensation issues
- Provides some noise reduction
- Available in every window style imaginable
Energy.gov has calculated that you can save between $101–$583 a year if you upgrade from single to double-pane glass.
But even though double pane glass has a massive advantage over single pane, it’s not without its drawbacks. Double pane is heavier than single pane and more expensive.
But these days, almost all building codes require double pane as a minimum standard.
Triple Pane Glass
If you’re looking for the best performance and energy efficiency, then go for triple pane.
Triple-pane windows are the Rolls-Royce of windows. It uses three sheets of glass and two air-filled spaces.
Insulation:
- Provides a greater R-value or level of resistance to heat flow
- Excellent sound dampening
- Less condensation
- Ideal if energy savings are your main concern
Triple pane windows are the absolute champions of energy efficiency. Studies show they’re the most energy-efficient window type available.
But of course, they’re also a lot more expensive and much heavier, so your existing window frame might need some reinforcing.
In most cases, the extra cost is not worth it given the relatively small additional energy savings you’ll get.
Low-E Glass Coatings
Low-emissivity (Low-E) coatings are the single most important glass upgrade you need to know about.
They’re invisible thin metallic coatings on the glass surface. They reflect infrared heat while allowing visible light to pass.
There are two main types:
- Hard coat Low-E glass
- Soft coat Low-E glass
Hard coat Low-E glass has the coating applied during the manufacturing process. It’s more durable but not quite as effective.
Soft coat Low-E glass has the coating applied after manufacturing and is more effective, but not quite as durable.
Industry data shows that you’ll pay about 10% to 15% more for windows with low-e coatings. But they reduce energy loss by up to 50% to 30%.
That’s a hard-to-beat return on investment!
The cool thing about Low-E coatings is that they can work in either direction, depending on the climate you’re in. In cold climates they help keep heat inside. In hot climates, they reflect heat away.
Smart Glass
Smart glass is the future and it’s here right now.
Smart glass is a type of window that can change its properties based on external conditions or user input.
There are a few types of smart glass:
- Electrochromic glass
- Thermochromic glass
- Photochromic glass
- Suspended particle device glass
Smart glass is super expensive right now, but the cost is dropping quickly. It’s something to consider if you’re building a new home or are doing a major renovation.
Gas Fills
The space between panes of glass isn’t empty air, by the way…
High-performance windows fill the gap between panes with special gas fills for better insulation.
The two most common are argon and krypton gas.
Argon gas is the default choice for most window manufacturers. It’s denser than air, non-toxic and colorless. It provides better insulation and is not too expensive.
Krypton gas is even better. It’s even denser and more insulating but more costly. Krypton is usually used with triple pane glass.
Both gases are completely safe and you won’t have any issues if a window breaks.
Which One Should I Choose?
Choosing the right glass type will come down to your climate, budget, and performance goals.
But here are the best options for most homeowners:
- Start with double pane windows with low-e coatings and argon gas fills. This combination gives you excellent performance for the price.
- If you’re in an extreme climate, go with triple pane glass.
- If you’re on a tight budget, use basic double pane but avoid single pane at all costs.
Don’t forget to look for the ENERGY STAR label, as well. Replacing old windows with ENERGY STAR certified windows can lower your household energy bills by an average of up to 13 percent nationwide.
Wrap Up
There you have it: The information you need to make the right choice for your home.
Remember that proper installation is just as important as choosing the right glass. You’ll need experienced professionals who know the importance of air sealing and proper techniques.
Your windows are a big investment in your home’s comfort and efficiency. Choose wisely and your windows will reward you for years with lower energy bills, increased comfort, and home value.
