A Beginner’s Guide to Thermal Windows: Types, Pros, and Cons

A thermal window is a broad term encompassing many energy-efficient window products, all with the same goal – to stop heat transfer.

Basic thermal windows are a standard, but there are also specialty upgrades you can choose from. If you want the most bang for your buck, here’s what to know about thermal windows.

What is a Thermal Window?

Thermal windows

Thermal windows stop heat transfer. In the winter, they prevent heat from escaping the home. In the summer, they prevent outside heat from entering the house.

How well a thermal pane window prevents heat transfer depends on several things, including how many panes the window has, the filling between the glass panes, and special coatings.

Types of Thermal Windows

One thing all thermal windows have in common is at least two glass panes. Thermal windows are insulated glass units or IGUs. An IGU is a glass unit with multiple panes and a tight seal. 

Here are the different types of thermal windows:

  • Double pane windows – These windows have two pieces of glass separated by a spacer and filled with air or a non-toxic insulating gas.
  • Triple pane windows – Triple pane windows feature three sheets of glass separated by spaces. The space between the glass panes contains an air or dense, non-toxic gas filling.
  • Air-filled windows – An air-filled window refers to a double or triple pane window with air between the panes of glass, acting as an insulator. 
  • Argon-filled windows – Argon is a non-toxic gas, six times denser than air, acting as an insulator and preventing heat transfer. Argon is the most common gas used as an insulator in windows and the least expensive.
  • Krypton-filled windows – Krypton is a non-toxic gas, six times denser than Argon. While it prevents even more heat transfer, it’s also more expensive.
  • Low-E Coating – Low-E is a microscope coating put on glass. It stands for low emissivity and reflects heat back into the home. A special type called Solar Low-E can reflect heat from the outside, preventing it from entering the house.

How Much Are Thermal Windows?

The average double pane thermal window price is $600, ranging from $200-$1,200 depending on the brand, material, and glass. For example, a window featuring a wood window frame, a krypton gas filling, and Low-E coating will be on the higher end, while a vinyl window with Argon or air filling will be much less expensive.

On average, when compared to apples-to-apples, a triple-pane window will run 10-20% more than a double-pane window.

What are the Benefits of Thermal Windows?

Thermal windows help eliminate heat transference, keep your house more comfortable, and save you money on energy bills. 

Here’s a look at the most significant benefits of thermal windows:

  • Stop heat transference – These windows help to keep warm air inside during the winter and warm air outside during the summer.
  • Energy savings – Better regulated temperatures equal more savings on your energy bill.
  • Customizable – You can customize a thermal window based on your budget, climate, and personal needs.

What are the Problems with Thermal Windows?

One problem with thermal windows is that you can’t repair the glass. So if the glass on your thermal window breaks or the seal loosens, you need to replace the entire insulated glass unit. 

The tight seal on thermal windows makes them energy efficient but also prevents them from being easily repaired. 

Is There a Difference Between a Thermal Window and a Double-Pane Window?

A double-pane window is a type of thermal window. Even an air-filled, basic double-pane window works to stop some heat transference. Double-pane windows with argon or krypton gas fillings and low-emissivity coatings will be the most energy efficient.

Why Would a Thermal Window Fog Up?

It’s not uncommon to see the external glass on a thermal window fog up in the winter when the house is hot inside and cold outside. But, if you notice your thermal window fogging up between the panes, the seal is broken, and you need to replace the entire insulated glass unit.

How Long Do Thermal Windows Last?

Expect your thermal window to last 10-25 years, depending on the quality and your climate. Thermal windows last longer in mild climates than they do in extreme ones. The brand and quality of the window are also contributing factors to lifespan.

How Do You Clean a Thermal Window?

Thermal windows feature glass, which means you can use any glass cleaner and a lint-free cloth for cleaning. If your thermal window has a Low-E coating, avoid cleaners that have ammonia or other harsh chemicals.

Frequently Asked Questions (FAQ)FAQ

What does windows with a thermal break mean?

A thermal break is a spacer or piece of material inside a window frame that stops heat transference. Aluminum frames are the primary type of window with thermal breaks.

Can you reseal thermal windows?

You can’t reseal thermal windows. Thermal windows contain IGUs, or insulated glass units, that feature two or more panes of glass with a spacer, insulating filler, and a tight seal. Once the seal weakens or breaks, you must replace the entire IGU.

Are thermal windows hurricane-proof?

Not all thermal windows are hurricane-proof, but some are. You can find impact-resistant thermal windows from most top window manufacturers.

Will new thermal windows help with heat?

New thermal windows can help with heat as long as your home is well-insulated. Thermal windows stop heat transference – this means they keep heat in during the winter and prevent it from entering the house during the summer. How well your thermal window prevents heat transference depends on the type you choose.

Are all double-pane windows insulated?

All double-pane windows are insulated to a certain degree. Air-filled double-pane windows have the least insulative properties, while argon and krypton-filled windows offer better insulation.

Are triple-pane windows thermal windows?

All triple-pane windows are a type of thermal window. Even air-filled triple pane windows act as an insulator and stop heat transference.

Final Thoughts

A thermal window is a broad term for a window that reduces heat transference. A few types of thermal windows are double-pane, triple-pane, gas-filled, and Low-E glass windows. The specific type of thermal window you need depends on your climate and your windows’ direction.

All window manufacturers offer thermal products to a certain degree. So if you’re in the market for windows, you shouldn’t have a problem finding a good thermal window that will regulate temperatures in your home.