R-value & Insulating Cellular Window Treatments


What is R-Value?

Prevent heat loss in your home with cellular shades!


Insulating cellular shades provide savings on heating and cooling costs

Did you know that 10-25% of your heating costs are wasted when heat leaks out of your windows? On average, it costs about $1,300 to heat an American home each year. If you do the math, that’s up to $325 going out your window! Energy-saving cellular shades control drafts to keep temperatures at a constant, so air conditioners and heaters aren't working so hard to keep the room regulated.

Understanding the Terminology of r-value.

You may have heard of it before, but haven’t understood what exactly it stands for. The R-Value is a measure of how well a material’s resistance is to heat flow and how well it resists heat gain or loss. Let’s make it simple, the higher the R-Value your material has the better insulation that you will receive.

R-Value & Your Windows

Your windows themselves have an R-value. A typical window has an R-value ranging from 0.9 to 3.0. To put this in perspective, the insulation that is used to build a home today has an R-value in the low 40s. Essentially, your window is a hole in the wall!

Take a look at this chart explaining how the R-Value of a given cellular shade corresponds to the type of window being covered.

  • Double Pane Window R- 1.8

  • Single Cell Light Filtering R- 1.6

  • Single Cell Black Out R- 2.5

  • Double Cell Light Filtering R- 2.8

  • Double Cell Light Filtering With Tracks R- 3.3

  • Double Cell Black Out R- 4.0

  • Double Cell Black Out With Tracks R- 4.7

R-value measures a material’s ability to resist energy transfer. The higher a material’s R-value, the better it insulates against heat or cold. A typical double-pane window has an R-value of 1.8. The R-value depicted beneath each type of cellular fabric represents the insulating properties of the shade alone, not combined with the R-value of the window it may be covering

Cellular Shade ProductShade OnlySingle Pane (+1)Double Pane (+1.8)TriplePane (+3.5)
cellularwindowshadesDouble Cell Light Filtering 2.8 3.8 4.6 6.3
cellularwindowshadesDouble Cell Light Filtering With Tracks 3.3 4.3 5.1 6.8
cellularwindowshadesDouble Cell Black Out 4.0 5.0 5.8 7.5
cellularwindowshadesDouble Cell Black Out With Tracks 4.7 5.7 6.5 8.2
cellularwindowshadesSingle Cell Light Filtering 1.6 2.6 3.4 5.1
cellularwindowshadesSingle Cell Black Out 2.5 3.5 4.3 6
*Single Cell Shades Aren't Available With Tracks
*All R-Value data provided by Comfortex

Why you should value R-value?

Quite simply, R-value measures how well a material reduces energy (heat) gain or loss. It’s a measure of thermal resistance, used most commonly in building and construction.

To put it in perspective, sprayed foam wall insulation has an R-value between R-14 and R-28, depending on how thickly it’s applied. Your windows have an R-value, too. Double pane glass is around R-1.8 – roughly 9% as resistant to heat transfer as your walls.

Understanding R-value allows you to shop wisely so you can decide on the most efficient and cost-effective household resources. The higher the R-value, the more energy you save. Energy saved is money saved!

So, about those windows…

Now that you’re an R-value pro, you might be thinking about how much less insulating your windows are than your actual walls. You might be imagining how up to 50% of your energy bill is flying out the window, or how your living room turns into an oven in the summer. But don’t give up hope! There are energy-saving solutions to these drafty sheets of glass we’ve grown to know and love.

Cellular window shades are designed with R-value in mind: the honeycomb-shaped fabric uses air pockets to slow the movement of thermal energy. Air happens to be a fantastic insulator (a 3/4” pocket of air has an R-value of .87!). Between the air pockets of the shade’s honeycomb cells and the insulating shade material itself, energy loss doesn’t stand a chance.

Energy is always trying to expand. In the winter, the warm air inside your home naturally moves toward and out your windows, so that it can expand into the cold, open air. In the summer, outdoor heat tries to make its way back inside your cooler home. Cellular window shades work as a barrier against both types of energy transfer, so you save year-round

Two of the most common types of insulating fabric are single cell and double cell, meaning there is either one row or two rows of insulating cells that make up the fabric portion of the shade.

You also have a choice between light filtering fabric and blackout fabric. Double cell light filtering cellular fabric allows natural light to pass through, but still maintains a nice, high R-value of 2.8. Double cell blackout fabric is lined with a thin, flexible foil that works to block out 99% of the sunlight and also amplifies the energy savings even more with an R-value of 4.0.

The final feature that makes our shades so energy efficient is the option to use energy-saving sidetracks alongside your cell shade. Sidetracks are plastic pieces that run the length of the window frame and intersect with the sides of the shade. They close the gap between the shade and the window frame, effectively “zipping up” your window for an even greater R-value. Sidetracks are available with all manual double cell shades.

Working the sun with insulating shades

Another energy-efficiency catchphrase you should get to know is Solar Heat Gain Coefficient (SHGC). This represents the amount of solar heat that is transmitted through a window.

We all love that solar heat gain streaming in during the winter. Free heat! But once summer rolls around, it’s better to leave all the solar gain to outdoor enthusiasts and plant life. Your house should be an escape from the heat, not a sweat lodge!

What’s awesome is that it’s really easy to maximize your SHGC in the winter and minimize it in the summer when you have insulating window shades.

In the summertime, cellular shades reduce the amount of heat that penetrates through windows so your cooling unit doesn’t work as hard to maintain a comfortable temperature. Blackout shades block virtually all of the sun’s rays, and light filtering shades help soften the sun’s impact. If you don’t mind leaving the windows covered throughout the day, you’ll feel a huge difference, and your air conditioning will require a lot less energy to keep things cool. At the very least, use your shades strategically by lowering when the window receives the most direct sunlight.

In the wintertime, let in as much sunlight as you can by leaving the windows that receive direct sunlight uncovered. Let that solar heat seep right in! Once the sun isn’t shining in, lower the shades to keep the heat inside. Cellular window shades act as a barrier that not only contains drafts but keeps heat from escaping outside. Your home will stay warmer longer.

The Department of Energy and the Environmental Protection Agency created the ENERGY STAR designation for products that meet high-performing energy efficiency criteria. If you’re interested in learning more about window criteria specific to your climate and location, you can start here!

Working with the sun

Energy Loss Through Thermal Images

Browse the images below to see the thermal loss. This particular scenario is during a cold night with room temperature around 68 degrees F.


These three images were taken in Vermont with a FLIR IR camera by the team at CellularWindowShades.com. You can see clearly that the glass temperature went from 28 degrees at 8 pm with no shade to 61.5 degrees with the shades down but no side tracks (9:13 pm) to 64 degrees with the shade down and with side tracks in place (9:16 pm). All of the shades in this these photos were taken using our double cell black out shades.

When the shade is down, it is sitting on the sill so it is interrupting the convection current which reduces heat loss. This kind of temperature gradient affects radiant and conductive heat loss. This amazing temperature difference will make the room more comfortable and will help save you on your energy bill because you will not be driven to raise the thermostat.

Cellular Shades Help Insulate in 3 Ways


Fight Convection

Seal gaps that may exist between the window and window frame, blocking the natural airflow and keeping warm air inside during winter and outside during summer.


Fight Conduction

Energy Smart Cellular Shades create an effective barrier between the glass window and your room, preventing heat transfer with the non-woven polyester fabric and double-honeycomb cell structure.


Fight Radiation

Light filtering and blackout cellular shades trap heat between the window and the closed shade, making your home comfortable and warm.


Add the Energy Saving Side Track System

Want to save even more on your monthly energy bill? Browse our energy saving side tracks which seal around your window.

Side tracks close the gap between the shade and the window frame, preventing even more energy loss!

These sidetracks will help you save an additional 20% on both your heating and cooling costs than shades without tracks. Energy Saving Side Tracks have been evaluated and verified by the Consortium for Advanced Residential Buildings (CARB).


Show me the Money

So, let’s say you suited your home with some incredible, energy-saving window shades. Ten years go by, and with just the shades alone, you’ve saved $5,000 on your energy bills. What are you gonna do with that money? Here are some ideas:

  • Take a cross-country road trip!
  • Install a nice big solar panel and save forever!
  • Order 300 large veggie pizzas!
  • Buy window shades for a few other houses!
  • Invest in a wild new invention! Or invent something yourself!
  • Just rest easy knowing you’re $5K richer by saving natural resources every day!

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