Best Insulated Window Coverings & R-Value of Windows
What is R-value of windows?
R-value refers to the resistance of windows to heat conduction. R-value of a window shade is inversely proportional to the room temperature. Selecting a shade with higher R-value results in keeping the room cold when the sun is burning outside. A shade of higher R-value helps in reducing the energy bills. Higher the R-value, higher the resistance to heat flow through the window.
Ecosmart Insulating Cellular Shades
What is meant by insulation?
Insulation is an act of protecting something by surrounding it with material that reduces or prevents the transmission of sound or heat. Insulating Cellular Shades performs this act and make your home warm during winters and cold during the summers. Insulating cellular shades provide a great effect on reducing your energy bills by keeping your home safe from the extreme weather conditions. Even when the weather is too cold or hot outside, these insulating cellular shades keep the room more comfortable for you by resisting the outside weather and maintaining room temperature.
Energy Efficiency of Double Cellular Shades
Double cellular shades offer more insulation value than a single cell. As they contain double pockets than that of single shades these exhibit double efficiency than the single cellular shades. If you are looking for energy efficient shades, then double cellular shades are a perfect choice. These shades consist of pleated pockets that allow the air and use this air as a barrier to block the outside temperature and keeps the home more comfortable.
Sun Tempered Super-Insulated Homes
According to the Colorado State University Extension, an average American household uses 38% of its total annual energy on heating. To conserve energy at home it suggests building Sun Tempered Super Insulated homes that use passive solar design concepts with super insulation construction techniques. A cold but sunny climate is better suited for this purpose. The primary objective is to use the sun’s heat to warm spaces during the day. While this heat cannot be stored and gets released overnight, the super-insulated shell makes solar tempering work at all times.
This practice includes solar orientation – orient most household activities and work areas as well as windows to the south. Increased insulation levels are used in wall, ceiling and foundation walls. Effective air/vapor barrier controlled ventilation and energy efficient window treatments. This energy efficient construction can save 75% of annual energy costs for heating and cooling compared to a standard home and is more comfortable and healthy for its occupants.
Sun tempered super-insulated homes are now included in the Canada Building codes too. Programs like the Energy Star Housing program sponsored by the Environmental Protection Agency and the Department of Energy encourages builders to build super-insulated homes and provide a rating system to evaluate energy performance.
Energy Efficient Window Treatments
Energy efficient homes are built carefully with thicker walls and higher insulation levels to reduce energy usage for heating and cooling purposes. However, windows form the weak link in energy efficiency. They are typically only 18% of the overall house but account for 50% of a home’s energy loss. The amount of energy lost is proportional to the size and some windows. Energy efficient window treatments then come to the rescue. Energy efficient window treatments help in cutting down heat loss from our homes in winters. They act as good insulators slowing down the escape of warm air and increase a home’s comfort levels.
In summers, they cut infiltration of warm air into our homes that are the single largest contribution to the workload of our home’s cooling systems. The energy efficiency of a window treatment will speak for itself when the year-round savings on heating and cooling costs are considered. The more heat loss and heat gain controlled the more the money saved on keeping spaces warmer in winter and cooler in summer. Simple numeric values for products and fabric types can help one gauge the energy efficiency of any window covering. The R-value or the thermal conductivity is one such indicator.
Thermal conductivity or the R-value
As described earlier, a product’s R-value is a measurement of its ability to resist heat flow during the winter. It indicates the ability of walls, roofs, and windows to keep heat inside.
It depends on the type of insulation material, its density, and thickness.
The higher the R-value, the more insulation a product provides.
The wall and roof of a well-constructed home typically have an average value of 25. A single layer of uncovered glass window has an R-value of 1.75. A Low-E double glazed window can have an R-value of 3.5. Such low values of thermal conductivity indicate why these windows can allow seven to ten times more heat to escape per sq. foot than the rest of the exterior. Truly, windows can be “energy holes”.
This is how a right window treatment gives a positive impact.
A fully recessed honeycomb cellular opaque shade adds on average, 3.56 to the R-values of Low-E windows. The shades double the efficiency of the R-3.5 windows and reduce heat loss through them by 50%.
A standard Aluminum blind in a double glazed window carries an R-value of 2.32. A single cellular shade on that same window creates an R-value between 3.5 and 4.3. But a double or triple honeycomb cellular shade creates an R-value of 4.8. This is a substantial saving on energy costs.
If the Total R-value of a window space is considered, it is the sum of all the layers of material, from the inner blinds, through the window and out of the window film, if any. Even the air trapped between the layers of window dressings contribute to its total R-value.
When calculating the R-value of a multi-layered installation, add the R-values of the individual layers.
R-value of window treatments
All window treatments are not created equally considering R-values and energy savings. Typical Horizontal blinds have an average R-value of 2.5 while honeycomb shades are better insulators and have an R-value of 3.25 to 5. By increasing the R-value of a window covering one can decrease on energy bills.
Some window coverings in the approximate order of ability to resist heat flow –
- Insulated Roman Shades 2.5-7.0 depending on the number of layers
- Double Cell Blackout Shades 4-6
- Double Light Filtering Shades 2.1-3.6
- Shutters 3.4
- Vertical Blinds 3
- Aluminum blinds 2.8
The above values are accorded for blinds, shades, and shutters in a closed position.
While standard blinds and curtains have an R-value of just 1, energy saving window coverings with an insulation layer, like the honeycomb shades and curtains with thermal linings can have an R-value of 6.
Low R-value of Shutters and Blinds
Hardwood shutters with adjustable louvers or wooden blinds have much lower insulation values because of the gaps between the louvers or slats that let considerable air flow through while shutters with foam cores and paneling have insulating values of 3.2. The energy efficiency of foam cored shutters again depends on the snugness of the fit between the shutter edges and window and on the thickness and type of insulating foam used in the shutter.
Graber Cellular Shades for Maximum Efficiency
Graber’s CrystalPleat Cellular shades are a stylish way to boost the energy efficiency of a home. An attractive closed honeycomb cell design creates pockets of air that insulate windows from heat and cold to lower energy bills year round.
These Insulating Cellular Shades are customizable with four opacity levels and three cell sizes:
- 3/8” Double Cell
- 3/8” Single Cell
- 3/4” Single Cell
The two primary factors that influence a shades ability to resist heat transfer are material thickness and airspace.
Material thickness Airspace–
- 3/8” Single Cell .024”-.026” .56 cubic inch per inch width
- 3/4” Single Cell .024”-.026” 1 cubic inch per inch width
- 3/8” Double Cell .036”-.039” .72 cubic inch per inch width
Based on independent tests, Graber CrystalPleat Cellular Shades are proven to be energy efficient. All Graber CrystalPleat fabrics perform well with only a slight difference in % reduction of transfer between R-values.
Type of fabric R-value % Reduction of heat transfer
- Cocoon Double Cell 4.76 22%
- Solitude Single Cell 4.55 21%
- Elegant Neutrals Single Cell 4.55 21%
- Cocoon Single Cell 4.55 21%
- Translucence Double Cell 4.55 21%
- Garden Retreat Single Cell 4.55 20%
- Crinkle Single Cell 4.55 19%
- Translucence Single cell 4.55 19%
Recommended brands for winter time energy efficient window treatments on ZebraBlinds.ca are –
- Graber CrystalPleat Light Filtering Single Cellular Shades
- Graber CrystalPleat Light Filtering Double Cellular Shades
- Graber CrystalPleat Blackout Double Cellular Shades
Some window treatments are more energy efficient than others, so be sure to check their R-values.