5 Things to Know Before Buying Surface Facade Light price

Community Identity: Facade lighting can convey a sense of identity and pride within a community. It fosters a sense of belonging and ownership among residents, who take pride in the illuminated beauty of their neighborhoods.

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Navigation and Wayfinding: In urban areas, facade lighting aids navigation by providing visual cues and landmarks. It helps pedestrians and drivers orient themselves within the cityscape, making it easier to find their way around.

Cultural and Historical Preservation: Facade lighting plays a crucial role in preserving buildings cultural and historical heritage. It enables the careful illumination of historical structures, museums, and heritage sites, allowing them to be appreciated even after dark. This preservation of cultural identity is essential for passing down heritage to future generations.

They are creating Landmarks: Iconic buildings and landmarks often owe their recognition to distinctive facade lighting. Illuminating landmarks makes them more visible and reinforces their significance within a city or region. These landmarks become symbols that instill pride in the community and attract tourists.

Enhancing Aesthetics: One of the primary roles of facade lighting is to improve the visual appeal of buildings and structures. It highlights architectural details, textures, and unique design elements, transforming them into mesmerizing nighttime spectacles. Well-designed lighting can breathe new life into even the most ordinary structures, making them stand out and contributing to the overall beauty of a location.

Facade lighting, often considered a subtle yet powerful art form, holds paramount significance in architecture, urban design, and cityscapes. Thoughtfully planned facade lighting designs have the potential to accentuate the prominent characteristics of a building. It transcends the conventional idea of illumination to become a cornerstone in creating visually compelling and dynamic environments.

In recent years, you may have found that the halogen bulb you've been buying for years is no longer available at your local hardware store. That's because LED spotlights are quickly being introduced to the market as a more energy efficient alternative.

With the transition to LED technology, a lot of the metrics and points to consider are now different. If this is your first time purchase of LED spotlights, you might be worried, confused or frustrated.

Not to worry! After reading our 4-point guide below, you'll be able to make a confident and educated LED spotlight purchase in no time.

 

Consideration #1: Size & form factor

First and foremost, you will want to narrow down your LED spotlight search by determining what mechanical size and shape of bulb you will need.

Generally speaking, there are three types of LED spotlights: MR, BR and PAR. The type name is typically followed by a two digit number, which indicates the bulb diameter in 1/8ths of an inch.

MR16

MR16 bulbs are the smallest type of spotlight with a 2 inch diameter. These bulbs are typically used for lower brightness applications. LED spotlights of this size are typically 5-8 Watts.

MR16 bulbs come in two variants that differ in base type (how the bulb is mounted into the socket).

If you see a narrow, two-pin connector without rounded bottoms as shown in the photo below, you have a GU 5.3 version. These are almost always very low voltage (12V AC or DC).

In recent years, you may have found that the halogen bulb you've been buying for years is no longer available at your local hardware store. That's because LED spotlights are quickly being introduced to the market as a more energy efficient alternative.With the transition to LED technology, a lot of the metrics and points to consider are now different. If this is your first time purchase of LED spotlights, you might be worried, confused or frustrated.Not to worry! After reading our 4-point guide below, you'll be able to make a confident and educated LED spotlight purchase in no time.First and foremost, you will want to narrow down your LED spotlight search by determining what mechanical size and shape of bulb you will need.Generally speaking, there are three types of LED spotlights: MR, BR and PAR. The type name is typically followed by a two digit number, which indicates the bulb diameter in 1/8ths of an inch.MR16MR16 bulbs are the smallest type of spotlight with a 2 inch diameter. These bulbs are typically used for lower brightness applications. LED spotlights of this size are typically 5-8 Watts.MR16 bulbs come in two variants that differ in base type (how the bulb is mounted into the socket).If you see a narrow, two-pin connector without rounded bottoms as shown in the photo below, you have a GU 5.3 version. These are almost always very low voltage (12V AC or DC).

If you see a broader 2-prong connector with rounded bottoms as shown in the photo below, you have a GU 10 version. These are almost always mains voltage (120/240V AC).

If you see a broader 2-prong connector with rounded bottoms as shown in the photo below, you have a GU 10 version. These are almost always mains voltage (120/240V AC).

!Protip: you may sometimes find that certain manufacturers refer to MR16 bulbs with GU 5.3 bases as simply [MR16] (without the base designation) and MR16 GU10 bulbs as [GU10] bulbs. This is not technically correct but you may want to be aware of this when you are reviewing product specifications.

PAR20

The next size up is a PAR20 bulb, which is 2.5 inches in diameter. PAR20 bulbs are common in residential applications in smaller homes or where ceilings are not as tall. LED spotlights of this size are typically 13 Watts.

The vast majority of PAR20 bulbs use the same E26 Edison screw base that standard A19 bulbs use, and operate on mains voltage (120/240V AC).

!Protip: you may sometimes find that certain manufacturers refer to MR16 bulbs with GU 5.3 bases as simply [MR16] (without the base designation) and MR16 GU10 bulbs as [GU10] bulbs. This is not technically correct but you may want to be aware of this when you are reviewing product specifications.PAR20The next size up is a PAR20 bulb, which is 2.5 inches in diameter. PAR20 bulbs are common in residential applications in smaller homes or where ceilings are not as tall. LED spotlights of this size are typically 13 Watts.The vast majority of PAR20 bulbs use the same E26 Edison screw base that standard A19 bulbs use, and operate on mains voltage (120/240V AC).

PAR30

PAR30 bulbs are similar in shape and function to PAR20 bulbs, but are quite a bit larger at 3.75 inches in diameter. These are commonly used in higher ceiling applications. LED spotlights of this size are typically 15 Watts.

PAR30PAR30 bulbs are similar in shape and function to PAR20 bulbs, but are quite a bit larger at 3.75 inches in diameter. These are commonly used in higher ceiling applications. LED spotlights of this size are typically 15 Watts.

PAR38

The largest of the commonly used residential spotlight sizes is the PAR38. At 4.13 inches in diameter, these are large and bright, rated at upwards of 100W for halogen bulbs. LED spotlights of this size are typically 18 Watts.

PAR38The largest of the commonly used residential spotlight sizes is the PAR38. At 4.13 inches in diameter, these are large and bright, rated at upwards of 100W for halogen bulbs. LED spotlights of this size are typically 18 Watts.

Now that we've gone over the bulb types, how do you know which one to choose? The short answer is: follow the directions on the lampholder.

If you take a look at any reputable lamp fixture, you should see a sticker or imprint noting the type of bulb size that is compatible.

Now that we've gone over the bulb types, how do you know which one to choose? The short answer is: follow the directions on the lampholder.If you take a look at any reputable lamp fixture, you should see a sticker or imprint noting the type of bulb size that is compatible.

In this example, the lampholder says "USE PAR20 TYPE" so we know for certain that this is the type of LED spotlight that is needed.

Consideration #2: Color - CCT and CRI

With halogen spotlights, color was never an option - pretty much all products from all manufacturers had the same color temperature and color quality.

With LED spotlights, however, many color temperature and CRI options exist, making it more difficult to ensure that you pick the right one for your needs.

Color temperature: pick K LED spotlights

Color temperature is a number that describes how "yellow" or "blue" a light's color is.

• K is considered the same color as the classic incandescent light bulb


• K is slightly bluer and is similar to halogen bulb light color, but still has a warm, inviting yellow color to it.


• K is often called "neutral white" because it is neither blue nor yellow - and is the middle of the color temperature scale.


• Anything over K will appear blue-ish and would not be recommended for standard residential applications.

 

In this example, the lampholder says "USE PAR20 TYPE" so we know for certain that this is the type of LED spotlight that is needed.With halogen spotlights, color was never an option - pretty much all products from all manufacturers had the same color temperature and color quality.With LED spotlights, however, many color temperature and CRI options exist, making it more difficult to ensure that you pick the right one for your needs.Color temperature: pick K LED spotlightsColor temperature is a number that describes how "yellow" or "blue" a light's color is.

Lighting for your home is ultimately a personal choice, but we recommend starting with K LED spotlights to test. If you think it's too yellow, you can switch to K or K. If you think it's too blue, you can switch to K.

Most of these color temperatures are readily available from most manufacturers.

CRI: pick 80 or above

CRI is a bit tricky to understand because it is not immediately visible from just simply looking at an LED spotlight.

CRI is score ranging from 0 to 100 which measures how accurate objects appear under a light. The higher the score, the more accurate.

What does accurate really mean, anyway?

Let's say you are trying to light up a painting. An perfectly accurate LED spotlight would make the painting look exactly the same as it does under a halogen bulb.

An inaccurate (low CRI) LED spotlight, however, would make the painting look "off" - the colors might appear mismatched, washed out, or indistinguishable.

Lighting for your home is ultimately a personal choice, but wto test. If you think it's too yellow, you can switch to K or K. If you think it's too blue, you can switch to K.Most of these color temperatures are readily available from most manufacturers.CRI: pick 80 or aboveCRI is a bit tricky to understand because it is not immediately visible from just simply looking at an LED spotlight.CRI is score ranging from 0 to 100 which measures how accurate objects appear under a light. The higher the score, the more accurate.What does accurate really mean, anyway?Let's say you are trying to light up a painting. An perfectly accurate LED spotlight would make the painting look exactly the same as it does under a halogen bulb.An inaccurate (low CRI) LED spotlight, however, would make the painting look "off" - the colors might appear mismatched, washed out, or indistinguishable.

This is not limited to paintings or artwork. The appearance of furniture or food can also appear to be lacking in color and dull, if the LED spotlight has insufficient CRI.

Well, what is a sufficient CRI number?

• We recommend purchasing LED spotlights with a minimum of 80 CRI.


• For enhanced appearance, we recommend 90 CRI or above.

How do you know what an LED spotlight's CCT or CRI is? Virtually all manufacturers will be able to providethis to you on the product specification sheet or packaging.

This is not limited to paintings or artwork. The appearance of furniture or food can also appear to be lacking in color and dull, if the LED spotlight has insufficient CRI.Well, what is a sufficient CRI number?How do you know what an LED spotlight's CCT or CRI is? Virtually all manufacturers will be able to providethis to you on the product specification sheet or packaging.

Consideration #3: power and brightness

You are likely used to thinking of bulb brightness in terms of watts - a 60 watt bulb is brighter than a 40 watt bulb.

But don't forget that watts are a measure of electrical energy in, not necessarily the total light output.

This was an acceptable way to estimate brightness because most halogen bulbs have the same amount of efficiency.

LED spotlights are far more efficient than halogen bulbs. What this means is that watts is no longer a useful measure of brightness.

You are likely used to thinking of bulb brightness in terms of watts - a 60 watt bulb is brighter than a 40 watt bulb.But don't forget that watts are a measure of electrical energy in, not necessarily the total light output.This was an acceptable way to estimate brightness because most halogen bulbs have the same amount of efficiency.LED spotlights are far more efficient than halogen bulbs. What this means is that watts is no longer a useful measure of brightness.

...use much more energy (in watts) than...

...use much more energy (in watts) than...

to generate the same amount of light output.

Instead of focusing on watts in, you will need to focus on the light output, which is measured using the lumens metric.

Not sure how many lumens you need? You can estimate what you need based on what you had installed before switching to LEDs.

This can be calculated using a simple formula:

Lumens = [watts in halogen] x 15

For example, if you had a 40W halogen bulb, you can can estimate the number of lumens by multiplying 40 by 15 = 600 lumens.

You will find the number of lumens listed alongside the product specifications.

 

to generate the same amount of light output.Instead of focusing on watts in, you will need to focus on the light output, which is measured using themetric.Not sure how many lumens you need? You can estimate what you need based on what you had installed before switching to LEDs.This can be calculated using a simple formula:Lumens = [watts in halogen] x 15For example, if you had a 40W halogen bulb, you can can estimate the number of lumens by multiplying 40 by 15 = 600 lumens.You will find the number of lumens listed alongside the product specifications.

Consideration #4: beam angle

Finally, you will want to consider the shape of light that comes out of the LED spotlight.

The shape is described as beam angle. Beam angle is defined as the angle in which 50% or more of the light is distributed.

Finally, you will want to consider the shape of light that comes out of the LED spotlight.The shape is described as beam angle. Beam angle is defined as the angle in which 50% or more of the light is distributed.

If you have a narrow beam angle, you will be concentrating the light into a smaller area, thereby increasing the amount of light that shines in that area.

If you have a wide beam angle, the light will be more dispersed. You will be able to illuminate a wider area, but you will be "diluting" the light across a larger area, effectively reducing the amount of illumination on that surface.

Also keep in mind the cone shaped light distribution of LED spotlights. As you increase the distance from the lamp, the dispersion increases as well.

This means that if you have high ceilings, you will want to make sure you select a narrow beam angle LED spotlight to ensure that the light can "reach" before dispersing.

Other considerations

We hope you found our recommendations helpful. Ultimately, lighting is oftentimes a personal and aesthetic choice, and the best test is a visual test.

If you have a relatively large project, it is probably a good idea to purchase one or two LED spotlights first to test and make sure that the color and brightness are what you expect.

If it looks okay, then you can proceed with purchasing the rest!

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If you have a narrow beam angle, you will be concentrating the light into a smaller area, thereby increasing the amount of light that shines in that area.If you have a wide beam angle, the light will be more dispersed. You will be able to illuminate a wider area, but you will be "diluting" the light across a larger area, effectively reducing the amount of illumination on that surface.Also keep in mind the cone shaped light distribution of LED spotlights. As you increase the distance from the lamp, the dispersion increases as well.This means that if you have high ceilings, you will want to make sure you select a narrow beam angle LED spotlight to ensure that the light can "reach" before dispersing.We hope you found our recommendations helpful. Ultimately, lighting is oftentimes a personal and aesthetic choice, and the best test is a visual test.If you have a relatively large project, it is probably a good idea to purchase one or two LED spotlights first to test and make sure that the color and brightness are what you expect.If it looks okay, then you can proceed with purchasing the rest!

A-Series LED Bulbs

Our A19 and A21 lamps fit in standard lamp fixtures and are perfect for floor and desk lamp fixtures.

Candelabra LED Bulbs

Our candelabra LED bulbs offer soft and warm light output in a decorative bulb style that fits E12 lamp fixtures.

BR30 LED Lamps

BR30 lamps are ceiling lamps that fit in residential and commercial fixtures with 4-inch or wider openings.

T8 LED Lamps

Directly replace 4-ft fluorescent lamps with our T8 LED tube lights, compatible both with and without ballasts.

Contact us to discuss your requirements of Surface Facade Light price. Our experienced sales team can help you identify the options that best suit your needs.

LED-Ready T8 Fixtures

LED tube light fixtures pre-wired and compatible with our T8 LED lamps.

LED Linear Fixtures

Linear lamp fixtures in 2-ft and 4-ft lengths. Plugs into standard wall outlets nd mounts using screws or magnets.

LED Shop Lights

Overhead light fixtures with hanging chains. Plugs into standard wall outlets.

UV-A LED Lights

We offer 365 nm and 395 nm LED lights for fluorescence and curing applications.

UV-C LED Lights

We offer 270 nm UV-C LED lights for germicidal applications.

LED Modules & Accessories

LED PCBs, panels and other form factors for a variety of industrial and scientific applications.

LED Strip Lights

Bright LED emitters mounted on a flexible circuitboard. Can be cut-to-length and installed in a variety of locations.

LED Strip Dimmers

Dimmers and controllers to adjust LED strip lighting system brightness and color.

LED Strip Power Supplies

Power supply units to convert line voltage to low voltage DC needed for LED strip light systems.

Aluminum Channels

Extruded aluminum channel profiles for mounting LED strip lights.

LED Strip Connectors

Solderless connectors, wires and adapters to join and connect LED strip light system components together.

In recent years, you may have found that the halogen bulb you've been buying for years is no longer available at your local hardware store. That's because LED spotlights are quickly being introduced to the market as a more energy efficient alternative.With the transition to LED technology, a lot of the metrics and points to consider are now different. If this is your first time purchase of LED spotlights, you might be worried, confused or frustrated.Not to worry! After reading our 4-point guide below, you'll be able to make a confident and educated LED spotlight purchase in no time.First and foremost, you will want to narrow down your LED spotlight search by determining what mechanical size and shape of bulb you will need.Generally speaking, there are three types of LED spotlights: MR, BR and PAR. The type name is typically followed by a two digit number, which indicates the bulb diameter in 1/8ths of an inch.MR16 bulbs are the smallest type of spotlight with a 2 inch diameter. These bulbs are typically used for lower brightness applications. LED spotlights of this size are typically 5-8 Watts.MR16 bulbs come in two variants that differ in base type (how the bulb is mounted into the socket).If you see a narrow, two-pin connector without rounded bottoms as shown in the photo below, you have a GU 5.3 version. These are almost always very low voltage (12V AC or DC).If you see a broader 2-prong connector with rounded bottoms as shown in the photo below, you have a GU 10 version. These are almost always mains voltage (120/240V AC).!Protip: you may sometimes find that certain manufacturers refer to MR16 bulbs with GU 5.3 bases as simply [MR16] (without the base designation) and MR16 GU10 bulbs as [GU10] bulbs. This is not technically correct but you may want to be aware of this when you are reviewing product specifications.The next size up is a PAR20 bulb, which is 2.5 inches in diameter. PAR20 bulbs are common in residential applications in smaller homes or where ceilings are not as tall. LED spotlights of this size are typically 13 Watts.The vast majority of PAR20 bulbs use the same E26 Edison screw base that standard A19 bulbs use, and operate on mains voltage (120/240V AC).PAR30 bulbs are similar in shape and function to PAR20 bulbs, but are quite a bit larger at 3.75 inches in diameter. These are commonly used in higher ceiling applications. LED spotlights of this size are typically 15 Watts.The largest of the commonly used residential spotlight sizes is the PAR38. At 4.13 inches in diameter, these are large and bright, rated at upwards of 100W for halogen bulbs. LED spotlights of this size are typically 18 Watts.Now that we've gone over the bulb types, how do you know which one to choose? The short answer is: follow the directions on the lampholder.If you take a look at any reputable lamp fixture, you should see a sticker or imprint noting the type of bulb size that is compatible.In this example, the lampholder says "USE PAR20 TYPE" so we know for certain that this is the type of LED spotlight that is needed.With halogen spotlights, color was never an option - pretty much all products from all manufacturers had the same color temperature and color quality.With LED spotlights, however, many color temperature and CRI options exist, making it more difficult to ensure that you pick the right one for your needs.Color temperature is a number that describes how "yellow" or "blue" a light's color is.Lighting for your home is ultimately a personal choice, but wto test. If you think it's too yellow, you can switch to K or K. If you think it's too blue, you can switch to K.Most of these color temperatures are readily available from most manufacturers.CRI is a bit tricky to understand because it is not immediately visible from just simply looking at an LED spotlight.CRI is score ranging from 0 to 100 which measures how accurate objects appear under a light. The higher the score, the more accurate.What does accurate really mean, anyway?Let's say you are trying to light up a painting. An perfectly accurate LED spotlight would make the painting look exactly the same as it does under a halogen bulb.An inaccurate (low CRI) LED spotlight, however, would make the painting look "off" - the colors might appear mismatched, washed out, or indistinguishable.This is not limited to paintings or artwork. The appearance of furniture or food can also appear to be lacking in color and dull, if the LED spotlight has insufficient CRI.Well, what is a sufficient CRI number?How do you know what an LED spotlight's CCT or CRI is? Virtually all manufacturers will be able to providethis to you on the product specification sheet or packaging.You are likely used to thinking of bulb brightness in terms of watts - a 60 watt bulb is brighter than a 40 watt bulb.But don't forget that watts are a measure of electrical energy in, not necessarily the total light output.This was an acceptable way to estimate brightness because most halogen bulbs have the same amount of efficiency.LED spotlights are far more efficient than halogen bulbs. What this means is that watts is no longer a useful measure of brightness....use much more energy (in watts) than...to generate the same amount of light output.Instead of focusing on watts in, you will need to focus on the light output, which is measured using themetric.Not sure how many lumens you need? You can estimate what you need based on what you had installed before switching to LEDs.This can be calculated using a simple formula:Lumens = [watts in halogen] x 15For example, if you had a 40W halogen bulb, you can can estimate the number of lumens by multiplying 40 by 15 = 600 lumens.You will find the number of lumens listed alongside the product specifications.Finally, you will want to consider the shape of light that comes out of the LED spotlight.The shape is described as beam angle. Beam angle is defined as the angle in which 50% or more of the light is distributed.If you have a narrow beam angle, you will be concentrating the light into a smaller area, thereby increasing the amount of light that shines in that area.If you have a wide beam angle, the light will be more dispersed. You will be able to illuminate a wider area, but you will be "diluting" the light across a larger area, effectively reducing the amount of illumination on that surface.Also keep in mind the cone shaped light distribution of LED spotlights. As you increase the distance from the lamp, the dispersion increases as well.This means that if you have high ceilings, you will want to make sure you select a narrow beam angle LED spotlight to ensure that the light can "reach" before dispersing.We hope you found our recommendations helpful. Ultimately, lighting is oftentimes a personal and aesthetic choice, and the best test is a visual test.If you have a relatively large project, it is probably a good idea to purchase one or two LED spotlights first to test and make sure that the color and brightness are what you expect.If it looks okay, then you can proceed with purchasing the rest!

If you want to learn more, please visit our website Surface Ceiling Light.

by Richard Wilson, B.Sc.
Over the last decade, exterior shading has become more popular in the U.S. construction market. However, many architects and building owners still have limited knowledge about these systems and why they should be considered part of the building design.

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This article explores 10 frequently asked questions about exterior shading, while providing insight into available systems and how they can be an important part of the buildings environmental control.

1. What exterior shading systems are available?
A wide range of exterior shading systems are available, but they can be broken down into three broad categories of systems:

• fixed louver;
• adjustable louver; and
• retractable.

Fixed louver systems include projecting sunshades generally installed at the head of the glazing (i.e. brise-soleil systems), as well as fixed vertical or horizontal louvers installed in front of the glazing. These systems are designed to remain in place at all times and need to be able to withstand all weather, including wind, ice, and snow. The shading performance varies depending on the systems projection and the louver profile selected, as well as the angle of the louvers and the spacing between them. These items need to be evaluated during the design process to ensure the system provides sufficient shading during periods when solar gain is an issue.

Brise-soleil systems only address high sun angles and, as a result, they generally will only be effective on south or near south-facing elevations. They also only provide shading during the summer. During the winter months, the low sun angles mean these systems provide little or no shading.

The effectiveness of fixed horizontal or vertical louvers depends on louver size, angle, and spacing. These systems normally only shade higher sun angles in order to allow views to the exterior, and are most effective on south-facing elevations. They can be installed on east and west elevations, but will normally not protect occupants from the low sun in the early morning or late afternoon.

Vertical and horizontal adjustable louver systems can be motorized, allowing louver angles to be adjusted to give more responsive shading, particularly if they are connected to an automated control system. The systems do not retractthey will always remain in front of the glazingbut can be moved between the fully open and closed positions.

The method of control can range from switch operation, where occupants operate the system according to their needs, to a fully automated system that responds to the sun conditions and adjusts the louver angle to prevent any direct sun penetration. The systems are generally controlled independently of the interior lighting systems; ideally, levels are automatically adjusted to supplement natural daylight where required. Since the systems only operate from time-to-time, and only for a few seconds to adjust the louver angle, energy usage is not significant, particularly compared with the savings that can be achieved through a reduction in HVAC requirements.

 

 

 

 

 

 

 

 

 

 

 

 

2. Why is an exterior system more effective than an interior one?
In broad terms, an exterior system is better than an interior one because it prevents a large part of the suns energy from reaching the glazing and entering the building. If the solar energy does not get into the building, it does not have to be dealt with.

Energy from the sun is short-wave and carries little heat. Heat is only produced when the solar energy is absorbed by a surface (e.g. carpeting, furniture, clothing, or skin) and is then radiated as long-wave infrared (IR) energy.

An interior shading system can:

• allow solar energy to pass through;
• absorb solar energy; and
• reflect solar energy back through the glazing.

The reflected solar energy is not an issueit remains short-wave and does not cause any heat gain. The transmitted energy is absorbed by surfaces in the building and is radiated as heat. The energy absorbed by the shading system is then radiated as heat and most of this heat is then trapped inside the building, particularly if low-emissivity (low-e) glazing is used.

An exterior system is similar to an interior one with regards to the transmittance, absorption, and reflection of solar energy. Anything absorbed by the shading system, however, is radiated as heat on the buildings exterior. Since glass is not transparent to long-wave energy, little of this radiated heat gets inside the building. Accordingly, an exterior system eliminates one of the two sources of heat gain, resulting in much greater reduction in solar gain inside the building.

Performance data is readily available for shading fabric. Consider a popular fabric in a grey-white color and a particular type of glazing (e.g. low-e, argon filled, double-glazed unit), the g value is 0.13 when the fabric is installed on the exterior, but increases to 0.43 when installed on the interior. The g value is the sum of the direct and secondary solar transmittance into the building. The secondary transmittance comprises the amount of solar radiation absorbed by the combination of glazing and shading system which is then convected or radiated into the building. In North America, the g value is also known as the solar heat gain coefficient (SHGC).

Even with a white fabric, which has the highest level of reflectance, the comparison is 0.16 for an exterior installation compared with 0.36 for an interior one.

The message is therefore straightforwardfor the most effective solar control, the shading system should, wherever possible, be installed on the exterior. There will be some situations where this is not practicalfor example, high-rise buildings with 25 floors or more. In these cases, the use of a shading system inside a ventilated double façade is a potential approach, although shading is just one of many influencing factors when pursuing this type of façade construction.

3. What are the main benefits of an exterior shading system?
The primary benefit of an exterior shading system is a reduction in HVAC requirements. As discussed earlier in this article, exterior shading blocks a large part of the solar gain before it comes through the glazing and into the building. If there is less solar gain, then the size of the HVAC system can be reduced. This results in a saving in the initial capital costwhich can wholly or partly offset the shading systems costas well as the ongoing running costs. The most effective shading systems, such as exterior venetian blinds, can block more than 90 percent of solar gain, having notable impact on reducing the HVAC requirements.

Some buildings, however, need to be cooled in the summer, while also have heating requirements in the winter. If a retractable exterior shading system is used, it can be turned off in the winter months, allowing the solar gain into the building and providing an element of free heating. During those months, glare and light control issues would be addressed with an interior shading system such as a roller shade.

Another benefit is natural daylighting. Exterior shade systems can help optimize the use of diffuse daylight to illuminate interiors, reducing the need for artificial lighting. More than 30 percent of the energy costs of an office building relate to artificial lighting, so if lighting needs can be reduced, significant savings can result.

A well-designed shading system also contributes to comfortable working conditions which can lead to increased productivity. A good shading system manages both heat and glare while providing access to outside views. Finally, using exterior shading systems can significantly contribute to a buildings appearance; it can become a design feature as well as one bolstering efficient building performance.

 

 

 

 

 

4. Can exterior shading systems be used on both new and existing buildings?
It is always easier to apply exterior shading systems to a new building, as integration issues can be reviewed and connection details developed during the design phase. Fixed exterior louver systems can exert significant loads on the façade, and if they are being attached to the curtain wall, mullions might need to be reinforced to support them. Even with lighter, retractable systems, such as venetian blinds, it is helpful to be able to discuss attachments with the curtain wall contractor during the design phase so brackets can be specified to avoid problems such as cold bridging.

However, it is possible to apply external shading to existing buildings. While the original building design would not have anticipated exterior shading, structural elements can be incorporated as required, to allow installation onto the existing façade. The structure, rather than the façade, would then accommodate applied loads (i.e. wind, ice, snow) as well as the weight of the system itself.

If an operable system is going to be used with an existing building, it will be necessary to look at the electrical requirements and determine how conduit and electrical cabling can penetrate through the façade to allow connections to be made to the blinds or shades.

5. What are the common methods of attachment to the building façade (and what issues need to be considered)?
With both new and existing buildings, installation of an exterior shading system might involve attaching directly to the curtain wall mullions, to brick or concrete masonry units (CMUs), or through cladding to steel structure. It is probable different brackets will be required for each situation, and these will often be developed to meet the specific project requirements.

Exterior roller shades and venetian blinds are generally installed just above or at the top of the glazing. They are relatively lightweight and, because they are retracted when the wind speed exceeds a defined level, they do not apply significant loads to the façade. This means lighter aluminum brackets can normally be used to connect the head box to the façade. Pre-tensioned side guide wires are also generally used to prevent movement of the shading system under wind load (the other option is extruded side guides) and each of these will be tensioned to approximately 22.7 kgf (50 lbf).

Since exterior louver and brise-soleil systems remain fixed in place in all weather conditions, they apply more significant loads to the façade. The brackets for the system will therefore be designed in accordance with the loads defined in local building codes, and bolts or other fasteners will also be selected based on the maximum loads. If the systems are being connected to the curtain wall, it is possible the mullions will need to be reinforced with steel. This is particularly the case with brise-soleil systems, which project some distance from the façade and, as a result, generate significant turning moments and shear forces at the connection points. With these types of systems, structural calculations will always be undertaken to determine the applied loads and the impact on the façade design and building connections.

Other issues that need to be considered include separation of dissimilar metals, cold bridging, and water penetration, as well as relative expansion and contraction between the shading system and the façade. Given these issues, it is strongly recommended the shading requirements are reviewed and discussed during the early stages of the design process.

6. Will the buildings location and the glazings orientation influence the choice of exterior shading system?
There are many factors influencing the choice of an exterior shading system. Two significant ones are building location and glazing orientation.

As seen in Figure 1, the movement of the sun during the year (shown by the blue lines) is significantly different between two extremes in the United StatesMiami, Florida, and Anchorage, Alaska.

In Miami, the sun angle is approximately 86 degrees, and almost vertical in the sky, at 12:00 p.m. on June 21. In Anchorage, the sun has a peak altitude angle of approximately 51 degrees, which is not much greater than the highest winter sun angle in Miami of 41 degrees. The sun also sets much further to the south in Anchorage during the winter compared to Miami.

Given the differences in sun movement, the optimal shading strategies will be different. In Miami, fixed projections will be effective; while in Anchorage, retractable and adjustable systems offer much more flexibility in controlling solar gain.

The glazings orientation will also have a significant impact on system choice. The graph in Figure 2 shows the incidental solar radiation on different orientations of glazing for a building in Indianapolis, Indiana. As expected, the solar radiation on the north elevation is the lowest as there is no direct sun. However, the background radiation is still reasonably significant, particularly in the summer.

The solar radiation on the east and west elevations is similar, with the maximum values occurring in the summer. Interestingly, the maximum solar radiation on the south elevation occurs during the colder months. In the middle of the summer, the high sun angles mean the incident radiation falls. The maximum exposure to solar radiation, however, occurs at the roof. Therefore, any skylights will potentially cause significant solar issues.

Given the variations by façade, fixed systems might work on the south elevation, but operable ones will be better east and west. Although vertical louvers might work on the east and west elevations, horizontal ones are generally better for controlling the solar gain and allowing views to the exterior.

7. How do exterior shading systems cope with adverse weather conditions?
As previously highlighted, fixed louver systems are designed to take account of the maximum applied loads. With brise-soleil systems, the loads at the attachment points might be significant, particularly if projections are substantial. If this is the case, diagonal brace rods might be incorporated into the design to allow the load to be shared between two attachment points. With fixed systems, ice buildup and the risk of falling ice must also be considered. Therefore, brise-soleil systems might be inappropriate for tall buildings in urban areas.

Retractable systems such as exterior roller shades and venetian blinds are more lightweight than fixed systems and are designed to retract when the wind speeds are high. Standard roller shades need to be retracted at relatively low wind speeds (up to a maximum of about 32 km/h [20 mph]) and will not be appropriate for windy locations or on tall buildings. There is, however, a generic version known as a zip system, which allows the fabric to be locked into side tracks. This type can operate in wind speeds of up to 144 km/h (90 mph) and is suitable for tall buildings.

Ice is also a potential issue, but should not be a problem if the systems are protected in the raised position. Automated controls will ensure the systems are only deployed when there is sun. Temperature and humidity sensors can also be used to stop the blinds or shades from being operated when there is a risk of icing. In locations with a cold winter climate, buildings generally require heating in the winter months. It may be appropriate to leave the exterior shading systems in the retracted position during these periods and allow the solar gain into the building as a free source of heating.

8. What maintenance is required?
Most exterior shading systems require little or no maintenance. Fixed louver systems need to be cleaned periodically to maintain the warranty on the paint finish, but no other maintenance work is required.

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Adjustable and retractable systems also require little or no maintenance. Nevertheless, it is recommended they be inspected on a periodic basis to check the systems are correctly operating, guide cables (where used) are adequately tensioned, and there is no evidence of damage or general wear and tear to components.

9. How can exterior shading contribute toward achieving LEED certification?
There are numerous areas where the use of exterior shading system can help achieve credits for Leadership in Energy and Environmental Design (LEED) certification. These include:

• minimum energy performance: use of exterior shading systems can assist in achieving a five percent reduction in building performance compared with the baseline building (in many cases, the reduction achieved is substantially more);
• optimize building performance: using exterior shading systems can help in achieving reductions beyond the minimum requirement;
• thermal comfort: exterior shading systems can potentially assist in achieving the requirements of American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 55-, Thermal Comfort for Human Occupancy; and
• daylight: to achieve this credit it is necessary to provide manual or automatic (with manual override) glare-control devices for all regularly occupied spaces (exterior shading systemspossibly in combination with interior onesallow this to be achieved).

10. Do exterior shading systems make sense in terms of costs and benefits?
To justify using exterior shading systems, it needs to be demonstrated it makes economic sense to do so. Determining the cost of an exterior shading system is a straightforward exercise, but measuring the benefits can be more difficult. It is therefore important the shading system be considered in the context of the building as a whole, rather than as an isolated system, as it can impact several areas of building performancenotably lighting and the HVAC system.

In the past, it has often been the case the shading systems performance was not taken into account when sizing the HVAC system. In this case, it is difficult to justify the use of exterior shading since the potential cost savings from reducing the size of the HVAC system will not be achieved. However, the mechanical consultants who deal with the heating and ventilation systems are now much more aware of the impact of effective shading, and are generally able to take this into account in their calculations.

Conclusion
The traditional approach to windows has been to use interior shading systems to control light and glare, and to address solar heat gain through the HVAC system. Increasing energy costs, requirements for improved façade performance, and greater environmental awareness are leading architects to look for alternative solutions.

Exterior shading systems will not be appropriate for all buildings; where they are used, however, they can make a significant contribution to the buildings performance as well as the building aesthetic. There is no question more architects are considering exterior shading, and, as understanding grows, exterior shading systems will become an important element in the design of high-performance buildings.

Richard Wilson, B.Sc., is a consultant to Draper Inc., and has been working with the company to introduce a range of exterior and specialty shading systems. He has been involved in the solar shading industry for more than 20 years. Wilson can be contacted by at .