Updated: Nov 6, 2018
I was in the middle of writing this blog when I looked at the window to gather my thoughts… then I realized that it has been my habit to look out the window when I think, as if there’s something out of the window that will inspire me to do a better job. You have this habit too? I wonder how many of us do this – looking out the window to gather our thoughts. The thing is I get distracted when something catches my eye – a squirrel on a tree, the rustling of the leaves on a windy day, and sometimes even fingerprints on the glass. I end up enjoying the scenery or else getting up to wipe off the dirt.
Some people think that if a window is holding up, it’s fine. As long as there are no cracks, it’s fine. If it’s not leaking… as long as it’s just a little dirt… The truth is, the longer we wait, the more it is difficult for us to maintain the window in the long run. The kind of care we give it shows how much we care for it. Maintenance, years of exposure to the elements, and the kind of window that you have (brand and materials) - all these have an impact on the life of your window. Cleaning it is just one component of window care.
The effects of improper maintenance are not a problem when something is brand new, be it windows, furniture, a dress, or some gadget. As the new thing ages, it sometimes becomes a fixture. It is human nature to lose interest and what was once regularly maintained becomes less and less cared for over time. It really is a discipline and a sign of our good stewardship when we take care of that with which we have been blessed. Inevitably the day will come perhaps before we hold an event where loved ones or others will be gathering, or when we decide that we must move onto another space and have need to sell the home that we suddenly take notice and realize that our windows are not like what they used to be.
Windows are best maintained when cleaned annually or semi-annually. This prevents build-up of layers upon layers of dirt and grime from building. When there are years of buildup it will take hours upon hours for your window cleaner to remove what’s been sitting there for ages. Worst case scenario, you will have to replace your windows if the buildup cannot be removed and you want a better view, because the reality is that there’s only so much pressure/agitation a window cleaner can apply. The topic on buildup will discussed in a separate blog.
In the process of cleaning your windows, your cleaner is likely to notice damage to the window and/or the screen, so in this case ask your window cleaner to take note and report back to you on those items. He should be Happy to set aside a damaged or screen, for example. so, you can have it replaced.
New Windows, Please!
The last thing we wanted to accomplish with this research is encourage you to purchase new windows. The reality is that replacement windows are extremely expensive and can be pretty inconvenient. It is not uncommon that a family can spend forty thousand dollars or more on replacement windows. Such a purchase ought to be thought of as an investment. As such, one should consider the future value and return on the asset from a financial perspective. Obviously, if your window is cracked, chipped, broken, warped or damaged, you might want to replace it with a new one. If the window is one that you often peer through the desire to replace your view will be amplified. In some cases where there’s no damage to the glass, perhaps you just need the trim replaced instead of changing the entire unit of the window, especially when they show wear and tear. You see, over time even with the best of care, windows will slowly show wear. For example, wood windows can become warped from exposure to moisture (also high relative humidity) or excessive light. This may make the window too tight to operate correctly in some places while creating gaps in other areas.
What are the other instances where you might consider replacing your window?
1. If you are having difficulty opening and closing your windows, likely you are dealing with drafts, exposure to the elements, security issues, not to mention intrusion of unwanted insects as well.
2. You are craving for some change so you want to update your window by replacing your old-style windows like storms or single pane glass to the more modern and efficient double or triple pane glass. You are also tired of dealing with hard-to-find or discontinued replacement parts.
3. Your single pane window is becoming a pain by not protecting your furniture, carpet, paintings, and window treatments from the sun’s UV rays and is thus fading those fabrics.
4. Your widows haven’t been cleaned in a long time so much so that dirt and grime has adhered to it that you cannot scrub it vigorously without the high risk of damaging the window ( it needs to be cleaned by a professional).
5. You want to save on your energy bill and with better insulation so your heater or air conditioning unit won’t have to work as hard.
Perspective on efficiency: If the new windows promise to be 20% more efficient, that savings does accumulate over time. It is wise however, to do the math to determine when you might reach the break-even point on your investment. Ask yourself: How does such an investment fit into your overall life goals? Carbon footprint versus taking a trip to the Holy Land for example. And if you aren’t buying new windows what would be the next best thing you might do with your resources? This way your ultimate decision will be one that you won’t live to regret.
6. Acoustic insulation is desired because your old window couldn’t keep the noise from outside at bay even when it is shut.
7. Many of the newer designs in windows are aesthetically pleasing. If the purchase of new windows is to enhance your enjoyment and the enjoyment of those you love, this might enough reason to shop. So be it. You will be armed with good information.
Properties of Glass
By no means am I trying to pose as a science teacher, but by refreshing your memory about the general characteristics of glass you will have a better appreciation of its qualities and a sound understanding of how to care for your glass properly. Also, this section was carefully researched for those knowledge warriors who might wish to be armed with impartial and pertinent information on the properties of glass before meeting with a salesman.
1. Chemical Resistance – Glass is known to resist most chemicals/acids – except hydrofluoric, and phosphoric acid (at high temperatures). Unprotected surfaces of the glass will corrode if exposed to alkalies. Mineral deposits are easy to remove during initial stages but hard water with magnesium, calcium and other mineral compounds that has built into the surface will turn into a white crust that can eventually damage the glass.
Practical Implication: Strong cleaning agents and strippers left to dwell on glass will damage it over time. Stripping paint, power washing (insufficient rinsing) and poorly adjusted sprinkler heads are common causes of these problems.
2. Conductivity - Glass is a poor conductor of electricity but is a better conductor of heat.
3. Elasticity – Glass can be brittle. Unlike metal which can be bent in many ways, the same does not hold true when it comes to glass which breaks when you bend it.
Practical Implication: If you have a chip in a window pressing on it even slightly can cause a spider web of cracks. You can determine if a window has a chip or scratch by feeling the surface with the tip of your fingernail.
4. Light Transmission – Glass have optical properties. It reflects light, bends light, transmits light very efficiently, and absorbs light with great accuracy. Also, it is surprising to know that a seemingly clear glass is not totally transparent. Transmission capabilities vary depending on the glass type and the thickness. A 6 mm-thick piece of clear float glass will only capture around 13-percent of light within the visible spectrum, allowing 87-percent of the visible light to pass through it. A ray of light is slightly offset when it passes through a window pane, and the thinner the glass the smaller the offset.
Practical Implication: Thick multi pane windows will provide a marginally duller view than thin single pane windows. This is another trade-off for increased energy efficiency. This property is precisely what makes window cleaning a dynamic and challenging task. As the light changes throughout the day the window cleaner must by force of habit inspect his windows from every geometric angle.
5. Resonating Frequencies – A glass has a natural resonance at which it vibrates and creates a sound. A huge force that makes the glass vibrate, as in the case of a storm, can cause a glass to break.
Practical Implication: In the nursery, it is best to place the crib away from the direct fallout of shattered glass. Also, it is best to have in place a type of window treatment that will help to absorb the possible impact in such an extreme circumstance.
6. Strength – While seemingly totally fragile, glass is also known to have a great capacity to resist compression.
7. Thermal Resistance – Glass is formed at high temperatures. It is known as a highly viscous liquid but isn’t liquid at all. They are created by melting solid substances at high temperatures and then cooled rapidly (known as quenching), and generally melt again when exposed to very high temperatures. A regular 6mm-thick float glass typically ruptures if heated to 75-degrees Celsius and then plunged into 20-degree Celsius water (a temperature differential of 55 degrees). Architectural glass is enhanced with the addition of substrates, laminates and other technologies to maintain rigidity at high temperature, for fire protection. Glasses are now built for thermal endurance and are toughened with a temperature differential of around 250 degrees for this purpose. Glass retains heat rather than conducts it. They absorb heat better than metal does.
8. Weight – Some glasses can be deceptively heavy even when they are small and look light. Take into consideration the weight of your architectural glass when replacing or remodeling your windows.
Most companies have innovated ways and means to make sure that the architectural glass they manufacture will meet the needs of their clients. We will discuss these proprietary innovations later when we move on the different brands of glass.
If incorrectly designed, concave surfaces with extensive amounts of glass can act as solar concentrates depending on the angle of the sun, potentially injuring people and damaging property, just like what happened to a car in London.
Practical Implication: Mistakes happen in the manufacturing process. Even with modern quality controls like Six Sigma, somehow mistakes make their way into installations. Laminates can be printed on the wrong side etc. It is best to look over your windows if possible before you accept them for any obvious inconsistencies from one unit to another.
The 2006 International Building Code (IBC, 2006) is the most current building code enforced in most jurisdictions in the United States. ASCE/SEI 7-05 is an integral part of building codes in the United States. The earthquake load provisions in ASCE 7-05 provides specific requirements for nonstructural components including requirements for architectural glass.
Options When Window Shopping
In all likelihood you will want to replace your window in the same style as your old one, and if you know the glass dealer, then you can simply purchase it and have it installed.
Let’s say your window is beyond repair, or you just want variety this time. You want to change windows but not exactly like the one you are replacing, in terms of style, brand, etc. This means that you have to remove and replace the entire window assembly. Replacement windows typically guarantees a better fit than window inserts.
Get inspiration from Pinterest, Houzz or other sources (a magazine, a house you have seen before, etc.) if you want an overhaul or you are working on a construction project. Research, research, research – online and/or offline. In my earlier studies of human behavior, I have learned that before going window shopping (literally and figuratively), the shopper already knows what he wants before he goes to the store. When window shopping, you naturally must consider your priorities, and these may range from two or more of these factors:
1. Architectural design of the house or the window’s position in relation to the sun – Here you consider solar heat, light transmission, and moisture. There are glasses that will protect you and your furniture from UV rays.
2. Brand – A trusted brand, especially one you are familiar with is an important factor. They may not be as cheap as you expect, but then again for something as functional as windows, you must weigh your options carefully. Some brands have been founded and are made in the USA, they have been around for so many years, and have supported many local families. These represented in this blog are popular in the mid-western market. Since the Midwest is at least in my opinion the cradle of modern architecture, I am confident that these brands will hold their own against all.
3. Budget – When working on your budget, you factor in the following: styles, materials, features, the size of the project, and how you are going to install it (do it yourself or hire a pro?). How much are you willing to spend on the project? Don’t just scrimp for the sake of scrimping. Consider the long-term value of the products that you are going to purchase. Think of it as an investment. What’s the use in buying something cheap if only to replace it in five years or so because it is sub-standard? Also, expect wood to cost more than vinyl or aluminum. In some cases, glass kits are an option for those who are budget conscious. The newer fiberglass series from Pella are of special note, unmatched for durability, these are pricey but given the material they should hold up as well as your Boston Whaler does at sea.
4. Energy Efficiency –Most homeowners will want a window that is energy efficient. How do you factor in window cost versus energy savings? The truth is it is difficult to determine the payback associated with an energy-efficient window purchase but there are several items that go into this evaluation:
a. An expensive window is not a guarantee that it is a better insulator. With thousands of window options make sure you are comparing apples to apples when price shopping. Your research on U factors and IG units will come be useful so keep that information readily available when meeting with salespeople.
b. Newer insulating windows will no doubt reduce the load placed on your heating and cooling systems and could be another cost saver.
c. Check with utility companies. Some utility companies offer rebates for new window purchases so check with your local provider.
d. Upgrading windows will save money in the long run. While it may be difficult to put a specific savings on it. Research from one window company says older, single-pane windows are often the source of up to 30 percent of your home’s heat loss. So those new windows will reduce your utility bills.
Choose Energy Star Windows. The Department of Energy says that by installing Energy Star windows you will lower your energy bills and save money as compared to single-pane or double-paned, clear-glass. The DOE estimates these savings:
$126–$465 a year when replacing single-pane windows.
$27–$111 a year over double-pane, clear glass replacement windows.
The site also states that you can reduce your energy bills at an average of 12 percent through a purchase of Energy Star windows.
The best way to compare window brands that are energy efficient is to look for the National Fenestrating Council (NFRC) information (usually found in the label).
5. Frame – Consider the type of window frame that you have or want: Aluminum window frames conduct heat rapidly (which makes it a poor insulator). Fiberglass window frames offer high thermal performance as they have air cavities that may be filled with insulation. Vinyl window frames have hollow cavities that can be filled with insulation (in short it is a good insulator). Wood window frames also insulate well but absorbs moisture and expands and contracts in extreme temperatures.
6. Geographic Location – Depending on the climate of your location - wet, humid, hot, severe storms/hurricane, salty air – your home may have different window needs when it comes to material and glass choices.
7. Maintenance Requirements – Aluminum may scratch. Wood needs to be maintained, painted, and caulked. Vinyl is aesthetic even if not painted. You will also have to consider the maintenance requirements prescribed by the glass manufacturer.
8. Privacy – big and clear windows are nice but at the same time you don’t want your neighbors and people passing by to see what’s going on inside your house like they are watching free reality television; or worse, for them to see what you have in your home which could be an invitation to a break-in. Tinted, textured, or decorative glass affords privacy.
9. Style or Aesthetics – which may be one or a combination of the following: single hung, double hung, arched, awning, bay, bow, casement, egress, garden windows, hopper, jalousie, picture windows, round or half-circle windows, skylight, sliding windows, storm, and transom windows.
10. Sound/Acoustic Control – there are glass windows in the market that provide noise reduction
11. Security/safety – Maybe you live by the park where balls constantly fly could potentially break your windows, or perhaps you are just security conscious. If such is the case, consider the strength of the glass, it’s resistance to breakage, and its ability to prevent forced entry.
12. Termites – Termites will ruin the frame of your window, will ultimately ruin your entire window, and will ruin your day as well.
13. Warranties/Reliability – You will want to get the most for your money, so it is important that you consider the warranties that go with the product you intend to purchase. Most companies will claim a lifetime warranty but take note that “lifetime” here does not refer to the customer’s lifetime or the lifetime of the home. In most cases in refers to the lifetime of the window, which is typically seven years. It’s the same rule in Michigan, warranties are generally for seven years, unless the manufacturer or retail specifies otherwise. Name brand window manufacturers normally guarantee for a longer period. When window shopping, it is best to clarify what the warranties are and for how long, this way you will know what to expect and at the same time be able to weigh if it's a good investment. Make sure that you have your salesman go over the of their product warranties. The devil is, as they say, is in the details.
In some cases, there is no need to replace the entire window especially if some frames are still in good working condition. In this case, you can opt for an insert window installation which involves replacing the window sash assembly but keeping the window frame, sill and trim intact. This installation process is faster, simpler and often cheaper than a full frame replacement. The problem with inserts is that if you don’t have the proper you’re your new window may not be as aesthetic, energy efficient, or operational as you might expect compared to the more expensive full window replacement.
New windows can be custom-dated for a precise fit. On the other hand, ready-made windows are also available at the stores for your convenience. Bear in mind that when you purchase a ready-made window the measurements may not exactly fit the opening of the window you seek to replace. Fear not, retrofitting processes can be applied. Either way, you will require a professional to mount it and to make sure that your window is securely installed. When you have a professional do it, he will in all likelihood be able to assess existing problems that you are not even aware of.
Step One: Identify Your Type of Window
Assuming that you are working on a full window replacement project. The first step in the process is to know the type of window that you have:
Awning - a window that is hung horizontally, hinged on top, so that it swings outward
Bay and Bow - a window or set of windows jutting out from the wall of a building and forming an alcove within
Casement - a window that has frames hinged on the side and that opens outward
Double-hung - a window having two sashes that slide up and down
Gliding - window with two sash where one sash slides horizontally past the other
Hinged Inswings - casement windows, in which a hinge attaches the window sash to the window frame
Sidelights - windows that flank either side of your entry door
Stationary – windows that don’t open
Specialty – stationary windows characterized by their shapes, curves, and dramatic angles (peak pentagon, trapezoid, quarter circle, half circle, springline, oval, circle, octagon, arch)
Transoms - windows that go over the door
A homeowner can combine the different sizes and shapes of the types of windows enumerated above – twin transom over twin double hung, twin casement, twin stacked awning, half circle over gliding, quarter circle over double hung, arch over double hungs and picture window, segments over double hung windows, etc. - and form what is known as a combination window. Different configurations can also be made, depending on the number of panels to be had.
Step Two: Know Your Type of Glass:
Now that you know what your priorities are and what benefits you expect to get from your windows, it’s time to consider the glass type and their pros and cons.
Annealed or Float/Clear Glass – known as the standard and basic architectural window glass type which is made by slowly cooling the glass to relieve any internal stresses; Application: Ideal for homes and businesses; Basic material which is used to produce more advanced products through further processing such as heat strengthening, tempering and insulating, laminating, toughening, coating etc.
• Budget-friendly especially for quick replacements especially basement windows
• Colorless, so it won’t distort the view outside a window
• Not strengthened or tempered so it is not really the ideal choice for windows, as it’ll leave shards and large, sharp pieces if it is broken.
• It also won’t help you save on any energy efficiency or protect your furnishings from ultraviolet rays
• Not as aesthetic as other types of glass
• Some states have building codes that require tempered glass
Bullet Proof Glass - laminates consist of multiple plates of glass with a internal polycarbonate plates bonded together by interlayers of polyvinyl butyral or aliphatic urethane; can hold 46,000 lbs of pressure and pressure levels as high as 20 PSI;
Application: Mostly used in buildings (military institutions, government buildings, banks, public buildings, airports, post offices, telephone exchanges, petrol stations)
but is being marketed to homeowners as well
• Stronger than regular glass
• Laminates can resist bullet penetration from a variety of small arms and rifles, and other objects
• Provides safety measure
• With repeated impact, the glass will eventually break
• More expensive than regular glass
• More difficult to cut and size
Chemically strengthened glass - a type of glass that has increased strength by submerging the glass in a bath containing a potassium salt (typically potassium nitrate) at 450 °C (842 °F). This causes sodium ions in the glass surface to be replaced by potassium ions from the bath solution
Application: Harsh and challenging environments
• Typically six to eight times the strength of annealed glass
• The process can be used on very thin pieces of glass
• May be cut after strengthening, but loses its added strength within the region of approximately 20 mm of the cut
• When the surface of chemically strengthened glass is deeply scratched, this area loses its additional strength
Glass block - also known as glass brick used in areas where privacy or visual obscurity is desired while admitting light
Developed in the early 1900s to provide natural light in factories, became popular in the 1930s and '40s then became out of fashion in the 1960s and '70s
Application: commonly used as a bathroom window in homes, resorts, or public pools
• 10 times more energy efficient than basement or bathroom windows
• Secure and increase privacy
• Cost effective, maintenance free, add more light
• Very difficult to break
• Green Building Credits - helps a home qualify as a LEED-certified or Energy Star-certified building; Green buildings have a resale value that's between 5 percent and 35 percent higher than comparable structures
• No Natural Ventilation - require homeowners to continue using their heating or air conditioning system to circulate indoor air
• Sick Building Syndrome - can be a problem when flooring is cleaned with harsh chemicals or when cabinets are refinished using foul-smelling, toxic paint strippers
• Substantially heavier than conventional timber frame and drywall construction and will require increased engineered support
Heat Strengthened Glass – these are annealed glass panels made twice as tough by reheating it above 1200 and then cooled to induce surface compression; intermediate in strength between annealed and toughened glasses
Application: roof windows, facades, conservatories, glazing commercial buildings, performance and sports halls, swimming pools, hotels and restaurants, hospitals, museums, banks
• Tougher than lower grades of glass, but it can still shatter and break into sharp pieces
• Can take a strong direct hit without shattering
• Often used where security is a concern and because it holds its shape it remains in the opening and can withstand more force for a longer period of time, making it much more difficult to get through
• Not cooled quite as quickly as tempered glass, so it’s not as strong
• Has a weak edge that by simply tapping the edge of heat-strengthened glass with a solid object, it is possible to shatter the entire sheet
• Has a larger break pattern than tempered glass
• Not often used for exterior windows until it has also been laminated
Heatable glass - a relatively new product, which helps to find solutions while designing buildings and vehicles, based on usage of energy-efficient low-emissive glass that is generally simple silicate glass with special metallic oxides coating
Used in architectural applications for the past 30 years to prevent condensation and provide radiant heat; evolved since the late 1950s to be used for melting snow on glass roofs and was then effectively inverted and used as the heat source inside the building
Application: all kinds of standard glazing systems, made of wood, plastic, aluminum or steel; windows of cottages, office buildings and also big areas—leaded panes, translucent roofing, garret windows, canopies, etc.
• Can be used as the principal system of heating and can be combined with floor and ceiling heating thereby making it cost-efficient as well
• Used for defogging and prevention of frosting of windows of pools, saunas
Has a current-carrying coating, it can be used as the sensor of alarm systems
• Some heatable glass have a high rate of opalescence, especially after multicoat lamination, with the lapse of time yellowness appears
• Some have low shear strength, especially in low temperatures; it results in delamination (layering)
• Environmentalists dispute the idea that this is an efficient heating system because: (1) even high e-value windows are poor insulators compared to insulated walls, (2) heating window ejects much of the radiant heat outside, and (3) this type of heating may encourage the use of larger windows in a house, making them less energy efficient.
Insulated Glass - may be in the form of two or three panes of glass, with argon in the spaces between the panes. The glass panes in an insulated unit are typically laminated or tempered security glass. It is also known as double glazing which consists of a window or glazing element of two or more layers of glazing separated by a spacer along the edge and sealed to create a dead air space between the layers;
Evolved from older technologies known as double-hung windows and storm windows
Modern IG windows have spring-operated balancing mechanisms that also typically permit the top of the windows to swing inward, permitting cleaning of the exterior of the IG window from inside the building
Application: Commercial, residential, glass displays
• Optimized for energy efficiency
• Glass crafted with added insulation and gas inserted between the panes — typically argon or krypton — will have superior efficiency qualities
• Most insulated glasses come with a feature that ensures condensation won’t form in between the panes where you can’t wipe it off
• Helps in sound insulation/noise reduction
• Also provides security
• It is an expensive investment that pays off eventually
• Any leakage if the silicone sealant is not applied well might result in the condensation and damage of the glass unit
• Once damaged the glass pieces inside the unit cannot be removed and repaired and consequently the whole window will have to be replaced.
Glass Type: Laminated Glass - a coating is a special layer of polyvinyl butyral inserted between the panes of glass during manufacturing; invented in 1903 by the French chemist Édouard Bénédictus
Application: commercial (mostly shopping centers) and residential window, doors and side panels; Also used as household furniture, kitchen cabinet glazed doors and shelving, bathroom shelving, bar shelving, partitions and mirrors.
• Sound insulation
• A specially-treated safety glass that is resistant to breakage
• Simply harder to break and therefore more secure.
• May be required by your local building codes
• The interlayer can also give the glass a higher sound insulation rating
• When broken, the interlayer keeps the layers of glass bonded and prevents it from breaking apart
• It also eliminates 99 percent of ultraviolet rays
• More expensive than regular windows. This is because they require a lot more steps during the manufacturing process and because they have several layers of material.
• Not a whole lot of manufacturers exist. This not only drives the cost of laminated windows up, but also limits your choices. In addition, you might have to wait a few weeks before your windows are made, which can leave you vulnerable at the time.
Low-E Glass (Low emissivity glass) - specially coated to reflect thermal radiation. The low-e coating keeps out infrared rays, while light still filters through.
Application: Greenhouses and homes
Low-E Storm Windows: (1) add an exterior storm window with Low-E glass or (2) swap the existing glass with a Low-E substitute
Low-E in Sash: replace the glass in the windows with hard-coat Low-E glass but at the same time save historic windows.
Low-E Tint: Probably the cheapest and easiest option, find a tint that blocks the heat and doesn’t block too much of the visible light and apply it on the inside of the glass otherwise the tint will have a very short lifespan.
• Added protection from ultraviolet light
• During the summer, heat is directed away from your house, and in the winter, your indoor heat is reflected back in the house and won’t escape through the windows. This translates to lower heating and cooling costs.
• Protects furnishing from the fading effects of UV light
• Can be a pricey investment, but the savings in the long run can make it worth it
• Some types of low-E coatings cause tinting so check samples first before installing
Mirrored/Reflective Glass - To create mirrored glass, a panel is given a metal coating on one side. This coating is sealed with an extra protective sealant, creating a mirror effect
Application: usually in bathrooms (residential) or businesses
• Can enjoy natural light during the day yet affords privacy at the same time
• By reflecting back a high proportion of the sun’s light, the safety film also helps to keep the room cooler.
• Blocks incoming ultraviolet light that is responsible for a lot of damage to furnishings and fabrics.
• Treated windows don’t shatter so readily in the event of an accident. The film helps to hold the window together and can absorb a significant amount of shock.
Can help to reduce the amount of condensation by reducing the contrast between daytime and nighttime temperatures
• Pretty, but it’s not usually used for exterior windows
• Daytime privacy is more or less guaranteed but the film is not so effective at night when there are lights on in the room.
• May require more heating in the winter to maintain room temperatures even though the film will tend to retain the heat once it is generated
Can be very aggravating for neighbors who may become the unwilling recipients of the reflected light
Obscured Glass – a type of glass which allows light to come in, but can’t be clearly seen through; may be frosted, etched, coated or otherwise designed
Application: painted or laminated used for decoration, typically used as bathroom window, shower enclosures, wardrobe doors, cabinet doors
• The most popular type of glass for bathroom windows
• Transforms an old setting to project a new ambiance
• Better alternative to curtains or blinds
• Comes in various colors and patterns
• Enhances privacy and security where necessary
• Lessens sun glare, but not the illumination. If lighting is not a desired consequence, may choose the opaque frost
• Filters ultraviolet rays to prevent damage to the skin
• Conserves energy within the space as the film blocks the heat of the sun from entering
• Protects furniture and items such as rugs from the effects of fading
• Prevents splintering of glass in case of a storm shatter or breakage
• Projects a new stylish appearance
• Obstructs natural light
Self-cleaning glass - a recent innovation by (2001 Pilkington Glass and Neat Glass by Cardinal Glass); a nanometre-scale coating of titanium dioxide on the outer surface of glass introduces two mechanisms which lead to the self-cleaning property. The first is a photo-catalytic effect, in which ultra-violet rays catalyze the breakdown of organic compounds on the window surface; the second is a hydrophilic effect in which water is attracted to the surface of the glass, forming a thin sheet which washes away the broken-down organic compounds.
Applications: residential and commercial, especially homes with skylights
• It is supposed to save time and money on window cleaning and help to avoid the risk of accidents
• Available in various different thicknesses (typically 4–10 mm), with blue tints (to reduce solar glare in places such as conservatories), and with heat-reflecting inner coatings for improved energy efficiency
• About 15–20 percent more costly than conventional glazing
• Self-cleaning process happens slowly and continually, you don’t get the same wow effect after a real window cleaner does your windows
• It is never as clean and sparkling as a freshly cleaned pane but not as dirty as an uncleaned one either
• The cleaning process relies on sunlight and rain. Although the coating needs only a small amount of ultraviolet light for the photocatalytic effect to begin (so it works even on cloudy days), the titanium dioxide still takes 12–48 hours to absorb enough energy to work properly.
• The coating also takes a period of time to activate when it's first installed - anything from a week in summer to two months in winter, depending on the climate where you live
• You need water as well as sun, so if it doesn't rain for a period of time you'll still need to hose your windows down to remove the dirt. (Pilkington, a leading manufacturer of self-cleaning windows, says "In dry spells... your windows can be washed with a soft cloth and warm soapy water or hosed down gently," which sounds suspiciously like cleaning the windows yourself!)
• Photocatalysis only tackles organic (carbon-based) dirt, so it's not effective against things like salt deposits (if you live near the coast) and it won't remove paint splashes
• The coating is designed to last as long as the windows, it can still be damaged if you clean your windows with abrasive materials or harsh chemicals
• You'll still need to clean the insides of the windows yourself.
Tempered Glass - basically annealed glass but with quadrupled strength. The glass is heated to above 1200 degrees and then quickly cooled. To make heat-soaked tempered glass, the panes are baked at 550 degrees.