DIY Green Home Improvement » Windows & Doors

LED Lighting, It it Ready Yet?

rcovington — Mon, 07 Sep 2009 00:34:54 +0000

Yes, oil has dropped 50% in the last year natural gas has been more than cut in half in the last year, so your electric bill will go down…right? I would not count on it and given the political situation in the world today, you must consider the impact your new home or home improvement will have on energy consumption. There is also the

LED GU-10 Lightbulb

possibility you may face large increases in your electric bill if Cap & Trade passes into law. LED lighting is fast becoming a viable option for you to consider in the design phase for your house. LED’s have a solid history of performance in commercial applications. Most traffic signals incorporate LED’s. The typical traffic light will contain 196 LED’s and will draw 10 watts. To produce the same light requirement with incandescent lights would consume 150 watts. Replacing all 260,000 U.S. traffic signals now using incandescent would reduce electrical consumption by 2.5 billion kWh annually. This is just the tip of the iceberg of savings in this one example. Maintaining the incandescent light bulbs in all these traffic signals is far more expensive than the electrical consumption. With and average life of 2,000 hours, a typical signal will have to have the bulbs changed at least 4 times a year. Some LED’s will last 15-20 years. The cost savings from the reduced replacement cycle should justify the cost of replacing the existing bulbs, even with a unit cost for LED’s which runs 50-60 times that of an incandescent bulb. But the savings do not end here. If LED’s started to replace lighting in the broader scope of lighting both residential we would see savings from the reduced need to build new power plants, reduced emission from reduced power requirements for the plants to produce, reduced recycling cost to process the burned out fluorescent and incandescent bulbs and a host of other energy and economic impacts attendant to lighting. They could also solve the dilemma of Mercury in CFL that we al face with the demise of incandescent bulbs slated to occur in 2012. The cost of LED’s is coming down as their use spreads. To date the light output and the color rendition have been the main inhibitors to seeing them spread to general lighting purposes. Both of these issues are finding solutions through research and development. There are lighting solutions for the home now available for residential applications. Quasar makes a fairly broad line of LED light solutions that will work for your home lighting needs. Even if you investigate them and decide they are not right for you, it appears that the industry is looking to make the transition easy once the light source gains greater acceptance. In the mean time, you should look at the possibility of using these in your new home. The benefits are very attractive for the investment. Just imagine if you did not have to change a light bulb for 20 years.

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SHGC, Visible Light Transmission and U-Value

rcovington — Sat, 06 Jun 2009 03:47:00 +0000

The key factors to understand when judging the expected performance of a window or door are:

Solar Heat Gain Coefficient (SHGC)
Visible Light Transmission (Vt)
U-Value (U-Value)

These are the standards by which most test protocols evaluate glazing from.

Solar Heat Gain Coefficient (SHGC) -- is the measure of relative heat gain (compared to a piece of 1/8″ thick clear glass) that a particular piece of glass will absorb under exposure to the sun. Reducing the Solar Heat Gain Coefficient (SHGC) is a function of either tinting the glass and making it darker or coating the glass with low-emissivity coatings to reflect the amount of infrared spectrum most responsible for heating that the glass absorbs.

Visible Light Transmission (Vt) -- is a measure of the amount of total visible light that will pass through the glass, again relative to a piece of 1/8″ thick clear glass. Adding low-emissivity coatings coatings to glass will affect the Visible Light Transmission (Vt) factor pretty dramatically depending on the specific glass manufacturer’s method of coating.

U-Value (U-Value) -- is a calculated measure designed to represent the ability of the assembly (both pieces of glass, the air space, the frame components, etc.) to resist the transmission of cold and heat through them. This is a composite value of all the components and is not a relative measure. The lower the U-Value, the better able the assembly is capable to resist the passage of heat and cold. U-Value is the inverse of R-Value in measuring the same physical characteristics and thus the higher the R-Value, the better able to resist the passage of heat and cold.

Traps With Solar Heat Gain Coefficient -- (SHGC) and Visible Light Transmission (Vt)

Looking at the Energy Star website will tell you the recommended SHGC and U-Value you should have for your specific Climate Zone. But these recommendations do not take into account daylighting and the effect that Visible Light Transmission (Vt) can have on the performance of the overall structure during the heat/cool/light cycles. If you lower Visible Light Transmission too much, the daylighting in the interior will be reduced to a level that may require supplemental electrical lighting for some functions, or to make the environment enjoyable to the occupants. In evaluating the overall structure from a green building perspective, you must look at all the factors here.

Adding electrically generated light, uses energy for the lighting, but it also generates additional cooling loads on the HVAC system adding to the overall electrical usage. There have been studies done particularly on skylights, daylighting and electrical usage in commercial buildings which attribute a very significant increase in electrical usage to this phenomenon. So make sure you do not overshoot in reducing the daylighting in the home in pursuit of the gremlin of the lowest Solar Heat Gain Coefficient (SHGC).

U-Value is the relative constant in all this. Lowering Solar Heat Gain Coefficient (SHGC) will not in and of itself have a large impact on U-Value. Nor will lowering the Visible Light Transmission (Vt). The U-Value is a function of the physical properties of the glass, wood and/or metal that compose the composite of the unit and these are not affected by changes in the other values.

U-Value and Solar Heat Gain Coefficient in Climate Zone 4

If you live in Climate Zone 4, then U-Value becomes a more important consideration in judging the window performance overall. But in this zone, higher Solar Heat Gain can add incrementally to the heat inside the home and reduce the heating demand placed on the heating system. Thus, a SHGC of .65 will be of more benefit to you . You will also finsh that the High Solar Heat Gain low-e coatings will typically have higher Visible Light transmission in the .7 range.

So, you must understand the impact of all these factors as it relates to your specific location. When you are through evaluating on this basis, you will need to look at the air infiltration ratings. I will discuss this in another article.

This added 7/7/2008

Light to Solar Gain Ratio (LSG)

I ran across a new measure that helps you guage the relationship between SHGC and Visible Light Transmission. The new ratio is known as the Light to Solar Gain (LSG) and is a ratio of the Vt to SHGC. For instance if the Vt is .66 and the SHGC is .40 then the ration of .66/.40 or 1.65. The recommended ratio is 1.25 or higher. The higher the ratio, the higher the daylighting benefit. It also means that the glass transmits more light than heat to the interior, again a positive in the Southern climate zones 1,2&3.

Solar Heat Gain in Energy Star Zone 4

If you live in Zone 4, then it is desirable to have a higher Solar Heat Gain ratio in your windows. Otherwise your heating system will work harder in the winter and diminish your energy efficiency. The standard, 1st generation pyroltyic Low-e coatings (also known as High Solar Heat Gain Low-e, is the easiest method of obtaining a higher SHGC and still retain the reflectivity of the low-e as it pertains to winter infa-red heat retention in the interior of the home.

You may run into a problem in this regard as some window companies have settled on the more efficient (for zones 1,2,3) sputter coat low-e‘s as their “standard” offerings. They prefer to narrow the choices because it is less costly to offer fewer choices. Do not be disuaded. Stick to your guns and insist on the specs that meet the Energy Star qualifications for your home. Any window manufacturer can get the pyrolytic coatings. If they tell you they cannot, move on to a manufacturer that will give you what you need. Buying windows is like anything else, you will either get what you “buy” or you will get what you were “sold”. In the end, you must be responsible for the choice you make.

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Vinyl Windows, Top Value And Performance That Support Green Building Objectives

rcovington — Sun, 31 May 2009 15:46:55 +0000

Vinyl Windows offer the lowest cost to performance ratio of the the three major types of windows. Vinyl has a low co-efficient of thermal transmission relative to Aluminum and while they are closer, a properly designed vinyl window (with multi-chambered extrusion) will reduce the amount of cold transmitted through to the interior of the home.

Multi Chamber Profiles

Multi Chambered Vinyl Window

Multi chamber profiles create an insulation barrier of air that reduces the transmission of cold to heat. The optimal window profiles use two and preferably three chambers between interior and exterior faces. The multi-chambered profiles also increase the strength of the profile tremendously over a solid extrusion by increasing the surface of welded seam.

A typical welded profile will yield between 9 & 20 inches of welded seam. Some multi-chambered designs offer as much as 25 inches of frame and 14 inches of sash weld seam. This results in a weld that is stronger than the extrusion itself. Some manufacturers used to offer windows with mechanically fastened corners instead of welded. These would invariably separate early and begin a freeze-thaw attack or heat induced expansion that would shorten the life of the window and reduce its thermal performance. Avoid any mechanically fastened or glued corners. Always opt for a multi-chambered , welded corner window.

Colors In Vinyl Windows

Initially, vinyl windows were offered only in offered in white. This was to keep the cost down, but it was also to prevent obviating the issue of fading and color degradation. Over time, white PVC will become yellowish with age. Some extrusion manufacturers counter this by adding some blueish color to the polymers to balance this out. If you are driving around, and see some vinyl windows with a sickly looking yellow cast these were probably lower cost extrusions and you will see the result.
Additionally, the UV is the light spectrum most affecting the color degradation so the higher your altitude, the faster the process of color degradation will occur as UV at altitude is unfiltered. Some manufacturers now offer a rage of colors including darker browns. Be very wary of darker colors, especially at higher altitudes (Rocky Mountain Regions) as you will likely see a rather quick degradation of the color. There just is not a long enough history with darker colors under longer term exposure to intense UV. PVC formulations are improving, but more time is need to judge the effectiveness of the color imparting materials before taking the plunge.
That said, I have seen some beige colors under service for several years in the Colorado region that seem to be holding up quite well. One final caveat, PVC is subject to becoming brittle under long term exposure to high heat as in a desert environment. In these areas it is critical that you get a high quality, multi-chambered extrusion to counter the effects of long periods of exposure to high heat.

Maintenance of Vinyl Windows

The most attractive feature of vinyl windows is their low maintenance. Vinyl windows do not require any exterior maintenance other than washing. Do not paint them; ever, the chemicals in the paint will likely reduce their longevity…and your neighbors will want you drug-tested.
All in all, vinyl windows are a tremendous value. I have had aluminum windows, wood windows and vinyl and I preferred the vinyl windows. It is of course a matter of choice and budget.

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New Trends In Wood Windows

rcovington — Sun, 17 May 2009 04:33:46 +0000

Simply put windows…are what you put in the holes in your house. Think about that. Holes in your house. It seems to me that if you are going to have holes in your house, you want a very good quality window to prevent those holes from letting the conditioned air out and the cold air in and rain from destroying the interior of your house.

There are three basic categories of windows:

Wood
Aluminum
Vinyl

I will discuss wood windows in particular in this post and specifically clad wood windows as very few people wish to put unclad windows in their house due to the added maintenance of having to paint them every 3-5 years. Clad Wood windows are made of wood, (primarily pine) but are sold primarily with a cladding on the exterior to reduce the exterior maintenance requirements that attach to all windows (no painting). The cladding on the clad wood windows is typically Aluminum, however their are increasing options in this regard in the form of extruded and sheet noble metal claddings such as Bronze, Copper and Zinc.

Clad Aluminum Double Hung Window

The last 3 materials are generally sold only on custom windows which are very expensive and typically can only be justified on hard budgets of over $ 400 PSF. If you are like me (and most others) you will not be building a home in this range.

Bronze Clad Door

However, there are a few copper alternatives manufactured by commodity window manufacturer’s that might in fact fit into your budget. I will discuss these in greater detail in a later post. Anyway back to clad wood windows.

Andersen, Pella, Weathershield, Jeld-Wen and Marvin

The best known names in this field (due to huge marketing budgets) are Anderson, Pella, Weathershield, Jeld-Wen and Marvin. They probably comprise about 65% market share between them and each of them have their own specific advantages and disadvantages. Only a careful review of the features and benefits of each window will reveal what is best for your project. A brief description of the features that I consider important when reviewing the various windows follows below:

Anderson – unique in that the wood window made by Anderson is clad with a PVC vinyl cladding. The cladding is bound to the wood substrate with an adhesive type mechanism which has shown effective, but in some extreme climates worries me that it could detach. The window is backed by a top-notch warranty and I have anecdotal experience that the company takes its warranty obligations seriously.

The other features of the window include a proprietary glazing system that will require that you will always have to go to Anderson for replacement and a reticence by the company to put breather tubes in their glazing system (critical in high altitudes). Anderson is the largest manufacturers of windows (under one brand) in the U.S. Anderson sells their product through a dealer network composed of lumber yards, window dealers and home-improvement contractors. Anderson now also sells a line of composite windows made from the waste wood derived from manufacturing its wood windows under the Renewal brand name.

Pella – Pella manufacturers windows, both clad and unclad in Iowa and markets them through primarily authorized distributors although they have recently started to distribute their builder grade line through Home Depot. The Pella product is distinguished by the availability of built-in roll-down insect screens, between-the-glass window blinds and and an exclusive distributorship for the clearest window screening material made in the United States.

Pella’s clad system is roll-formed and loosely attached which can cause problems such as “oil-canning” in very hot climates and the possibility of condensation forming underneath the cladding in high-humidity locales. Overall Pella makes a good quality window. Pella now manufactures a line of composite windows which show promise from a performance perspective.

Jeld-Wen – sells wood windows under a variety of brand names including Jeld-Wen, Pozzi, Wilmar and a few others. All of these brands were more or less regionally well-known brands and Jeld-Wen has made a weak effort to unify the brands either from a marketing perspective or from a manufacturing perspective from what I can tell. The various brands have quality reputations that you will have to judge for yourself. The Jeld-Wen moniker is a holding company for a broad range of construction products that make Jeld-Wen a very large presence in the construction products category, a great many of them in the commodity category. They are an excellent manufacturer. One special feature of Jeld-Wen windows is their Auralast brand of wood preservative treatment. If you select this optional treatment, you will get a 20 year limited warranty against wood rot on the window.

Marvin – is an old line family owned firm that manufactures a broad line of wood windows and composite windows. One of the distinguishing features of the Marvin brand is that the aluminum clad version is actually an extruded aluminum sash with a Wood insert to the interior. This scenario is also a feature of the Weathershield line and the Window Technologies (now defunct as of 5/2008 source: Window and Door Magazine) line in the Midwest. This method makes for a more rigid sash, and eliminates the possibility of oil-canning and reduces the chances of moisture forming under the cladding. It also places a barrier insulating air space underneath the sash which should add somewhat to its performance in cold climates.

An up and coming brand that traces its heritage back over 50 years is Windsor Windows and Patio Doors. Windsor has completely redesigned their product line to an extruded cladding design over the last few years and have focused on high performance windows available with a high degree of customization.

Among all these companies discussed, their is a strong commitment to supporting green building objectives. They have all submitted to the most stringent testing protocols and all of these manufacturers carry Energy Star qualified windows and doors. It will be critically important that you look very carefully at the energy efficiency of the windows that you select.

The cost of installing high-efficiency glazing systems has fallen to the point that the payback is as low as 3-4 years. As energy costs rise, this payback period will shrink lower still. Look for Energy Star qualified windows suitable to the zone you live in. Select those with the lowest U-Value if you live in the colder climes and select the lowest SHGC if you live in the sunbelt. Your home will be more comfortable, you will use 20-30% less energy over clear glass and you might just be able to obtain tax credits from your state or rebates from you local utility to help pay for the upgraded glazings. For more information on glazing systems see the Efficient Windows Collaborative Selection Tool.

These are the (5) largest manufacturers of wood windows in the United States based on market share. The relative value of their products is affected by a range of factors that will make your choice dependent on your specific needs. There are also a great many regional manufacturers, that make good quality windows that will be equally prevalent in your locale.

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