Home >> energy efficient windows

Tag Archives: energy efficient windows

Low E Barndominium Windows

Being a life-long baseball fan, my first introduction to “Low e”, was former Mariner, Ranger, Angel, Indian, Blue Jay and Tiger relief pitcher Mark Lowe, who could chuck a rock as high as 101 miles per hour!

OK, not so funny, but it does illustrate how little I (and most people) knew or understand about low e windows.

For decades most post frame buildings were either cold storage, or rarely heated structures. With more and more post frame buildings being used as climate controlled homes, barndominiums and shouses (shop/houses) more efficient windows are needed, if not required.

What exactly is low e glass? Here are a few key technical terms about low e glass:

Low-emissivity: Low e glass coatings work by reflecting or absorbing infrared light and ultra-violet rays. A window with low e glass does a better job of keeping heat in during winter and out during summer.

U-factor measures how easily heat flows through a product. Lower numbers keep heat or cold exactly where you want it. Each state has its own set of U-factor ratings within its Building Codes.

Solar Heat Gain Coefficient (SHGC) tells how much heat radiation – due to sunlight – a window lets in. If heating your barndominium is your main concern, a higher SHGC can help offset some heating costs. In warmer climates, where air-conditioning costs are a bigger factor, look for a lower SHGC number.

Windows manufactured with low e window coatings typically cost about 10-15% more than regular windows, however these windows can dramatically reduce energy loss by as much as 30–50%.

A low e glass coating is a microscopically thin, virtually invisible metal or metallic oxide layer deposited directly on surfaces of one or more glass panes. This low e window coating reduces infrared radiation from a warm pane of glass to a cooler pane, thereby lowering U-factor. Simply put, a lower U-factor equals a more energy-efficient window.

Different types of low e glass coatings have been designed to allow for high solar gain, moderate solar gain, or low solar gain. A low e coating can also reduce a window’s visible transmittance (visibility through glass) unless you use a spectrally selective coating. Spectrally selective coatings are optically designed to reflect particular wavelengths but remain transparent to others. Such coatings are commonly used to reflect solar spectrum’s infrared (heat) portion while admitting a higher portion of visible light. They help create a window with a low U-factor and solar heat gain coefficient but with a highly visible transmittance.

Spectrally selective coatings can be applied on various types of tinted glass to produce “customized” glazing systems capable of either increasing or decreasing solar gains according to aesthetics and climatic effects desired.

All new windows have National Fenestration Rating Council technical labels applied, making it easier to understand above information.

If you live where heat/cold fluctuations are minimal, low e windows are probably not high on your list. Living here in Northeast South Dakota where summers hover around 100 degrees and winters -20 to -40, you can bet low e windows are always on my shopping list when constructing a new post frame building.

This entry was posted in Pole Barn Structure, Windows, Post Frame Home, Barndominium, Shouse, Pole Barn Planning and tagged low-E windows, low E glass, energy efficient windows, Solar Heat Gain Coefficient, U factor windows, spectrally selective coating on April 28, 2020 by admin.

Windows and Daylighting

Daylighting

Windows are more than just a building’s eyes to the world. Properly located they can also save on your pole building’s utility bills as well as increasing comfort and productivity.

Windows Daylighting is the use of nature’s sunshine, rather than bulbs, to light interior spaces. Many variables need to be considered to maximize the benefits. These include types of windows, their placement, location of interior spaces and control of how much light comes in. All of these factors add together to create properly lit and energy saving spaces.

Geographical location and climate, building architecture, use and orientation are big factors in designing a successfully daylit building. Such a building is always the result of a combination of art and science, engineering and architecture.

Windows with southern exposure let the most light in during the winter and less in the summer. North facing windows are good for daylighting as they let in natural light with little glare and little summer heat.

East and west facing windows provide little in the way of daylighting other than in mornings and afternoons, however generally contribute glare and excess heat in summer months.

Clear glass actually provides 140 to 200 times the light required for indoor work spaces!

This extra light creates glare and a cave effect – where the rear of rooms appear dark compared to other surfaces. When this occurs, the blinds start being closed, lights are turned on and the electric meter begins to turn. In properly designed spaces the windows are appropriate to provide enough, but not too much light. The use of light colors on ceilings assists in defusing and adding to the effects of day light in any room.

In most cases, electric lights, which produce a lot of heat, do not need to be used during daytime hours. Natural lighting, properly designed, produces little or no heat, provides adequate lighting of work spaces and decreases internally generated heat – resulting in the need for smaller HVAC systems, reducing upfront costs, which can be used to improve daylighting systems.

To reduce glare, overhangs can be placed above windows, which also cuts down on summer heat gain, Inside, louvers or tinting reduce glare and can be used to properly direct light to where it is best utilized.

Modern window technologies are also more energy efficient than the single glazed (one pane of glass) aluminum frame windows I grew up with. Low-E and gas filled double and triple pane windows insulate, while allowing in wanted light.

And, like those Ray-Ban sunglasses, special windows are available which lighten and darken with the amount of sunlight!

In new pole building construction, proper daylighting can be accomplished without increased construction costs and the benefits of lower lighting costs and reduced cooling costs.

Best of all natural lighting has proven psychological benefits for the building’s occupants!

This entry was posted in Uncategorized, Windows and tagged pole building windows, energy efficient windows, daylighting on July 30, 2015 by admin.

Energy Star and Windows

Ever wonder where the whole “Energy Star” thing started from? It seems like it pops up on everything from computers to refrigerators to windows.

Well, the Energy Star program was started in 1992. It is a voluntary program, which lets manufacturers put an Energy Star label on specific items if they meet certain EPA (Environmental Protection Agency) set efficiency standards.

For two decades, the Energy Star program has guided consumers to reasonably priced energy-saving windows and doors. Now, the EPA’s mindless pursuit of tougher energy efficiency standards threatens it.

The program in itself has been a success. Especially amazing for one involving not only the government, but even more astounding the EPA. According to the EPA, since 2000, Americans have bought about 3.8 billion Energy Star-rated products, saving $230 billion in energy costs and preventing 1.7 billion metric tons of greenhouse gas emissions.

Over time, the EPA has tightened its Energy Star standards, as technology has allowed for more efficiency gains without adding much in cost.

But in its zeal for ever greater energy efficiency, the EPA now plans to impose new standards for windows which will add significantly to their price, putting Energy Star-rated windows out of reach of most consumers.

In colder climates, the new standard would likely require expensive triple-paned windows, the industry warns. In an early draft, the EPA admitted it would add an average $20 to Energy Star-rated windows.

While this might not seem like much to Washington bureaucrats, those higher prices will surely scare away cost-conscious consumers, thousands of whom wrote to the agency complaining about the proposed changes.

The Home Depot, which knows something about what consumers will pay for home improvements, explained to the EPA its new standard would, if enforced, “take the Energy Star program from an affordable stretch for our customers to an unaffordable rejection.”

Lowe’s noted it would take several years, if not decades, for consumers to recoup the added costs of those more expensive windows. Lowe’s said it would likely cut its Energy Star offerings if the EPA enforces the new standard.

Either way, the result will be fewer consumers buying Energy Star-rated windows. So, instead of cutting energy use, the EPA’s move will have the opposite effect — making it both bad for consumers and the environment.