Gallery: How to Green Your Home With Windows From Marvin Windows Expert...


Over the last few weeks our exclusive Green Home Expert editorial series has brought you a bounty of tips on how to green your home with advice from the greatest green minds in architecture, interior design, and home energy. While the last four installments of the Green Home Expert Series have focused on bigger picture alterations you can make to green your home, our last article will focus on one of the most important elements to maintaining a green home: windows! Windows aren’t just a portal to the outside world — they can improve the comfort of your home, the interior light and ambiance, the ventilation, and above all, they can dramatically increase your energy savings. Joining us this week is Marvin Windows Expert, Christine Marvin, who is among the fourth generation to work for the family-owned and sustainably operated made-to-order window and door company. Christine provides us with a wealth of knowledge, giving us her top 5 considerations for transforming our homes with new windows.

TIP 1: Consider All Factors: Climate, Energy, Design & Style

When considering an investment such as changing windows, customers have many decisions to make. For many individuals, aesthetics may be the first thing that comes to mind – which window best matches the design of my home? If I choose this model, will it stick out like a sore thumb? These questions are completely justified and customers shouldn’t gloss over any of the details, but at the same time, it’s just as important to think about energy efficiency, light emissivity, and how window choices may help you heat and cool your house too. Other factors to consider are craftsmanship, how well specific windows conceal interior fasteners, functionality, ease of use, and what goes into maintenance.

But if you really want to get into the nitty-gritty of greening your home through windows, the number one consideration is going to be window performance. Standards for performance often come listed on a manufacturer’s label, where makers list performance data that can arm you with the information you need to make intelligent comparisons between products and manufacturers depending on your needs and location.

TIP 2: Know Your Climate – Where You Live Impacts What You Should Buy

The next question you might ask is, “How do I know which energy considerations are suitable for me?” The region in which you live plays a crucial role in deciding which window is the right product for you. In particular regions, certain glazing options are better than others in maximizing comfort and energy efficiency.

In Northern zones where the weather is cold, triple-pane glass is a great option for enhanced thermal performance — i.e. for keeping warmth from leaking our of your windows. There are also windows available in an array of dual-pane coatings that extend comfort during winter months while maximizing solar heat gain coefficients to block heat loss and reflect heat back in from the outside.

Alternatively, in Southern climates or sun-intensive areas where weather conditions remain mild year-round, you definitely want to look for windows that help keep excessive solar heat out of your house during the summer. In these locations, choosing a window with a lower NFRC Solar Heat Gain Coefficient (SHGC) is your best bet. It’s also very important to take note of where your windows are positioned with respect to the day’s sun and your surrounding landscaping (such as trees).

Your local climate will also have an impact on what sort of coating your windows should have. The industry standard for energy-efficient glass coatings has become Low-emissivity (LoE or Low-E) coatings. LoE coatings are microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a window or skylight glazing surface, primarily to reduce excessive solar heat gain through windows – or the U-factor – by suppressing radiant heat transfer. Coating selected glass surfaces with various Lo-E coatings can block a significant amount of heat transfer, reducing your home’s need for energy-sucking air conditioning. Lo-E coatings allow visible light to pass through without allowing infrared light (i.e. heat) to pass through the glass. Think of Low-E coating as a film of microscopic blinds and you’ll have a better understanding of how it works.

Some examples of common LoE coatings for various zones include:

LoĒ-179™ (High SHGC Low E): Features a single metallic coating and an insulator that blocks heat loss to the outside and reflects heat back into a room. This glass is often used in passive solar applications because it allows the winter sun’s heat to pass into the home. This type of coating is particularly useful for those living in cold climates.

LoĒ2-272®: Features a double metallic coating on the inside glass surface to reflect heat into the room in winter and reject the sun’s warmth in summer, reducing damaging UV rays. This glass offers an enhanced U-factor and solar heat gain coefficient.

LoĒ3-366®: Features three metallic layers of silver. This glass rejects more solar heat and is recommended for warm climates where cooling costs are high and intense exposure to the sun is an issue.

Triple-pane: A high-level of energy efficiency is achievable through triple-glazing and filling the interior spaces between the panes with Argon, or – for an even better insulating value – a blend of Krypton and Argon gases. Triple-pane glazing is also available with various LoE coatings to fit a variety of climate requirements, particularly in northern regions, but it works well in the southern regions as well. Typically, triple-pane glass boosts window durability in colder climates by reducing the amount of condensation and the duration of condensation on the glass. Triple-pane has the potential to significantly improve your U-factor while saving on energy costs.

TIP 3: Understand the Label – Performance Rating Information

Energy-efficient products are now highly sought-after by homeowners, whether for new construction or for renovation. The introduction of new regulatory programs and ENERGY STAR’s new 2010 criteria point to the growing importance and recognition of energy efficiency in every part of our built environment — be it in household appliances, windows, or doors. Currently, there are a few prime gauges of performance that can be found on your window’s labels. Every label highlights the various characteristics and performance factors of your window, such as whether or not a window is dual-pane or has a specific U-factor. Generally these labels will come in three flavors:

1. Manufacturer’s Rating

Often a manufacturer will generate its own ratings, which will sum up many common areas of concern such as energy savings, solar heat gain, light transmission and more. However this isn’t always enough information to make a decision as to whether or not the window is appropriate for your home. Manufacturers often apply their own standards, which can in fact vary significantly from company to company, making it extremely difficult to make just comparisons between different products. To make sure that you are properly evaluating all of your options, you should shop with a manufacturer that uses a third party rating system such as ENERGY STAR or the National Fenestration Rating Council (NFRC), which have fixed measurements for window appraisal. Third-party certification by a reputable organization, such as NFRC, brings confidence that the product’s performance values have been replicated and validated by an independent source.


By now most of us are familiar with the ratings provided by ENERGY STAR, particularly when it comes to everyday household appliances and electronics. ENERGY STAR-rated windows can lower your household energy bills by 7-15 percent, potentially reducing green house gas emissions from power plants and shrinking your home’s carbon footprint. ENERGY STAR is the trusted, government-backed symbol for energy efficiency that was established with the goal of helping consumers save money and protecting the environment by promoting energy-efficient products and practices. ENERGY STAR is subject to rigorous standards set by the Environmental Protection Agency (EPA) and while exact energy savings will vary, on average, ENERGY STAR rated windows have revealed savings of several hundred dollars annually.*

There are four zones in the U.S. (and four more in Canada) with differing ENERGY STAR performance criteria, which are based on location and optimal performance for your region. For example, windows in the North are optimized to reduce heat loss in the winter, and windows in the South are optimized to reduce heat gain during the summer. But you don’t have to wait to see these values after you’ve purchased your windows. If you need more information on exactly what it means to be ENERGY STAR rated and what numbers are relevant to you, simply go online, and you’ll find that any reputable company’s website will provide you with the proper literature, as well as listings for local dealers that can discuss the rating system with you. Asking important questions up front will help you optimize your windows for your specific needs – so don’t be shy with your queries!

*Estimated savings are based on data set forth in the US Department of Energy’s Energy Star Savings Estimates, available here. Actual savings will vary by product type and configuration, location and method of installation, individual home characteristics, local climate and conditions, utility rates, and other factors. For additional information, visit ENERGY STAR’s website.

3. National Fenestration Rating Council (NFRC)

You should always seek out a manufacturer that works with the NFRC to rate product energy performance. NFRC is an independent, non-profit organization that has established an energy performance rating system for accurately comparing different window and door products. Some factors considered in creating a window or door’s rating include: the U-factor, the solar heat gain coefficient, visible light transmission, and WDMA design pressure ratings. The values achieved through NFRC testing can be seen on the window and door label that leaves the factory and/or on a manufacturer’s website or in the technical documents.

Unlocking the Mystery Behind the Label

Every label lists several performance values: the U-factor, the solar heat gain coefficient (SHGC), the visible light transmittance value (Vt) and a design pressure rating (DP). Here is a quick explanation of each of these terms:

NFRC U-factor: The U-factor tells you the window’s rate of heat loss and how well it insulates. The lower the number, the better a product is at keeping heat inside a building and the better its insulating value.

NFRC Solar Heat Gain Coefficient (SHGC): The SHGC tells you how well a product blocks heat from the sun. This is an important value – just think, someone in Arizona will certainly have different solar heat gain coefficient needs than someone in Minnesota!

NFRC Visible Light Transmittance Value (Vt): The Vt is a measure of how much visible light passes through the window and door. Be aware that the values shown on the label are for the entire unit – glass-only values will be much higher. However, different types of glass and coatings have different visible light transmittance values.

WDMA Design Pressure Ratings (DP): The DP measures the amount of pressure a door or window will withstand when closed and locked. Each DP rating also establishes other performance factors such as water penetration, air infiltration, structural pressure, forced entry, and operational force. The higher the DP numbers, the better the performance. Look for the Hallmark certification of the Window and Door Manufacturers Association. DP is particularly relevant to energy performance because it contains information regarding certain air infiltration thresholds.

TIP 4: Make Sure Your Windows Are Under Warranty

Owning a home requires continuous upgrading and updating to ensure that you are not only creating a comfortable environment for ourselves, but protecting your investment. Window replacements are very much a part of this long-term investment, so you should be certain that you are installing a product that is of the highest quality and value – this can often be signaled by the type of warranty your manufacturer offers.

A window is usually covered by a warranty for performance under normal operating conditions, and most reputable manufacturers will cover your investment with a limited warranty against defects in manufacturing, materials, and workmanship for up to 10 years from the purchase date. Certain components may be warrantied for even longer. Marvin, for example, provides a 20-year warranty on their insulating glass that covers visible obstruction caused by a failure of the insulating glass air seal.

You should also make sure that the installer’s workmanship is covered by a separate warranty, so that if they accidentally break the insulated glazing, you should be covered by the installer’s warranty. Also note that installation errors may not show up for a few months, so be prepared for such an incident. Finally, keep in mind that warranties can be used for marketing purposes – you should always read the fine print carefully to see exactly what you are getting and for how long.

TIP 5: Look for a Company With Values That Match Your Own

If you take all the tips above into consideration,it’s easy to see that picking the right company to source your windows from is just as important as the windows themselves. Look for a company with heritage, a proven track record, and a commitment to bringing you the best products and services. Determine what is important to you as a customer and what values you look for in a business’ operations. Make a list of all these characteristics and find a manufacturer that mirrors your values – whether you value innovation, quality, energy efficiency, or doing what is right. Remember that you are making an investment that is meant to last, and you should have confidence that your window will be there with you until the end.

Marvin Windows Expert – Christine Marvin

Christine Marvin manages a team of product planners at Marvin Windows and Doors. With an undergraduate degree from Macalester College and an MBA from the University of Denver, Christine is among the fourth generation of Marvins to work for the family-owned and operated made-to-order window and door company. Marvin’s team of product planners always are researching and looking at the latest technology and innovation, with a focus is on providing windows that lead the industry in performance and design.

Green has become a mainstream concept in the building industry, which means that the latest energy efficient window solution isn’t solely intended for an early adopter, but for all homeowners interested in reducing their energy bill consumption and improving the efficiency of their homes. Marvin is a great example of a window company that is dedicated to bringing their customers the best on the market. As a family-owned business in its 4th generation – founded in 1912 – Marvin focuses not only on the quality of their product, but their community and the environment.

The company has made a commitment to the environment by sourcing lumber from reliable suppliers and offers chain-of-custody, SFI and FSC certified wood, and has always understood the importance of making homes more energy-efficient with products that lead the way in thermal performance. Marvin was the first to offer Low-E glass on its entire product line, and this sense of innovation and commitment to performance continues. Additionally, Marvin’s role in the community has always been at the core of its operations – even during the recession, Marvin refrained from making any layoffs, and today they continue to maintain a growing staff.

Some of America’s most energy-efficient LEED showcase homes feature the very same Marvin windows that you can buy for your own home. Marvin believes in building top performance into windows and doors with proven technology that are accessible to the average homeowner. And the proof is in the numbers: Marvin has more than more than 150,000 window and door products that are ENERGY STAR certified. More than 80 percent of the existing U.S. housing stock was built before 1990. Replacing old, inefficient windows and doors is one of the best ways to increase America’s overall energy efficiency.

To see how beautiful, efficient Marvin window and doors can become part of your home, sign up for Marvin’s online remodeling planner. This free planner helps you visualize space, track budgets and create an inspiration board.


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  1. carole Maloney April 21, 2011 at 12:19 pm

    Thanks for the explanations on the various low E offerings!

  2. fezguru April 18, 2011 at 11:18 am

    Great article on greening your home through windows. To add a note, I’m from Miami and an excellent way to lower your power bills and increase your safety is through hurricane impact windows. They are double paned and filled with argon gas (if I remember correctly) which greatly reduces heat entering your home while protecting you from burglary and high winds. Some insurance companies will also lower your rates if you have them although they are terribly expensive to acquire to begin with.

  3. vijfab April 15, 2011 at 3:52 am

    I am interested in your products. Will you please guide me?

  4. madeline taylor March 28, 2011 at 9:57 pm

    I have a passive solar home . Lots of heat 45 degrees this time of year, late March, on my window sill. Plants are doing well while outside it has been cold with snow on the ground. Check out elemental designs .ca to see a picture of my home.The one built on a curve.

  5. Kestrel Jenkins March 16, 2011 at 2:35 pm

    Stellar explanation of labeling, and what it means for us as window-purchasers.

  6. Rebecca Paul March 16, 2011 at 2:33 pm

    Great tips Christine! This is really informative.

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