Frequently Asked Questions

Answers to frequently asked questions regarding vinyl windows, energy efficiency, window replacement and more.


How do vinyl windows compare with windows made from other materials, such as wood and aluminum?

Vinyl is today’s most popular choice for window material. The maintenance free and energy efficient benefits of vinyl are second to none. Since the mid 90’s, however, the popularity of vinyl has sky-rocketed due to the cosmetic and design enhancements that have been added to vinyl products to distance them from the other composite choices.


How do Ellison windows compare with other vinyl windows?

Ellison offers comprehensive product lines in both new construction and replacement markets. Ellison offers just about every style window available and has good-better-best price points that allow any home to be upgraded or built with Ellison products.


What does it mean that Ellison windows and doors pass AAMA and NFRC tests?

AAMA is an industry organization that independently establishes structural standards for manufacturers to meet and exceed. Most brands of windows will be tested and labeled with an AAMA sticker.

NRFC is the trade organization related to the energy efficiency of windows and doors. If a brand does not proudly state its membership to each of these organizations, then a consumer should question the absence. Please go to each organizations website for more information.

AAMA website:

NFRC website:


How do I know when I need to replace my existing windows?

That’s up to you as a consumer. When you are tired of painting, or tired of dealing with that fog between your panes, or those incredibly high power bills in the summer and winter, or the air you feel when you walk by a window, you may need to consider replacing them.

Please recognize, a lot of the cost of heating and cooling your home may be off-set by the incredible energy efficiency of new, Energy Star compliant vinyl windows.


What does R-value and U-value mean?

R-Value is a term that measures the insulation properties of a material. For example, fiberglass insulation is measured by its “R-Value.”

The energy efficiency of windows is measured by “U-values.” Because windows are not insulators by design, they cannot be measured in “R-Values.” However, windows obviously have insulating properties, so there needs to be a measurement that allows comparison of styles and window packages.

There is a relationship between R-values and U-values. Whereas the higher the R-value, the greater its insulating ability, the lower a U-value, the better that product’s insulating efficiency is. To find a U-value, divide the number “1” by the R-value. For example, an R-value of “4” is equal to a U-value of .25.


What is ENERGY STAR? What qualifies your products?

Energy Star is a national campaign sponsored by the E.P.A. and the Department of Energy to promote energy-efficient products. The endorsing logo may be found on computers, appliances, power tools, etc. Any product that uses or affects energy may have an Energy Star rating.

All Ellison products with Low-E glass and Argon insulating gas are Energy Star compliant anywhere in the country. Although the organization has divided the country into zones with separate criteria, Low-E and Argon will render every Ellison product compliant in all regions.

For more information, please visit the Energy Star web site at:


Can I order a window or door to fit any opening?

Yes, however, in some cases you might have to order multiple windows to fill one opening. Some openings are just too big and may require multiple windows joined together in order to fill the opening. There are standard window sizes that accommodate the majority of applications, but many openings will require custom sizing. The same applies to doors. Some openings will require a standard door size with custom sized transoms or side-lites to make the opening appear correct.

The best suggestion is to consult a replacement window dealer or professional contractor. With some imagination and consultation, even the most complex and large opening may be fitted with a replacement window…it’s just that some configurations may require more than one window, door or combination.


What is insulated glass? Why does Ellison use it?

Insulated glass is two panes of glass separated by an insulating spacer. This provides optimum energy efficiency and allows options to be added to a window’s glass package.


What is condensation? What causes it? Is it covered under warranty?

Condensation is a result of warm or humid air making contact with a cooler surface. Condensation on the outer panes of a window—either outside of your home, or the inside of the home—is normal and shows the window is doing its job. Condensation between the panes of glass indicates a seal failure and may or may not be covered by warranty depending on the coverage period. Ellison offers a range of seal failure warranties, ranging from a pro-rated 25-year period to a pro-rated lifetime coverage period. You can view our warranty details by visiting the Warranty section of our website.


What is Low-E glass?

Low-E glass stands for low emissivity glass. Made during the manufacturing process of the raw glass, low-e is not a film, rather it is a component in the surface of the glass. The actual ingredients in low-e glass vary from type-to-type, but the basic premise is the same: low-e glass reflects heat away. During summer, it reflects heat away from the house and during winter months it reflects the heat generated by a furnace back into a home.

Ellison uses a low-solar gain low-e with a double coat of silver (also referred to as a “soft-coat” low-e).

To learn more about glass visit the Glass section of our website.


What is Low-E glass with Argon Gas? How does it work?

Added inside an insulated panel with low-e glass, Argon gas is an invisible, insulating blanket that replaces most of the air during the manufacturing process. With low-e reflecting heat away, Argon gas buffers thermal transfer to enhance the performance of the whole glass panel.


What kind of maintenance will my Ellison windows require?

The good news is they will never require painting. When you see dirt or unwanted film on the glass, just use a gentle glass cleaner and wipe clean. With grids between the panes, it’s that much easier. When you see outside sills and vinyl collecting dirt or getting dingy, just wipe clean with a gentle cleaner and soft rag, or just use water and a rag.


Where can I buy Ellison windows?

We sell exclusively through a network of the country’s top exterior building supply distributors. The ones specified on this site in the Distributor Locator section will give you a resource in your area. Most of these companies do not sell to the general public, but they may offer excellent suggestions and refer you to a great dealer in your community.


How can I get more information and literature about Ellison products?

These same distributors can answer specific product knowledge questions and provide to you literature and other product information.


How do I become an Ellison dealer/distributor?

Please submit your inquiry to Ellison Windows and Doors, PO Box 1869 Welcome NC 27374; Attention Director of Sales.

The Ellison Windows 101 Video Series

Window Styles 101

Window Anatomy 101

Window Options 101

Window Warranty 101

Window Condensation 101

Windows 101 General Codes

Windows 101 Coastal Codes

Wood Window Opening Installation 101

New Construction Installation 101

Window Measuring 101

Ellison Product Care

Ellison windows and doors are designed for easy care and maintenance. Click the button below to download Ellison’s window and door care and maintenance guide

Download Guide

Understanding Condensation

Condensation is a direct result of interior humidity and the difference between indoor and outdoor air temperature. Click the button below to download our Understanding Condensation guide for windows and doors.

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Looking for ENERGY STAR qualified products? Learn more about the climate zones and performance criteria used to identify ENERGY STAR compliant windows and doors.