We've taken the questions we most often hear from homeowners like you and had our engineers and experts answer them—to help you learn more about windows and doors. The questions below have been organized into categories for your convenience. Click on any of the questions below to view its answer.

How do you know when you need new windows? What is a replacement window? What are the advantages of custom replacement windows over pre-made, standard-size windows stocked at home centers and lumber yards? Do replacement windows really pay for themselves or is that just a sales line? Aren't beautiful vinyl windows an oxymoron? How are replacement windows any different from older windows in terms of cleaning? Will new windows eliminate condensation? ENERGY EFFICIENCY What makes a window or door energy efficient? What is an R-value and how important is it in selecting windows? What is a U-value? What is Low-E and, how important is it to have it on your windows or doors? What is ENERGY STAR®-and what does it have to do with windows and doors? What is the NFRC and what should I know about it? Does argon or krypton gas between glass panes really make a difference in energy efficiency? How important is weatherstripping? What are the different types of weatherstripping, and what benefits do each have? What causes condensation on windows? Do windows cause condensation? Where on a window does condensation normally form and why? Can I reduce the condensation on my windows? What steps can I take to reduce humidity in my home? What is ENERGY STAR®?

How do you know when you need new windows?

• Your home feels drafty in cold weather or uncomfortably hot from heat penetrating in warmer weather.
• Your heating and cooling bills are high-and keep getting higher!
• Your home's existing windows are faded or cracked, making your home look old, dated or in poor condition.
• Your windows are difficult or impossible to open or close.
• You're spending far too much time working on your old windows-scrubbing, painting, puttying and re-caulking them.
• You're planning to sell your home and know your current windows will lower the re-sale value of your home.

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What is a replacement window?

A true replacement window is a window that's custom built to fit within the opening of an existing window. It's built to fit precisely and can be installed without disturbing the interior and exterior areas around the window.

What are the advantages of custom replacement windows over pre-made, standard-size windows stocked at home centers and lumber yards?

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Because custom windows are made to fit perfectly, they provide the best energy efficiency (which saves energy costs) and install much more easily and with very little mess. Also, because of the myriad of options available that affect appearance and efficiency, custom windows allow consumers to design exactly the windows they need or want. Standard windows typically cost less in the beginning, but other expenses and factors-like additional labor and the disruption to the home-far outweigh the original savings. For example, installing stock windows requires that you add brick or siding to the exterior, and drywall or other materials to the interior. In addition, custom-made windows allow you to choose the best solution to the problems you want to solve by replacing windows.

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Do replacement windows really pay for themselves or is that just a sales line?

It's true, if you select high-quality, energy-efficient windows. Savings will vary, but expertly engineered and well-built windows lower home energy consumption. With vinyl-framed windows, maintenance is also virtually eliminated. No need to scrape and paint windows.

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Aren't beautiful vinyl windows an oxymoron?

Years ago that may have been true. However, today-with the options available and with advances in window design technology-quality vinyl windows are both beautiful and unique. For example, home owners can choose from sculptured or sleek window styles; white, almond or woodgrain vinyl finishes; standard or diamond grids; and beveled, leaded, etched or stained glass. And these are just a few of the options available. There are still old fashioned, low-end vinyl windows available, but the new designs are beautiful, maintenance-free and energy efficient.

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How are replacement windows any different from older windows in terms of cleaning?

Many high-quality windows are actually engineered to make cleaning easier. For example, double-hung windows with the latest internal constant force balance system allow a home owner to easily maneuver the sashes up and down. They tilt in-and lock securely in place-for safe, easy cleaning. Quite a difference from old wood or aluminum windows that stick and are difficult to move up and down.

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Will new windows eliminate condensation?

Actually, no. Condensation is moisture vapor suspended in the air, and that's something no one can guarantee to eliminate. However, high-quality vinyl windows incorporating warm-edge technology glazing systems will help to reduce condensation because they're much less thermally conductive than other window types. They can help keep the temperature of the window warmer-minimizing the hot and cold differences that turn moisture into condensation.

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ENERGY EFFICIENCY

What makes a window or door energy efficient?

Numerous factors, including how the frame and sashes are engineered and built, the type of glass used (single-, double- or triple-pane), the weatherstripping, the type of low-emissivity coating on the glass and the presence of argon or krypton gas.

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What is an R-value and how important is it in selecting windows?

Although the U-value is actually the important number in evaluating windows and doors today, most people are more familiar with the related concept of R-value (or R-factor). The R-factor of a window is the measure of its resistance to the transfer of heat flow. The higher its R-value, the greater its insulating ability.

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What is a U-value?

U-value (or U-factor) is the measure of the window's ability to conduct heat-in other words, the amount of heat transmitted through the window. The lower a window's U-value, the better the window is at insulating your home.

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What is Low-E and, how important is it to have it on your windows or doors?

Low-E stands for low emissivity and is a fairly new advancement in glass technology. Basically, it's a microscopic, metallic coating-applied to a surface of glass-that reflects and re-radiates heat energy either into or out of a home depending on climate conditions. Using Low- E is an excellent way to increase the energy efficiency of a window. In fact, it's so effective that every Weather Tamer window with Low-E is ENERGY STAR®-compliant in every region of the U.S.

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What is ENERGY STAR®—and what does it have to do with windows and doors?

ENERGY STAR® is a U.S. government program-administered by the Department of Energy and the Environmental Protection Agency with the cooperation of manufacturers-that's designed to reduce the consumption of fossil fuels through the education of consumers. The program covers many different types of products. Windows and doors can only carry the ENERGY STAR® label if they are tested by an independent laboratory through the NFRC program and meet specific, predetermined U-value ratings. By selecting ENERGY STAR® products, you will reduce your energy costs and help make the environment cleaner.

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What is the NFRC and what should I know about it?

NFRC stands for the National Fenestration Rating Council. It's a program established by the U.S. Department of Energy to help consumers compare window products and options. Window manufacturers participating in the program are required to label every window to its specific thermal performance level. Customers are then ensured that the products they select meet the requirements for their application. Participation in the NFRC program is voluntary. Not all manufacturers participate because it requires outside third party inspection and extensive product testing.

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Does argon or krypton gas between glass panes really make a difference in energy efficiency?

For air to insulate well, it needs to be as still as possible because moving air carries energy. Both argon and krypton are heavier than air-so they're less prone to convection or thermal movement. The bottom line is that heavier-than-air gases offer a higher level of insulation. Both argon and krypton are found naturally in the air you breathe and are completely harmless.

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How important is weatherstripping?

Very. Weatherstripping is important because it provides the barrier against air and water in windows and doors. It is the only element of operating windows or doors that make them reasonably air tight. High-quality weatherstripping that's applied and compressed properly really does improve the insulating performance of windows.

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What are the different types of weatherstripping, and what benefits do each have?

Although there are many different types of weatherstripping, they basically fall into one of three categories-woven piles, flaps, and hollow or foam bulbs. Which is best? That depends on the window style, design and application. Windows and doors that are expertly engineered-like Revco's-are designed with weatherstripping that creates the tightest possible seal and holds up to time and heavy use.

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What causes condensation on windows?

Whenever there is excess humidity in a home, it manifests itself in the form of condensation on the coldest area of a wall, which is normally the windows. The warmer the air, the more moisture it will retain, so when air in your home comes in contact with the colder glass surface, it is subsequently cooled and moisture is released in the form of condensation on the glass.

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Do windows cause condensation?

No, condensation on windows is not the fault of the window. However, by replacing drafty windows and doors or installing a new roof or siding, you are reducing air flow in your home and making it tighter. Tighter homes actually retain more humidity.

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Where on a window does condensation normally form and why?

Condensation often forms at the meeting rail and at the bottom of the lower sash on the interior of the glass. This is because when warm air cools, it falls down across the interior surface of the window at the same time the air's temperature is falling. The air contacts the horizontal surface of the meeting rail, which acts like a dam, slowing the air's rate of fall and creating the perfect opportunity for the trapped water vapor to escape and form on the meeting rail's surface. The air then rolls over the edge of the meeting rail and again gains speed until it encounters the lower handle of the sash. At this point, the water vapor again makes its exit and lies at the bottom of the sash.

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Can I reduce the condensation on my windows?

Yes. In order to reduce condensation, humidity must be controlled and air movement must be generated. As the exterior temperature drops, the humidity level needs to decrease if condensation is to be controlled.

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What steps can I take to reduce humidity in my home?

The two main things you can do are to control sources of moisture and increase ventilation. To decrease or control excess humidity and condensation:

• Use exhaust fans in your kitchen, laundry and bathrooms.
• Vent gas burners, clothes dryers, etc. to the outdoors.
• Shut off furnace humidifiers and other humidifying devices in your home.
• Be sure that the ventilating louvers in your attic, basement or crawl spaces are open and amply sized.
• Open fireplace dampers to allow an escape route for moisture-laden air.
• Air out your house a few minutes each day.

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What is ENERGY STAR®?

If you want to save money on your heating and cooling bills-and ensure your home is as comfortable as it can be-then you will surely be interested in windows and doors that are ENERGY STAR® qualified. The ENERGY STAR® label can be affixed only to windows and doors that meet specific U-value and shading coefficient ratings for one or more regions of the U.S. These ratings are achieved through independent testing done to NFRC* standards. Practically all Weather Tamer vinyl windows and doors that incorporate any of Revco's numerous low-emissivity high performance insulating glass systems meet ENERGY STAR® requirements and therefore are ENERGY STAR® labeled.

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* National Fenestration Ratings Council, a federal program created to establish standardized testing procedures and ratings of window and door products.