About Kensington - FAQs

Frequently Asked Questions

• How do vinyl windows compare with fiberglass windows? I was told fiberglass windows are a better product, because they are stronger.
• Can you paint vinyl windows?
• How is the fuel savings on the fuel savings pledge calculated?
• I bought my Kensington Windows from a company that is no longer in business. Is my window warranty still good?
• How do I get parts for my windows?
• Can I buy windows directly from Kensington?
• Can you provide me a price on a particular size window?
• What if there is not a Kensington dealer in my area?
• The dealer told me your windows have an R-25 rating, is that true?

How do vinyl windows compare with fiberglass windows? I was told fiberglass windows are a better product, because they are stronger.

Here's a brief comparison of vinyl windows versus those made from fiberglass.

• The great "strength" that the fiberglass guys talk about (they usually say that it's 9 times stronger than vinyl) is actually its tensile strength. Tensile strength is a measure of how much force it would take to deform a lineal if you grabbed it at each end and tried to pull it apart. While it is true that fiberglass lineals have very high tensile strength, a window lineal is never put under any kind of stress where tensile strength is even a factor.
• All of the strength in a fiberglass lineal comes from the amount of glass in the lineal. Therefore, a higher glass content percentage equals greater strength. Most fiberglass window lineals have about 50% glass content. In a standard welded vinyl window, each sash profile is attached to a panel of 100% glass and each frame profile is attached to the building structure! Whether you're talking about fiberglass, vinyl, or any other framing material, the glass itself is what gives the window its strength, not the lineals.
• The more glass content you add to a fiberglass lineal (to increase its strength) the more you decrease its thermal performance. We all know that plain glass is a very poor insulator.
• Vinyl is actually a much better insulator than pultruded fiberglass. Most people equate fiberglass with insulation value, but you need to remind them that the type of fiberglass they're thinking of has virtually nothing in common with the type of fiberglass that's used in a window frame. The 14" thick blanket of pink glass fibers that they see in their attic is designed to trap small pockets of warm air and it does a good job of it. The compacted fiberglass used in window frames can't trap any air and therefore is not nearly as good of an insulator. As a matter of fact, fiberglass window lineals actually transfer 3 to 4 times as much cold as an equivalent vinyl lineal. We've all seen the graph showing the measure of heat loss in BTU's per hour of different window framing materials. Wood has a factor of 1.2, vinyl is 1.4 and aluminum is 1400 plus. The equivalent factor for fiberglass is about 4.8. Since most people buy windows to reduce their energy costs, it is easy to see why vinyl is a far better value.
• Like most hard materials, fiberglass is very brittle. It can crack and chip very easily.
• Since the materials used in fiberglass resins are not UV stable, all fiberglass lineals (even white ones) have to be painted. Because they are painted, they are very prone to scratches during assembly, shipping and installation. Nearly every fiberglass window you see has been "touched up" to cover the nicks and scratches. These touch-ups are done with a brush or spray can and the paint is not the same kind of paint that the lineal is originally painted with. The original paint is a two-part formula that includes weathering agents, hardeners, etc. These types of paints cannot be mixed ahead of time for use as touch-up paints.
• Because they have to be painted, fiberglass windows are not nearly as maintenance free as vinyl windows.
• Many fiberglass guys show a copy of an outdated Department of Energy report that makes fiberglass look very good and refers to vinyl as "weak". This report has been updated at least twice since its original printing and is now much more favorable to vinyl. Look on the Department of Energy website for the correct and current report.
• Fiberglass windows cost nearly double what a good vinyl window costs, and they are less thermally efficient. On a cost/benefit or "payback" basis, a person is much better off spending money on an upgraded insulated glass package if they want a premium window that is actually better. We all know that roughly 80% of a windows area is insulated glass anyway. The frame material is of little significance. And, for the 20% of the window are that is made up of the framing material, vinyl is better!
• In general, vinyl windows have better NFRC and Energy Star ratings than fiberglass windows. Since these are independent third party ratings, they are very significant in determining which window material is actually better.
• Regardless of what material they're made from, sooner or later, all mechanically fastened windows leak at the corners and all fiberglass windows are mechanically fastened! My personal experience confirms that service issues with fiberglass windows are MUCH more frequent and severe than with vinyl windows. Trying to "screw and glue" a thin-walled hollow shape on a consistent basis is almost impossible. You can take a corner sample of any "super strong" fiberglass window frame and break it easily with your bare hands. You can stand on a welded vinyl frame corner with no ill effects. The inability to weld fiberglass is a huge problem.
• Owens Corning, the largest fiberglass company in the world and the inventor of fiberglass windows, gave up on them about 5 years ago. Even though the Owens Corning window was a sound design on paper and was backed by the resources of a billion dollar global corporation, it was a complete and total failure. When the Mother of All Things Fiberglass drops fiberglass windows, you know there are serious problems. Owens Corning sell welded VINYL windows today.

Can you paint vinyl windows?

Vinyl windows are the most popular replacement windows in the U.S. because of two main reasons, they never need painting, and they are energy efficient. Even though vinyl is designed to be maintenance free, we always get questions about painting the vinyl surfaces.

Most vinyl window companies will void their warranty if a homeowner attempts to stain or paint the window. Kensington states this case clearly in its' warranty. The warranty will be voided because many paints contain solvents that may damage or weaken the vinyl materials that make up the window. Some Kensington window systems are available in white, tan, and a selection of interior wood grain laminates. These colors and simulated wood grains were chosen because they tend to blend in with the majority of interior decorations and colors. We strongly suggest you do not try to paint your vinyl windows.

How is the fuel savings on the fuel savings pledge calculated?

The method of calculating your fuel savings is very complicated. The summary below will give you an overview on the steps we take to determine your savings.

The most important aspect of calculating energy savings is that energy consumption is used in the equations, not energy cost. Since we cannot possibly control the costs of oil, coal, natural gas, or any other heating fuel, all of our calculations are based on consumption and not cost.

Also, we need to determine what portion of energy was used for activity other than heating and cooling. Since our windows only reduce energy used to heat or cool a home, we must determine what portion of energy consumption is consumed by other power users (televisions, hair dryers, cooking, lighting, etc.).

We use three data sets in our calculations:

1. Monthly energy bills for the year prior to window replacement.
2. Monthly energy bills for a year after window replacement.
3. NOAA heating and cooling degree-day tables.

NOAA (National Oceanic and Atmospheric) is a government organization that produces Heating and Cooling Degree Day tables for each of the fifty states. These tables show how much heat and cooling is required to maintain a comfortable indoor temperature. A Heating Degree Day of 20 means a heating system must produce enough heat during the day to maintain a 20-degree difference between the indoor and outdoor temperature.

To determine the amount of energy used for purposes other than heating a home, we look at the fuel consumption for the month with the lowest Heating Degree Day number. An example of this would be August in St. Louis. The Heating Degree Day number for this month is zero. This means the heating system is not required to maintain an indoor temperature during the entire month. We assume the natural gas used during this month is used for purposes other than heating the home (hot water heater, cooking, etc.). We make the assumption that this amount of energy is consumed each month for non-heating purposes.

We determine the amount of energy for cooling in a similar manner. We find the lowest Cooling Degree Day month and assume the energy consumed during that month was not used for cooling the home.

We then add the total amount of energy used for the entire year. The total yearly estimated amount of energy used for purposes other than heating and cooling is subtracted from this total. The result is the total amount of energy used for heating and cooling purposes. By comparing this total before window replacement and after window replacement, we can calculate the amount of fuel saved by installing new vinyl windows.

I bought my Kensington Windows from a company that is no longer in business. Is my window warranty still good?

Kensington stands behind the warranty of the window even if the company that sold you the window is no longer in business. Review your warranty for details on what is covered by the warranty. Should you need to make a warranty claim, click on the Contact Us tab and the words "Warranty/Service". Fill in the form completely and click the SEND IT button. You can always call our Customer Service Department at 800-444-4972.

How do I get parts for my windows?

If you need glass or window components for your Kensington Window, click on the Contact Us tab and the words "Warranty/Service". Fill in the form completely and click the SEND IT button. You can always contact our Customer Service at 800-444-4972.

Can I buy windows directly from Kensington?

Kensington sells through specialty window dealers and distributors. These professionals are best equipped to service and install your windows. If you are a dealer or contractor and would like to become a dealer, click on the Contact Us tab and the words "Become a Dealer." Fill out the form completely; click on SEND IT and our Sales team will follow up in the near future.

Can you provide me a price on a particular size window?

Many factors go into pricing a window installation. Without seeing your particular situation, we are unable to give you an accurate price for installing our windows. For example, removing a steel window from a masonry opening is much more difficult than extracting a wood double hung from a stud opening. Plus, older homes may have damaged surroundings that need replaced or updated prior to installation. Therefore, we will refer you to a dealer or distributor in your area, to obtain an accurate quotation.

What if there is not a Kensington dealer in my area?

Email us your zip code and we may have a new dealer coming to your area in the very near future. We are constantly adding new dealers in many states and the web site may not have been updated at the time of your search. We'll do our best to find an appropriate outlet to buy our windows.

The dealer told me your windows have an R-25 rating, is that true?

You can find the performance rating of each window system by using the "Performance Tests" tab in the "Windows" section. Some people get confused about these ratings so there is a description for each one on the chart. R-25 is the rating of the foam-filled frame and sash alone. There are many other factors involved in determining the R-value for the entire window unit, such as the type of glass and style of the window.