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Current Board Posts

  • Wednesday November 26, 2014

    How do I make this window square?

    I just installed my first replacement OKNA window. I took my time, checked for plumb level and square (or so I thought). Everything...

  • Sunday November 23, 2014

    Replacement window over very thin aluminum frame

    I am installing my first vinyl replacement window over an aluminum frame (stucco wall). In all the instructional videos and the instructions that...

  • Saturday November 22, 2014

    Reynolds Vinyl Window

    I purchased Reynolds Vinyl Windows in 1996 and they have condensation in most of them. I was told to get the model number...

  • Thursday November 20, 2014

    Warranty question

    Do lifetime/double-lifetime warranties for the best vinyl manufacturers (like Okna) typically cover only the product or do they cover labor as well? For...

  • Thursday November 20, 2014

    Simonton 5500 spec questions

    I am putting an addition on my house and have decided to use a Simonton 5500 window. I am in Orlando, FL...

  • Wednesday November 19, 2014

    How to test the quality of a window?

    When companies bring vinyl window samples to your home (or when you're in a showroom), what kinds of tests should a consumer do...

  • Tuesday November 18, 2014

    Schuco aluminum commercial tilt and turn window repair

    how do i replace the multipoint latch gearbox on a commercial schuco tilt and turn...

  • Monday November 17, 2014

    Which is the most reliable replacement window on a budget???

    Hi All,
    I'm new to the forum, have been reading up for days, and was hoping for some individual...

  • Monday November 17, 2014

    any suggestion for the vinyl windows?

    Hi, i live in IL and i am planning to replace the aluminum windows to vinyl windows.one contractor quotes the 23 double hung...

  • Saturday November 15, 2014

    Cold weather window caulk recommendations

    What are some quality window caulks that would be ok for sub 40 temperatures? I live in MASS, and the temps here have...

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Do it Yourself- Replacement Window Video

 

Rating Window Efficiency Systems

 

When looking at different models of windows you want to be cognizant of the rating that the manufacturer applies. That rating will either be a “U Value” which gives an indication of that windows tendency to transfer heat either in or out, or by an “R Value” which describes the windows resistance to transferring heat in or out.

U-Values are a measure of heat conductance

R-Values are a measure of heat flow resistance

 

If a window's R-value is high, it will lose less heat than one with a lower R-value. Conversely, if a window's U-value is low, it will lose less heat than one with a higher U-value. In other words, U-values are the reciprocals of R-values (U-values = 1/R-value). NOTE: Most window manufacturers use R-values in rating their windows.

Usually, window R-values range from 0.9 to 3.0 (U-values range from 1.1 to 0.3), but some highly energy-efficient exceptions also exist.

When comparing different windows, you should ensure that all U- or R-values listed by manufacturers:

  • Are based on current standards set by the American Society of Heating, Refrigeration, and Air-conditioning Engineers (ASHRAE)
  • Are calculated for the entire window, including the frame, and not just for the center of the glass
  • Represent the same size and style of window

5 factors affecting the R-value of windows

  1. The type of glazing material (e.g., glass, plastic, treated glass)
  2. The number of layers of glass
  3. The size of the air space between the layers of glass
  4. The thermal resistance of conductance of the frame and spacer materials
  5. The "tightness" of the installation (i.e., air leaks-- see previous discussion).