Replacement Window FAQ

Here are some of the top questions we get for Replacement Windows from our Houston area clients

Window Styles and Features

Replacement Window Terms and FAQ

Photo Credit: Angie’s List

  1. What does Double Hung Mean? Double hung windows have two sashes and are arranged vertically. Both sashes operate meaning that the lower sash slides up and the upper sash slides down. The benefits of double hung are the ability to vent the room from the top of the window by opening the upper sash a little. This is safer than opening the lower sash when considering where burglars and prowlers enter a home.
  2. What is a Vent Lock? Vent locks are integrated lock mechanisms that prevent the window from opening past a vented position. This is also a safety precaution against break-ins and unauthorized entry.
  3. What is a Tilt Sash? Double and single hung windows offer a tilt sash feature which is a locking mechanism that allows the sash to tilt in when unlocked. This is safe and very convenient for cleaning the outside glass surface from inside the home. Removal of the sashes for repair/replacement/cleaning is also possible after tilting the windows in. Always be sure to re-lock the window tilt locks after use.
  4. What is the Super Seal? The SuperSeal is the rubber spacer in between the surfaces of the glass around the perimeter edge. It keeps the two glass surfaces separated creating an air gap. This makes heat transfer nearly impossible between the exterior and the interior glass. In many cases, the air gap is filled with an inert gas such as argon to increase the insulating property of the window.
  5. What is SHGF or SHGC? These acronyms are for the Solar Heat Gain Co-efficient or Factor. This is an NFRC (National Fenestration Rating Council) standards of measurement. Energy Star recognizes these standards. The SHGF is the window’s ability to reduce the effects of solar heat passing through the window and heating up the interior of the home. Doors and skylights are also rated this way. Energy Star recommends a .25 number here but the numbers can be much more efficient than this. The lower the better in hot climates. .16 is even possible. In colder climates where you want the heat from the sun…say Minnesota, you want higher numbers. But for replacement windows in Houston, stay as low as possible.
  6. What is the UF or U-Factor? This is another NFRC number (see SHGF for explaination) but this one rates the window’s ability to keep your home insulated. That means keeping the heated air in during the winter and keeping the cool air in during the summer.
  7. What is Low-E? Low E or Low Emmissivity refers to the amount of UV light that is reflected off of the windows so that the light can not penetrate the window and fade your fabrics. It is a light, invisible oxide coating on the interior surface of the glass. There are two main standards: 2/70 and 3/66. The first number represents the number of coatings applied. Either 2 coatings or 3 coatings. The second number is the amount of visible light allowed into the room. 70% and 66% respectively.
  8. What is an Oriel Window? When windows are over 60″ or so, the sashes become too heavy to utilize a double hung design. In this case, the window size will be divided up, usually about a 60/40 split with the upper sash being the larger and becoming a fixed sash. Essentially, an oriel window is a single hung window with a larger proportion dedicated to the top sash.