Measuring whole window performance today is all about how much energy savings a window can provide after it’s been installed. From installing brand new windows to replacement windows, it is important that you know the quality of what you are getting. Every window has a different feature and you may be looking for certain ones. In that case, assessing a window’s whole performance is necessary.
Skyline Windows, a trusted local window replacement company, discusses some of the metrics involved in assessing whole window performance for you to know what to look for.
- U-Factor (U-Value)
A window assembly’s capacity to resist heat transfer is referred to as U-Factor (U-Value). It measures the rate of heat loss of a window assembly. The lower the U-Factor, the greater a window’s resistance to heat flow and the better its insulating properties. Most double-pane windows today can have a U-factor of 0.30 or lower. If you live in a region with warmer climates, a low U-Factor is an excellent factor to consider when choosing fiberglass window replacement.
- Solar Heat Gain Coefficient (SHGC)
This metric is measured as the fraction of incident solar radiation that is admitted through a window, both directly transmitted and absorbed and subsequently released inward. The Solar Heat Gain Coefficient is expressed as a number between zero and one. Essentially, the lower the window’s SHGC, the less solar heat it transmits. Some radiation absorbed by the frame will also contribute to the overall window solar heat gain factor.
- Air Leakage (AL)
Cracks in the window assembly are the leading cause of heat loss and gain. It is expressed as the equivalent cubic feet of air passing through a square foot of window area. The lower the AL, the less air will pass through cracks in the window assembly. An AL rating of 0.30 or less is required for ENERGY STAR certification.
- Visible Transmittance (VT)
The VT is an optical property that indicates the amount of visible light transmitted. Many modern windows have spectrally selective coatings so when it comes to composite window replacement, measuring the fraction of visible light transmitted through the window is important.
- Condensation Resistance (CR)
Condensation Resistance measures how well a window resists the formation of condensation on the inside surface. CR is expressed as a number between one and 100. The higher the number, the better a product is able to resist condensation. CR is meant to compare products and their potential for condensation formation.
When it’s time to replace your windows, you’re going to want as big of a selection to choose from as possible. Skyline Windows has four different material options and when you make your choice, you’ll have an experienced, knowledgeable, full-time employee handling the work.
For your free, no-obligation consultation, call (804) 575-7996 or complete our online request form.