Use U.S. NFRC Ratings

To Compare

Replacement Windows

Determining the thermal performance of a replacement window may seem like an overwhelming task, but the U.S. government has established standards to make it easier. Energy Star is a federal government program that sets standards of energy efficiency for many products including replacement windows. They require that replacement windows are tested using criteria set by the National Fenestration Rating Council (NFRC). Results of this testing are available at the NFRC website and on stickers supplied with every new Energy Star window.

U-Factor

Every window sticker includes a rating for the U-factor. This is the best single indicator of the insulation value of a replacement window. The lower the number, the higher the insulation value. To establish the U-factor, NFRC tests windows at multiple points around the glass and frame. When comparing replacement windows, ask to see the NFRC ratings, not the center of glass measurement that some manufacturers promote. Center of window glass measurements always produce  better results than NFRC ratings but are not a true indicator of real world performance and should not be compared to NFRC ratings.

The lowest priced vinyl windows have u-factors around .50 and are about half as efficient as Betterliving Crusader windows. Most mid-priced vinyl windows have u-factors that are about 20% - 25% less efficient than Crusader windows for about the same price. Other window manufacturers must use expensive krypton gas fill or triple pane glass to match the performance of Betterliving replacement windows with Sashlite technology.

Condensation Resistance

The NFRC also tests for window condensation resistance. With this measurement, a higher number means greater resistance to condensation buildup on the interior surface of glass and frames. Better living Crusader windows have a condensation resistance rating of 61 placing them in the range of triple pane windows or windows made with more expensive exotic frame materials.

Solar Heat Gain Coefficient

The Solar Heat Gain Coefficient (SHGC) is an indication of how much heat in the form of infrared light the window will allow to pass through. The best SHGC number depends on the climate where you live. In Connecticut with our hot summers and cold winters, a mid-range SHGC is typically best.

Visible Transmittance

VT is a measure of the amount of visible light that passes through the window glass. Replacement windows with triple pane glass or two layers of low-e coatings typically have lower visible light transmittance and can darken the interior of the home.

Design Pressure (DP) Rating

The design pressure rating is a measure of how well the window resists water and air infiltration in a simulated storm environment. This rating is rarely included on NFRC stickers. The Better living Crusader window has a DP 55 rating which means it is certified to withstand winds of 182 mph. This is one of the highest ratings of any replacement window in America and it exceeds the DP requirements for windows in the most stringent coastal hurricane locations.

Air Leakage

This is an indicator of the amount of air leaking through the window assembly. Few manufacturers publish this measurement because windows may be tested at different wind speeds depending upon their DP rating. Replacement windows with low DP ratings are measured at lower wind speeds and might produce better air leakage results even though the window assembly actually leaks more than a window with a high DP rating. If both windows were tested at the same air speed, replacement windows with higher DP ratings would usually produce better air leakage results.

How to Improve Window Performance

Frame Design

The energy efficiency and NFRC ratings of replacement windows are partially determined by the quality of the frame. Multiple chambers and foam filled frames produce the best thermal performance. Frames are important but the window glass package has the biggest impact on efficiency. Double pane glass provides a dead air insulating layer that approximately triples the insulation value of single pane windows.

Argon Gas Fill and Triple Pane Glass

Manufacturers gain additional insulating performance by replacing the air between the panes with a non-toxic inert gas such as Argon. Some replacement windows provide even greater performance by using krypton gas or adding a third pane of glass creating two dead air spaces, but these solutions have drawbacks. Triple pane windows are heavier. The added weight makes them more difficult to clean and places greater strain on the moving parts. Triple pane windows reduce the visible light transmittance and darken the interior of the home. Three panes of glass requires two sets of spacers. This doubles the risk of seal failure. If the gas leaks out, performance will diminish and you might never know. The biggest problem with krypton filled or triple pane replacement windows is the VERY high cost - if windows are too expensive, you will never save enough money in reduced energy costs to return your investment.

Low-e Coatings

Low emissivity (low-e) coatings provide another method of improving window performance. These coatings contain powdered metal that acts to reduce the amount of ultraviolet (UV) and infrared (IR) light entering the window while having minor impact on visible light transmittance. UV light fades carpet and fabrics. IR light heats the interior of the home, increasing air conditioning costs and making some rooms uncomfortable. Low-e window coatings also help to retain heat inside the structure by reflecting IR back into the house. Window glass with low-e helps to lower air conditioning costs in the summer and reduce heating bills in the winter. Having the right type and quantity of low-e for your climate is important. More is not always better. Too much low-e can darken the view through your windows. Some low-e coating are oriented toward hot climates, some toward cold climates, and some are balanced for a four season climate. Better living replacement windows use Solarban 60 low-e because it provides performance balanced for Connecticut 's four seasons.

Spacer Bars

Another component that effects window performance are the spacers that separate the panes of glass and seal in the gas. Until the introduction of Sashlite technology, these spacers were made of metal or foam with a thin film. Metal spacer bars conduct cold, increasing the possibility of condensation and reducing the insulation performance of the window. Foam spacers utilize a microscopically thin membrane to seal in the gas. They provide better thermal performance than metal spacers but the membrane is susceptible to damage during manufacturing, installation, and everyday use. Even pinhole size damage will allow the gas to leak, reducing the insulation value of the windows. Utilizing revolutionary manufacturing and sealant technologies, Betterliving eliminates conventional spacers and attaches the glazing directly to the vinyl sash. Metal used in conventional spacers conducts heat 80 - 1300 times more effectively than vinyl, so windows with metal spacers will lose heat more rapidly than Betterliving windows with Sashlite technology. Since they do not rely on a fragile thin film to seal in the argon, replacement windows with Sashlite are far more resistant to damage than windows with foam spacers.

Better living Crusader replacement windows are constructed with double pane glass to eliminate the problems and reduce the expense of triple pane windows. They feature Solarban 60 low-e coating which provides an excellent balance for the Connecticut climate between air conditioning and heating performance. Argon gas fill provides enhanced thermal performance without the high cost of other gasses. Revolutionary Sashlite window technology eliminates spacers and surpasses the thermal performance of both metal and foam spacers without the potential for damaged membranes in foam spacers. How do the ratings compare for the Better living Crusader replacement windows with Sashlite technology?

Triple Pane Performance

At a Double Pane Price!