Every replacement window comes with an energy rating label from the National Fenestration Ratings Council (NFRC), an independent testing laboratory that measure the performance of windows and doors. (“Fenestration” means “opening.”) If the window you are buying from a Bay Area replacement window contractor does not have an NFRC label, walk away!

Among the most important measurements when it comes to energy efficiency is the U-factor of a window. In order to make an informed decision when buying replacement windows for your home, you should have an understanding of this rating.

You may be familiar with a measurement called “R-factor” for insulation. This is a rating given to insulation in walls and ceilings. The biggest difference between U-factor and R-value is that U-factor measures the rate of heat transfer (or loss) while R-value measures the resistance to heat loss.

R-value is a measure of conductivity. A product with high conductivity will transfer heat quickly, like a hot pan on the stove or a single pane of glass on a cold day.

U-factor, on the other hand, takes into account more than conductivity. It also is affected by the airflow around the window and the emissivity of the glass. Emissivity is the ability of a product to absorb certain types of energy (specifically infrared) and radiate that energy through itself and out of a room.

A product with high emissivity, such as one pane of clear glass, will transfer over 84 percent of the infrared energy from a warm room outside to the cold air. The lower the conductivity and emissivity of the glass, the lower the rate of heat loss and the lower the U-factor.

There have been significant technological developments over the last 10 years involving low emissivity (low-e) coatings on the glass. There are now many glass products available with these low-e coatings, which are typically used in dual pane windows and insulating glass units.

The key, then, is to look for a window with a low U-factor rating, showing that the window has low emissivity.

At SaveEnergy, you’ll find the NFRC label on all of our replacement windows. It shows that the replacement windows we install across the Bay Area have among the lowest “U-Factor” of all windows tested by the NFRC. The lower the U-value, the greater a window’s resistance to heat flow and the better its insulating value. That means SaveEnergy’s windows are among the best for energy efficiency, keeping you warmer in winter and cooler in summer.

For more information about upgrading the windows in your Bay Area home with energy efficient replacement windows call us toll-free at 800-728-3878.

Despite Mr. Twain’s cheeky comments, winter is the time the Bay Area can get really cold. And experts predict the winter of 2010-2011 may be among the coldest in recent memory.

AccuWeather predicts that San Francisco will have temperatures about 1.5 degrees cooler than normal. TheWeatherSpace.com is predicting extremely cold air masses will move into the Western part of the United States, with a dominating Northwest flow in the upper levels the dominating pattern in the Western US all season, a reason for the colder than normal temperature forecast.

Are you ready for a “colder than normal” winter? Brrrrrr! The best way to stay warm amid our Bay Area winter is to make sure your home is buttoned-up against the cold. Otherwise it is going to be months of wearing extra sweaters and listening to the furnace kick on again… and again.

Did you know that almost half of the warm air your home’s heating system produces is lost through leaky, draft windows and doors? The windows in most homes that are 10 years old or older almost universally fall far below the current standards for energy efficiency, allowing the easy transfer of heat energy from your home to the outside; and cold temperatures from the outside in.

SaveEnergy installs highly efficient replacement windows that are engineered to put a virtual stop to this heat loss. Using high-tech materials and design, including multiple glass panes with inert gas fill and warm-edge spacers, our windows can cut energy loss by more than 30%.

That translates two ways. First, it means you will be warmer inside your home and can put your sweaters away! Equally as important, installing energy-efficient windows from SaveEnergy means that you can significantly reduce energy use, which results in a “quieter” heating system and lower monthly heating bills, all winter long.

For more information about upgrading your windows with energy efficient replacement windows call us toll-free at 800-728-3878.

Want to make your San Francisco Bay Area home more comfortable while saving money every month? You’ve come to the right place! For more than 25 years, family-owned Save Energy Company has been the replacement window contractor your Bay Area neighbors have chosen to help them select the perfect replacement windows and doors for their homes.

Save Energy Company offers homeowners in Petaluma, Sonoma, Marin, Novato and San Francisco a wide range of energy efficient replacement windows and doors, to reduce your home’s environmental impact while lowering your monthly energy bills. All while adding beauty, comfort and value to your home.

Our name says it all: Save Energy Company can help you reduce your energy costs while making your home more comfortable, beautiful and valuable — effortlessly, affordably and dependably! How reliable is SaveEnergy? Our contractor’s license number is the same one we started with in 1983 and has never changed: 440356!

Call us toll-free 1-800-728-3878 for a FREE in-home estimate.

Check out our Video Testimonials page.

Diamond Certified has a mission to define excellence and identify the highest-quality local companies for consumers in the San Francisco Bay Area. Save Energy Company has passed a rigorous survey of real customers and earned the prestigious Diamond Certified award, signifying that we have risen to the top of our field. Our entire team is dedicated to ensuring you have confidence in choosing us as your premier window and door company.

What the value of Diamond Certified is to the consumer:

Each Diamond Certified company has been rated Highest in Quality in the most accurate ratings process anywhere in the San Francisco Bay Area. We support consumers with our Diamond Certified Performance Guarantee. www.diamondcertified.org/guarantee.