How Much Heat Are You Losing Through Your Old Windows?

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In the winter, your heating bill skyrockets as you pad around your home in wooly slippers and heavy sweaters. In humid Louisiana, you can’t ever seem to escape the heat of summer, especially at night. Sound familiar? If cold drafts plague your winter days and sticky heat makes for sleepless nights, here’s a look at how much energy you are losing (and how to prevent heat loss) through windows.

How much heat is lost through windows? 

It’s shocking how much heat is lost through windows. The most recent data available in a global study conducted by the United Nations found that buildings use 40% of all global energy – and windows use half of that. This means that even for fixed windows on high-rise buildings, heat loss through windows is a significant issue.

On an individual scale, your old, leaky windows could be responsible for 25-30% of your home’s heating and cooling bill. The less efficient the window, the higher your energy bills will be. This thermal image, taken by a professional energy auditor, shows how the warmest air (shown in red) escapes through the windows and doors.

are you losing heat

How is heat lost through windows exactly?

Nearly two-thirds of the loss occurs when heat contacts inefficient window glass. Single-paned windows are the biggest offenders, but this heat loss can occur in older double-paned windows too. As your windows age, you may be paying to heat the air trapped between the inner and outer panes of glass (instead of your home!). The remaining heat loss is due to leaks in the frame and seals of the window itself.

The good news is this: replacing your leaky windows is one of the most effective ways to increase the comfort, value, and energy efficiency of your home.

How to keep heat from escaping through windows

For new construction, one of the first things to consider preventing heat loss through windows is the energy-efficient orientation of your home. In warm climates like Louisiana, plan for a north-south orientation, with windows on the north side of your home.

In a pre-existing home, you still have tons of options to minimize heat loss through windows. An energy audit can help you measure energy loss through your windows before you begin to make changes.

The next step is to select the best windows to minimize heat loss. When picking efficient windows, you should consider a number of different factors.

  • The U-factor: The rate of heat loss for an entire window. Lower U-factors mean more efficient windows with less heat loss.
  • The Solar Heat Gain Coefficient (SHGC): This measures how effectively the window blocks heat coming from the sun. The lower a window’s SHGC, the less solar heat it transmits.
  • Energy Star rating: In the South, humidity is tough on windows. Energy Star-certified windows meet strict efficiency standards and are crafted by certified partners. At LAS Shutters + Windows, our rating exceeds the southern U.S. requirements by 30%.

One of the ways windows minimize heat loss (and keep your home cool in the steamy Louisiana summers) is by using low e-glass. This energy-efficient window glass is coated with thin layers of metallic material that prevents heat from entering (or leaving) through the glass. Low e-glass glass reflects 40 to 70% of the sun’s energy back where it came from so your home stays cooler in the summer. It can also reduce heat loss through windows by as little as 18% or as much as 30% when properly fitted and installed.

Soft coat low e-glass performs at a much higher level when it comes to blocking infrared light. LAS Shutters + Windows exclusively uses this type of glass in our windows because it is ideal for southern climates with high air conditioning usage.

Windows Made For Your Home

Investing in custom windows is another way to prevent heat loss through windows. Some new construction is built to a template that automatically fits standard window sizes, but this is not always the case. In many of the historic homes in Louisiana, you’ll rarely find a well-fitted “off the rack” window. Custom-crafted and properly installed windows not only enhance the look of your home but also save you money on energy bills and increase the comfortable enjoyment of your home.

These changes don’t just make you feel good—they save you money, too.

In 2020, the Efficient Windows Collaborative (EWC), a coalition of government agencies, research organizations, and manufacturers that promote efficient window technology, found that homeowners in Louisiana’s climate can save up to $541 a year (.pdf) with the most energy-efficient types of window.

If you choose a high-quality window and have a well-qualified, professional, experienced company install your windows, you can expect from 25% to 52% savings on your energy bill. For example, investing $10,000 in replacement windows could save you 40% of your annual $3000 bill, or $1200 a year.

Not only will your savings make up for the cost of your new windows, but you will also experience a more comfortable home with enhanced beauty and value.

Invest in your home

Your home is likely your largest investment. Protecting it with energy-efficient windows brings one of the best returns on your investment. This is one remodeling project (.pdf) that appeals to both buyers and sellers of new construction and historic homes alike.

More than that, though, is the year-round comfort and pleasure of having an efficiently heated and cooled home. Minimizing energy loss through windows means that you and your family can enjoy every room in the house, all year round.

At LAS Shutters + Windows, we custom-craft and expertly install windows, shutters, doors, and siding, using materials and methods designed for the Gulf South’s unique climate. With over six decades of experience and “Best of Home” awards since 2016, we are ready to provide you with extraordinary service and high-quality windows.

Get in touch for a free estimate today

Posted in: Buyer's Guide Doors Energy Efficiency Home Improvement Windows

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