Which Replacement Windows Are Most Energy Efficient?

Did you know that old, decaying windows can let up to 40% of the heat in your home escape? Naturally, this leads not only to less comfort, but also to increased heating and cooling bills. Energy efficiency should be one of your top concerns when you think about buying new replacement windows – getting the right ones can help you save up to 20% on your energy bills.

The first thing you need to know about the energy efficiency of windows is that it is measured by the U-factor. This factor can range from 0.15 to 0.30 and, the lower the number, the more heat your windows will retain. Ideally, you should look for a U-factor that is no higher than 0.26, especially if you live in an area that is prone to extreme weather.

To make things easier for you, here is an overview of the most energy efficient replacement windows you can find on today’s market:

Windows With Multiple Panes Of Glass

If you want multiple panes of glass, you can choose between:

• Double-pane glass: this type of window is filled with inert glass and it is almost twice as energy efficient as the single-pane units.
• Triple-pane glass: these are the perfect replacement windows for people who want their home to be extremely energy efficient. With these windows, you get the best U-factor and very little energy lost. However, before ordering them, you should know that they can also get quite pricey – from $50 to more than $200 per window. This is why budget conscious homeowners often upgrade to triple-pane glass only in the areas of the home that are most prone to energy loss – the southern side of the house that takes full day sun exposure is the perfect example here.

Glass Panes Filled With Argon

Placed between the panes of glass, this gas adds extra insulation to your windows. And, don’t worry, it is a colorless, non-toxic, natural and inert gas that poses no threat to you. If you want extra efficiency and reduced bills, argon-filled glass panes are an affordable solution.

ENERGY STAR Certification

Some people like the heat, but dread the cold, while others would gladly spend their lives in an Alaskan environment. If you prefer either of these, why pay for extra insulation options? Check out the main energy efficiency options below and choose only the ones that suit your needs:

• U-factor: should be between 0.15 and 0.26
• Air infiltration: should be .05 or lower,  it measures the amount of air that can be leaked through a window
• Solar heat gain coefficient: its recommended value is .25 or higher for climates prone to cold weather. This measures how much your home can be heated by the sun through the glass.
• Visible transmittance: should be no less than .50 for double pane windows and higher than .40 for triple pane. It measures the amount of light that enters your home through the glass.
• Condensation resistance: should be 65 or higher, it measures your windows’ capability to resist condensation.
• Design pressure: should be 50 or higher,  it measures the structural integrity of the entire window unit.

Foam Filled Windows

Filling the frames and sashes of the windows with foam reduces their thermal conduction and increases the efficiency.

Before ordering your replacement windows, make sure that you work with a reputable contractor for their installation. Energy efficiency is not just about the materials used in the windows, but also about their proper installation. If the most energy efficient window in the world is installed improperly or poorly, it will not perform as expected and the results will be disappointing.