A Closer Look at Today’s Energy Efficient Windows

Posted by on Jun 27, 2017 in Uncategorized | Comments Off on A Closer Look at Today’s Energy Efficient Windows

If you want to improve your home’s energy-efficiency – and save money – one of the most impactful changes you can make is to replace your windows. This is because older windows are often responsible for a great deal of unwanted heat transfer. In summer, inefficient windows can let excessive heat into your home; in winter, inefficient windows allow heat to escape.

Today’s high-efficiency windows are much better at managing heat transfer – reflecting away heat in the summer and trapping heat in the winter. When heat transfer is managed, you’re more comfortable – and less heating or air conditioning is required to keep you that way. And when your heating and air system gets a rest, your pocketbook does, too.

Let’s take a closer look at how energy-efficiency windows work – and how much money they can save you:

Energy-efficient windows, such as these from Richmond’s replacement window experts, feature advanced low-e (low-emissivity) glass coatings. These coatings are designed to emit low levels of heat, reflecting the sun’s infrared heat rays away rather than allow them to pass through. These low-e coatings are quite effective; while standard glass absorbs more than 80% of infrared rays, low-e glass absorbs a third. Despite their effect on infrared rays, low-e coatings won’t compromise your window’s view or the natural light that you love.

Modern windows also employ two or sometimes three panes. Each extra pane provides an extra buffer, adding a layer of insulation between your home’s interior and exterior. Gases such as argon or krypton are often injected between the panes; these gases are clear, non-toxic, and odorless. More importantly, argon and krypton conduct heat only half as well as regular air, providing a stronger barrier to heat transfer.

Even the spacers between the panes of glass play an important role in energy efficiency. Not so long ago, spacers were made of aluminum – a metal that conducts heat very easily. Instead of metal, the newest spacers are made of foam. Because foam can expand and contract without losing integrity, it offers longer-lasting seals. And because foam blocks heat transfer, it offers excellent insulation.

When glass coatings, extra panes, gas fills, and spacers work together, windows can be very efficient. This efficiency is most commonly measured along two metrics: U-factor and solar heat gain coefficient (or SHGC). U-factor refers to the heat transferring quality of the glass; lower U-factors mean less heat transfer. SHGC reflects the amount of sunlight that penetrates into the house through the panes; lower SHGC values mean less light.

Windows with the right U-factor and SHGC values for the local climate can be certified by ENERGY STAR as being energy-efficient. In the Richmond area, we live in what’s called the North-Central Climate Zone – characterized by cold winters and hot summers. Here windows require a U-factor of 0.30 or less and an SHGC value of 0.40 or less qualify for ENERGY STAR certification.

So what can you expect if you replace old windows with new ones that have ENERGY STAR certification? In our South Atlantic region, we can expect to save about $450 per year when upgrading from single-pane glass and $59 per year when replacing double-pane glass. To learn more about your projected savings, visit ENERGY STAR.

Replacing your windows is an investment that provides excellent returns in comfort and energy savings. If you’re still living with single-pane or older double-pane windows, now would be a great time to consider an upgrade.