If you've ever stood next to a window in winter and felt cold air coming off the glass, you might have wondered if it's time to invest in energy efficient windows. Old windows leak heat in the winter and let it in during the summer, so your furnace and air conditioner end up doing the extra work.

"Energy efficient" gets used a lot, so it's hard to know what it really means or whether these windows are worth paying for. Here's a quick guide to how they work, what kind of savings to expect, and how to choose the right ones for your home.

What are energy efficient windows?

Energy efficient windows are designed to slow down heat moving in or out of your house. Better insulation means your heating and cooling system runs less, and the rooms near your windows feel more comfortable.

When we say, "energy efficient windows," we usually mean windows that meet ENERGY STAR® standards for your climate zone. That label tells you the window has been tested and rated for how well it performs where you live.

When we say, "energy efficient windows," we usually mean windows that meet ENERGY STAR® standards for your climate zone. That label tells you the window has been tested and rated for how well it performs where you live.

What makes a window energy efficient?

It's a combination of features, including:

• Number of panes: Older windows often have a single pane of glass. Energy efficient ones typically have two or even three, with a small, sealed gap between the layers that helps slow down heat transfer.
• Insulation performance: This is measured by the “U-factor,” which tells you how well a window keeps heat from escaping. A lower number means less heat loss.
• Frame type: Newer frames use insulating materials that help keep heat in during the winter and out during the summer.
• Gas fills: The gap between the panes is often filled with a gas, usually argon. It's denser than regular air, so it insulates better.
• Quality construction and installation: Even a great window won't perform if it's installed poorly. Air leaking around the frame can cancel out a lot of the energy savings.

How much do energy efficient windows save?

The short answer is "it depends."

ENERGY STAR® estimates the average savings for a typical home in our region at several hundred dollars a year. If your current windows are already decent double-pane units, the savings will be smaller.

Your home's size, your utility rates, and how well the windows are installed all play a part, so think of any number you see as a ballpark. And the savings are only part of the picture. Most people also notice fewer drafts, steadier temperatures, and a quieter house.

How to choose the right energy efficient windows

A few things to look for when you're comparing options:

• The ENERGY STAR® label for your region. Windows that suit a warm climate aren't the best fit for a Wisconsin or Minnesota winter, so make sure the rating matches where you live.
• A low U-factor. In cold climates, this is the number to pay attention to most. Ask what the ENERGY STAR® requirement is for your zone and make sure the window meets it.
• Frame material and style. Vinyl is popular because it insulates well and is low maintenance.
• Who's installing them. Ask how they seal and insulate around the frame and what the warranty covers.

Signs it's time to replace your windows

If you've noticed any of these, it may be time to consider new windows:

• You feel drafts coming through the window even when it's closed.
• You see condensation or fog between the panes, which usually means the seal has failed.
• Your windows are hard to open, close, or lock.
• There's visible rot, warping, or cracking in the frames or glass.
• Your heating and cooling bills are creeping up.
• Some rooms always seem too hot or too cold.

Ready to talk windows?

Picking out windows is a big decision, and you shouldn't have to figure it all out on your own. Contact River Valley Remodelers to schedule your free in-home design consultation. We'll look at what you've got now, talk through your options, and help you find windows that fit your home and your budget.