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What Makes a Minneapolis Replacement Window Energy Efficient?

If you’re concerned about the energy your Minneapolis home uses, chances are you’ve been considering ways to reduce energy use and cut your utility bills.  A great way to do that is to replace your existing windows with more energy-efficient models.  (There are other reasons as well, such as minimizing your carbon footprint and converting to a greener lifestyle, but in this post we’re going to focus on what goes into making a replacement window energy efficient.)

A variety of factors goes into making a window energy efficient.  Some may even work in conjunction with each other to enhance that function.  But here are the basics:

  • Window frame material:  Some materials used to manufacture window frames do a better job at insulating than others.  According to the U.S. Department of Energy, fiberglass window frames (such as the ones we install from Marvin) have what they call ‘superior thermal performance’ due to the air-filled spaces in the frames.  And unlike wood or vinyl, they remain structurally stable despite temperature changes.  That means they will not shift, warp, or shrink.  Wood is a great insulator, but as it ages it is notorious for shrinkage. So that window that fit snugly in its opening when it was first installed eventually becomes loose, letting air in (and out).  That’s one reason we recommend owners of historic homes that have their original wood windows install acoustic storm windows to cut out air loss and heat transfer.
  • Number of glass panes: Today’s replacement window standard is double paned glass.  Old windows used just single panes of glass, and glass is a very poor insulator.   If you’ve got an older home with single pane glass windows you know how cold that glass feels in the winter.  The double pane window was introduced in the early 1950s.  The air space between the two panes created an insulating space.  You can now order windows that are filled with gas such as argon, that is an even better insulator than ordinary air.  And there are some cases where triple pane windows might be a good idea, such as a north-facing exposure that gets strong winter winds or a southern exposure that gets direct summer sun for a good portion of the day.
  • Low-E glass coatings: Many replacement windows now have as either standard or an option a coating known as low-E.  This coating further reduces heat transfer by reflecting infrared rays.  This keeps your heat from leaking out in the winter and the outside hot air from making its way inside in the summer.  Low-E glass also cuts down infiltration of UV light rays that can fade or deteriorate your furnishings.
  • Warm edge spacers: As a part of the window manufacturing process, spacers are inserted around the edge of the window frame to insulate the edges and reduce heat transfer.

If you’re tired of your hard-earned money literally flying out your old windows, we’d be happy to answer your questions about how the windows we offer can cut your utility bills and improve the value of your home as well as its comfort.  We are THE replacement window company for the Minneapolis area, and we are a licensed Minnesota home remodeling contractor.




Window Outfitters is a premier Window Replacement, doors, siding contractor and installer. As Contractor in the St Paul, Minneapolis, (Twin Cities) Minnesota (MN) metro, we proudly serve, but are not limited to, the following areas: Minneapolis Energy Efficient Vinyl Windows, Replacement Window Contractors Minnesota, Burnsville, Apple Valley, Lakeville, Savage, Bloomington, Edina, Richfield, Eagan, St Paul, Hastings, Minnetonka, Plymouth, Maple Grove, Eden Prairie, Farmington MN, Chaska, Shakopee, Chanhassen, Victoria, Mendota Heights Anderson Windows Minneapolis, Marvin Windows Minneapolis.