Windows plays a massive role in determining the size of your energy bill. According to the United States Department of Energy, heat gain and heat loss from inefficient windows makes up for 25 to 30 percent of residential heating and cooling energy use.

That’s over a quarter of your energy bill.

That quarter of your bill that results from inefficient windows could easily be reduced by installing energy-efficient windows in your home. That’s why we’re providing you with a guide to energy-efficient windows that examines common frame types, glazing types, and other considerations that will help you make an education decision on what windows would be best for your home.


There are typically four types of frames when discussing energy-efficient windows: composite, fiberglass, vinyl, and wooden frames.

  • Wood is a fairly good insulator, but it requires regular maintenance that composite, vinyl, and fiberglass typically do not. Sometimes, wood frames are paired with metal, but this reduces their energy efficiency, as metal conducts heat quickly.
  • Composite frames are made from multiple types of wood and have the same, if not better, thermal properties than wood, with better resistance to moisture and decay. Composite frames to not require as much regular maintenance as wood.
  • Vinyl frames are made from polyvinyl chloride, commonly referred to as PVC. These frames often implement ultraviolet light stabilizers, which prevent damage from the sun. Vinyl frames are typically hollow, which allow them to be insulated. This gives them better thermal properties than standard wood and uninsulated frames, making them a very efficient option for your window replacement project.
  • Fiberglass window frames can also be filled with insulation, making them a superior option to wood and other uninsulated materials, like composite.

Each frame type has its benefits and drawbacks, but for maximum energy efficiency, it’s worth considering frame materials with hollow cavities that allow for further insulation, which will reduce the amount of heat that enters and exits your home.

Glazing Types

Another factor in choosing energy-efficient windows is the type of glazing you use. Glazing is simply the type of glass you choose for your window, but there are plenty of options to fit various levels of energy efficiency that you would like to pursue.

  • Low-emissivity glass refers to window panes that are coated with a special material that buffers the intensity of ultraviolet rays that comes from outside the the inside of your home. Low-E coatings improve the thermal efficiency of your windows, while also reducing the possibility of interior damage from UV rays. There are also more advanced versions of Low-E coated glass, which cut out 40 to 70 percent of heat transmitted, compared to the 30 to 50 percent that regular Low-E coatings prevent.
  • Insulated glass is a term that some say is a misnomer, but insulated glass refers to windows which feature two or more glass panes. Using multiple panes, contractors space the panes apart and seal them, creating a space between two panes that is “insulated” with air.

Gas Fills

Today, window technology has improved exponentially since the windows of yesteryear. An option to increase energy efficiency is to install gas-filled windows, which is when two panes have a gas like argon or krypton in between them. These gases — which are non-toxic and odorless — help to minimize the amount of heat the gets transferred from the inside and outside of the window.

Using dense gases to serve as an insulator helps keeps the inside of the home protected from differing temperatures than otherwise would come in through windows and increase heating and cooling costs.

If energy efficiency is your goal, windows are a great place to start. Window replacement will help address unnecessary energy costs by significantly cutting them. There are plenty of options when it comes to energy-efficient windows, so be sure to do research on what options are the best fit for your budget and your home.

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