When it comes to energy efficiency, windows play a very important role in reducing a home’s heating, cooling, and lighting costs.
A window’s energy efficiency is primarily measured by the U-factor, the rate that a window, door, or skylight conducts non-solar heat flow. The lower the U-factor, the more energy efficient your window!
Here are some common components that affect the energy efficiency of a window:
As the skeleton of your windows, the material of your window frames is key in determining their overall energy efficiency:
- Metal or Aluminum frames are inexpensive, light, and sturdy, but score lower on the insulation scale because they conduct heat fairly quickly.
- Wood frames insulate well, but contract and expand in response to weather changes, meaning they require regular maintenance.
- Vinyl frames have hollow cavities, which means that they can be filled with insulation, increasing their thermal power.
- Fiberglass frames also have hollow cavities that can be filled with insulation and are very low maintenance, making them an option that has been growing in popularity in the past years.
More is less when it comes to window panes! Multiple panes resist heat and insulate better than a single pane – the more panes your window has, the lower your energy bill!
Colours matter when it comes to glass – grey and bronze-tinted windows will reduce light and heat penetration, whereas blue and green-tinted windows allow light in but reduce heat transfer.
If you’re not a fan of colour, a more popular option is adding a low-emission coating to your windows. A low-e glass coating, which is a very thin metal layer applied to the panes of glass, lowers a window’s U-factor, minimizing your window’s solar gain and increasing its overall energy efficiency.
Even the invisible components of your window contribute to its overall energy efficiency! Some gases like krypton and argon, which are non-toxic, colourless, and odourless, insulate better than regular air – filling the space between windowpanes with these gases will increase your window’s overall insulation, giving its energy efficiency a boost.