What are the Best Windows for Cold Climates

The northern regions of the US experience brutally cold weather. Freezing temperatures persist for months, and it isn’t unusual to see them dip below 0 degrees.

What are the best windows for cold climates?

Let’s first start by showing which areas of the country fit this description.

Windows for cold climates are essential in Zones 1 through 5 of this map.

Note the “Average Minimum Temperature” in these regions. Another way of saying this is “the lowest temperature typically experienced in a year.”

It ranges from below -50F to -10F through -20F.

That is some very cold weather!

Other Zones? If you live in Zones 6 through 9, your lowest winter temperatures are typically below freezing. You might want to consider the best windows for cold climates too.

The Best Windows for a Cold Climate: An Overview

There are two window components to consider: Window frames and window glass (also called glazing).

Window Frames: The best frames for cold zones are:

  • Wood and Wood-clad frames
  • Vinyl frames
  • Fiberglass frames
  • Composite frames

Window glass: The best glazing packages include double-pane or triple-pane glass that is coated to prevent the transfer of heat from inside to the outside of the window.

Now we’ll discuss the frames and window glass separately.

The Best Window Frames for Cold Climates

Essentially, the best frames for cold weather are “anything but aluminum.”

Aluminum allows the rapid transfer of heat. In winter, heat in your home will steadily be lost through aluminum frames, and that will put your heating system into high gear. The result will be very high heating costs.

Our recommendations in order for window frames in cold climates are:

  1. Wood window frames with cladding: Wood is the best insulator, but harsh winters quickly take a toll of bare wood. That’s why wood windows with vinyl or aluminum exterior cladding make the most sense. You get the insulation value of wood, and the cladding protects the frames from harsh weather.

All the leading window brands make wood windows with exterior cladding, so you have a wide range of style and price options.

  1. Wood window frames with Fibrex exteriors: Fibrex is a proprietary product made by Andersen Windows. It is a blend of 40% wood fiber/sawdust from recycled materials and 60% thermoplastic polymer.

The window has the insulative value of wood and the weather-resistance of Fibrex. This combination is available on the Andersen A Series, one of Andersen’s top lines. We’ve completed a Fibrex Windows Guide with full details.

  1. (Tie) Vinyl window frames: Most are insulated to help keep heat in your home. Additionally, vinyl handles the elements such as snow, ice and freezing rain. The vinyl isn’t susceptible to warping or cracking as temperatures fluctuate between freezing and warm.
  2. (Tie) Fiberglass window frames: They share all the good qualities of vinyl window frames, but cost a little more to quite a lot more depending on the specific window brand and series.

Apart from cost, the performance of fiberglass is about the same as quality vinyl and better than cheap vinyl windows.

The Worst: Besides aluminum, non-clad wood windows are a bad choice for harsh winter climates. With them, you are faced with high maintenance costs or the hassle of painting them yourself every few years. The alternative is frames that will likely be damaged and possibly rotting within a decade.

The Best Window Glass for Cold Climates

The glazing you choose for a cold climate is just as important as the frame material.

There are several critical factors to consider:

  • How many panes
  • What’s between the panes
  • Glass coating

The Number of Windowpanes

First, nobody in any climate should choose single-pane windows. They are inefficient, to say the least.

In cold climates, you should consider double-pane and triple-pane windows.

R-Value measures resistance (R) to heat transfer. The higher the R-value, the more efficient the window.

Notice how R-value improves with more panes and with a wider air gap between the panes.

Panes & Gap R-Value
Single 0.91
Double w/ 1/4″ Gap 1.69
Double w/ 1/2″ Gap 2.04
Double w/ 3/4″ Gap 2.34
Triple w/ 1/4″ Gap 2.56
Triple w/ 1/2″ Gap 3.23

Data supplied by ArchToolBox

What’s Between the Panes

First we see from the table above that an air gap increases R-value, and the wider the gap, the more efficient the window. The air gap is a buffer of warmer air that keeps out the cold.

Gases are also used to improve R-value, and argon is the most common. For example, Pella makes a glass package called NaturalSun Low-E Insulating Glass with Argon.

It is an Energy Star certified glazing package ideal for the Northern US and Canada.

There is additional information in our Pella Window Guide.

What’s On the Glass /Low-E Glass

The glass can be coated on one or both sides to reflect heat. The coating is usually a blend of metallic oxide.

The coatings produce Low-E glass. The “E” in Low-E stands for emissivity, a measure of heat reflection.

Low-E coating on the inside of the glass keep heat in your home. Low-each coating on the outside helps keep out harsh summer heat. But in a cold climate, you’d welcome that heat into your home. The Pella glazing mentioned above isn’t coated on the outside, so it “allows the sun’s heat to flow in and warm your home.”

Talk with your window installer about glass options. The one you choose will make a difference in how comfortable your home is in winter and how low you can keep your heating bills.

 Comparing Windows for Cold Climates

All windows have an Energy Performance Ratings label like the Andersen Window label shown here.

They show three important ratings:

U-Factor: This number represents the total efficiency of the frame and glass combined. The higher the number, the more efficient the window.

SHGC: Solar Heat Gain Coefficient – This represents how much heat can pass through the window. Higher numbers mean more heat. However, for most windows, the SHGC is tied to the U-Factor, so if the U-Factor is good, then the SGHC will be low.

VT: Visible Transmittance is the amount of light (regardless of heat) that passes through the window. A higher VT means more natural light and less artificial light. Natural light helps reduce energy use in all climates, especially in cold/dark northern ones.

Talk to a Pro

Windows for cold climates should combine energy efficiency with tough materials.

There are a lot of very good options in Zones 1-5 and beyond.

The windows are important, but so is the installer. Make sure to choose a company with a proven track record of quality installation.

That’s why we recommend:

  1. Getting estimates from multiple contractors
  2. Comparing the Energy Performance Ratings for each product offered
  3. Checking Google and other rating/review sites to learn about the contractors

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