All About Windows: A Client's Guide to Selecting the Right Windows

The windows on your home come in just about every shape and size (literally) imaginable. From large, fixed window units for letting in lots of light, to small windows over toilets, or even tilt-turn windows made to optimize airflow.

In this article, we'll talk all about windows, breaking them down by their jamb material, swing and operation, number of panes, and solar heat gain coefficient. We'll provide examples of each that we've personally installed, along with their pros and cons. Let's dive in!

Floor-to-ceiling tilt and turn windows being installed at the Stewart Trail Passive House.

Which Window is the Right Window?

The right window is the best window that your budget will allow for. There's a lot of things we're unwilling to compromise on when building a home, and windows are at the top of that list. Not only is a cheap, builder-grade window not that fun to look at (or through), a cheap window is incredibly inefficient from an energy efficiency point of view.

At a minimum, were installing a fiberglass jamb, double-paned window on any home we build. And even at that level, we're making compromises in quality and efficiency.

My philiosophy is to spend the money up front on the parts of your home that are not easily replaced. Trim, doors, fixtures and appliances are all budget items that can be easily upgraded in the future. Upgrading your windows, however, involves removing siding, removing the window units themselves (often times from the safety of scaffolding or by using large equipment), or even altering the structural framing. This is why it's important that we invest in a quality product up front.

Window Construction and How to Spot a Quality Product

So how do we sift through the dozens of window companies to find a quality product? Within the residential window world, you've probably heard of Andersen, Pella, Marvin or Milgard. Each of these companies has multiple product lines, each with different features. For a standard, fiberglass, double-pane window, you really won't go wrong with any of the companies I've listed above.

But that's not why we're here. We want to understand what makes a $1500 window better than a $500 window. So lets start with the glass itself.

Window Glass

The two major differences you'll see with the types of glass used in building windows are laminated glass and tempered glass.

Remember in Home Alone when Harry and Mar are breaking into Kevin's home? Harry wraps his hand in a cloth rag, shatters the window, and carefully reached inside to unlock the door. That's plate glass, and is no longer used in window construction because of safety issues.

Now we use laminated glass that will "spider-web" instead of breaking into shards. Laminated glass is the most common glass you'll find in a standard, new-construction window. It's made by sandwiching a layer of transparent vinyl between two thin panes of normal glass.

Tempered glass (also known as safety glass) is the other type you'll find in a new-construction window. It's roughly four times stronger than laminated glass and is used in glass exterior doors, windows that are lower than 18" off the floor, shower doors, or skylights. They are treated with high heat, and if they do break, break into dull pieces that won't cut when you pick them up.

Because of the higher cost of a tempered glass unit, they're only used where they're needed. But this is an important consideration, especially if the home design incorporates floor-to-ceiling windows.

Window Coatings

The most common glass coating you'll see us use is a Low-Emittance glass coating. A Low-E coating is a layer of glazing (usually some sort of metal oxide) on the exterior of the window or door that reduces heat transfer (expressed as a Solar Heat Gain Coefficient in the form of a decimal) from the exterior to the interior by 30%. See this article for the full breakdown.

What a Low-E coating is doing is reflecting the heat from the sun away from the window surface. In a standard window, the glass absorbs that heat and transfers it to the interior. That's why you sometimes get the greenhouse effect with south-facing windows without this coating.

Jamb Material

Now that we've gone through the types of glass and coatings, lets dive into the part of the windows that keeps the glass in place: the jamb.

In window construction, you'll find that the jambs come in three main material types: wood, fiberglass and aluminum. Many window companies also combine two of the tree main types for a hybrid window jamb. The most common hybrids are aluminum-clad wood and aluminum-clad fiberglass.

For the purpose of this article, we'll stick to the main three types: wood, fiberglass and aluminum.

Wood

Wood jambs on windows are beautiful. There's a natural warmth and beauty to wood that no other material can replicate. But wood is not a very good insulator. The properties of wood don't allow it to retain heat or repel cold to any meaningful degree. It's why we go back and insulate our wood homes with a material that is good at retaining heat and repelling cold.

Wood is also heavy compared to the other two types. Wood is also prone to warping. However, to get around this, companies will use hardwoods such as maple or poplar, finger-jointed together to achieve a jamb that is sturdy and won't warp as badly.

Wood is also quite a bit more expensive when compared to fiberglass or aluminum. This difference can be ~20% - 25% higher of the same size and type of window in fiberglass.

Fiberglass

The fiberglass in window construction is not the same as what you'd find in the walls of your home. It's mixed with plastic and extruded into whatever shape is needed.

Fiberglass is the most cost-effective jamb material of the three. It's also has the highest insulation value. It's also the lightest material used in window construction.

The aspect of fiberglass jambs that I like the most, however, is that fiberglass doesn't expand and shrink like wood and aluminum, meaning it's the most stable material. It expands and contracts roughly the same amount as glass does, meaning you won't get gaskets and seals working loose over time.

This is important to consider, because the window jamb will be subject to daily cycles of heat and cold (especially in Star Valley, Wyoming, where we can have 40-50 degree temperature swings during the summer months!).

This is the only window jamb material you will see us use when building passive or high performance homes.

Aluminum

Aluminum sits slightly above wood when it comes to performance and efficiency. It mimics a lot of the qualities of wood. The decision to use aluminum clad windows usually comes down to aesthetics and design.

Window Swing and Operation

Below, I've included a infographic that breaks down the most common types of windows you'll see:

The most common types of windows you'll see in residential custom home building in Star Valley, Wyoming.

Another type of window that we install regularly are tilt-turn windows. Using the picture above, they are a combination of a casement window and hopper window. By turning the handle 90 degrees, you enter the "casement" mode. Closing the window and continuing to turn it another 90 degrees in the same direction puts the window into "hopper" mode.

I generally shy away from using double hung or slider windows, the main reason being the seals on those windows fail much quicker than the seals and gaskets on casement windows.

Double-Pane vs. Triple-Pane Windows

Roughly 70% of the windows we install in homes are double-pane windows, meaning there are two separate panes of glass with an inert gas (usually argon) that fills the void between the panes.

In Star Valley, Wyoming, this is the most common type of window you'll see and is the standard for our climate zone.

More and more we are installing triple-pane windows - same construction as double-pane, the manufacturer is simply adding another layer of glass to the window unit. This has a few key benefits.

First, three panes of glass further increases the amount of heat transfer from the exterior to the interior. By adding a Low-E coating, we can bring the amount of heat that is radiated away from the interior to 70%. This is how we avoid large temperature swings inside the home, increasing your comfort.

Second, the sound dampening is unrivaled. Remember the scene in Ace Ventura: Pet Detective where Ace proves the point that Roger Pedactor couldn't have been heard from outside on the balcony? Three-panes of separated glass can block out the noisiest highways sounds for better quality of life.

Third, triple-pane window units have to be thicker to accomodate the extra panes. This means your jambs are thicker, which means we can over insulate the window jamb itself. Triple-pane windows offer the highest insulation values of any windows on the market.

So Which Window is Right for You?

As I mentioned earlier, your budget will ultimately reflect the options we choose for your windows. Many times, clients make the choice to prioritize interior comfort over higher-end finishes, in which case we go for a more expensive (but ultimately more cost effective) triple-pane window unit.

But there is NOTHING wrong with a double-pane unit. It's most of what we install in custom homes in Star Valley, Wyoming. It all comes down to having those conversations about what you value.

If you're curious about how the process works when you work with Unshakeable Custom Homes, reach out. Whether you just want to talk about windows, discuss design or floorplans, or understand our process more, I'm always available to chat.