Double Pane or Triple Pane Windows. Are They Worth the Investment?

photo of 3 replacement double pane windows

Are you thinking about replacement windows for your home? If so, you may have become familiar to different options including the number of panes, double or triple pane. But you may be wondering what the panes mean and if the extra cost is worth the investment. We’ll explain what double pane and triple pane windows are and how they offer added energy efficiency.

Understanding Basic Heat Gain and Heat Loss.

As a homeowner, you should understand the basic principles of heat gain and heat loss, or thermodynamics. After all, you may have decided to replace your windows to increase your home’s energy efficiency.

Heat gain is the total amount of heat transferred from outside to the inside of a building. Sources of heat gain include your heating system but also things like the sun’s heat and heat given off from appliances and even your body heat.  

Heat loss is the total amount of heat transferred from inside to the outside of a building. This can occur through conduction in the walls, floor, roof, windows and doors. As a homeowner, you should be concerned about both heat gain and heat loss.

As you are shopping for new windows, keep in mind that they should provide good protection against heat loss. The number of panes in a window will impact heat loss as will proper installation of any window. A good window installer will measure your home’s thermodynamics an install new windows that increase your home’s overall energy efficiency.

How Does Heat Loss Affect A Home?

Because your home remains roughly the same temperature throughout the year, its heat gains are equal to its heat losses. But if your home is inefficient, this balance gets out of whack. As your heat loss increases, you attempt to compensate. Your HVAC (heating and cooling systems) may become overburdened and your energy bills will rise.

This may happen over time and you may not realize that heat loss is affecting your home. There are numerous factors that impact your home’s heat loss, but no doubt your windows play a large part. The age, condition, and type of windows you have are major factors. If your windows are single pane, old, or leaking, new replacement windows will benefit your home.

How Do The Number of Panes of Glass Matter?

Simply put, the more panes of glass in a window, the less heat loss you will have. Just like thermal underwear’s small air pockets in the material that provide you warmth, the space in between the panes of glass provide an insulating factor. With the added layers of glass and the gas-filled space between lowers the heat condensation, or heat does not escape or enter the home as easily.

An additional benefit is the added panes will reduce sound. Just as the added panes of glass reduce transfer of heat, sound does not travel through as much. This can be an added benefit.

Replacement windows should help reduce heat loss.

Are Single Pane Windows Still Available?

Well, yes, you can still find single pane windows out there. In fact, many homes still have single pane windows. But it is not recommended because they are inefficient. Remember, single pane windows are made with a single layer of glass. As you can imagine, they are not as heat efficient. Double pane replacement windows perform exceedingly better than single panes of glass.

What is a Double Pane Window?

Double pane replacement windows have two sheets of glass, known as panes and a spacer in between. Double pane windows are great at reducing heat loss. They are generally less expensive than triple pane replacement windows.

Double pane windows are available in a variety of frame choices. Vinyl or fiberglass frames are generally the best options. These frame types are designed to support the double pane glass. They don’t warp or bend as much as wood might. Both vinyl and fiberglass also add to a higher level of energy efficiency, with fiberglass being the most efficient.

It is good to know how a window is built. Sometimes, double pane windows can have a gas fill between the panes of glass in order to add thermal efficiency. Argon and krypton gases are commonly used. There are other window film options that you can opt for that may increase efficiency.

What is a Triple Pane Window?

Certainly an upgrade from a double pane, a triple pane replacement windows offer three panes of glass and two spacers. As you can imagine, they are much heavier than double pane windows and more efficient. There is a significant difference in performance between double pane replacement windows and triple pane replacement windows.

As with double pane, the framing choice comes into play. Because there is more glass, vinyl and fiberglass framing make good options to reduce bending and warping. And you can opt for gas-filled panes or window coatings to help decrease heat loss.

How is Energy Efficiency Measured in Windows?

Window Energy Efficiency is assessed by measuring the heat they let in or out. This is called their U-valueIf the U-value is high, the window can let more heat through; if it’s low, then it means the window is more efficient and less heat gets through it.

Double pane windows may have a U-value of .30, compared to a single-pane window with a U-value around 1. Triple pane windows are the most efficient with U-values as low as 0.15. The lower the value, the more efficient.

What Is the Cost Difference Between Double and Triple Pane Windows?

Because there are so many options out there when it comes to windows, it makes it difficult to compare only the number of panes as a cost differentiator. You can expect that double pane is more expensive than single pane (about twice as much). Likewise, triple pane windows are more expensive than double pane (about 30% more). Best way to approach it is to educate various brands and window features.

In conclusion, whichever you choose, double or triple pane windows you’ll be making a wise choice for your home. When evaluating windows, consider the number of panes, framing material, U-value, functionality and aesthetics. It is wise to get an energy efficiency evaluation done as well as several professional quotes for window replacement.