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Serving Homeowners in the Treasure Valley and Eastern Oregon

Energy Efficiency In Insulated Windows

large multi-paneled insulated windows

In the winter, heat loss can be a huge issue, and summer temperatures aren’t kind to AC units. When you live in an area with as much volatile weather as Treasure Valley in Idaho, it only makes sense to have insulated windows you can count on to be energy efficient – both to save energy and to keep you at a comfortable temperature.

Types of Windows

Some windows naturally have better energy efficiency than others. Because of the way they are constructed, they keep heat transfer from becoming an issue. Each has its own way of doing this, and some styles are better for certain areas than others.


A double or single-hung window opens vertically. On a double-hung window, both the top and bottom sections slide up or down to open the window. In the summer, having a way to vent the heat that rises to your ceiling can be best treated with the top open on a double-hung window.

A single hung window only opens in the bottom half. It has a division across the center, but the top is fixed in place. Having this additional seal makes sure that air can’t leak through the top and sides of the higher section if it is installed properly.

Slider windows open opposite by opening horizontally. In some styles, both sides are movable, but most often one is fixed in place. These are great for getting air into your house without having a divider in the middle of the airflow. They are also usually the easiest to fit an AC unit in, but they will require a covering for the rest of the open area.


Casement windows open out from the house to catch air and direct it into the building. They attach on hinges either on the left or right side. Because wind can be a concern for these windows, they have a much sturdier seal, but they aren’t the most practical window for Idaho.

A type called Awning windows is similar, but it connects at the top instead. This is especially good for allowing heat flow in rainy areas. Since this window also opens outward, it has a natural cover against precipitation getting in while allowing air in.


Fixed windows don’t open at all. Picture windows, glass block windows, and most skylights are all types of fixed windows. With fixed windows, you don’t have to worry about the outside air reaching inside your windows unless they aren’t installed properly or have experienced thermal expansion over time.

Fixed windows do a great job of allowing sunlight in while keeping the air and even outside noise out. But if they don’t have good insulation, the natural light can cause a higher solar heat gain coefficient (SHGC), meaning your house will heat up outside of your control and without ventilation.

Types of Insulation

Some types of windows allow for internal modifications, but all types can have benefited from external methods. Insulated windows will increase your home’s energy efficiency and allow you to have more control over the temperature, and even safety rating, of your home.


One solution, and definitely one of the easiest ways to reduce heat transfer through your window, is to simply cover it during times when it will cause the most transfer. On hot or cold days when you aren’t home, you can keep the blinds or curtains closed.

Having blackout curtains in the summer, for example, is great at blocking the sunlight that heats up your house as well as containing the heat that does get through. In the winter, blackout curtains or tapestry curtains contain the cold in the same way overnight in cold climates.

Surprisingly, a thin layer of air between the window and the next barrier is extremely effective at reducing energy transfer between two areas, even including noise pollution. The efficiency increases with the thickness of the barriers.


This air barrier can be created without covering up the window and blocking out light. Insulated glass windows can be manufactured with space between layers of glass filled with non-toxic argon or krypton gas, depending on the thickness, to reduce conductivity. Energy-efficient windows can have two or three panes separated this way.

Some double-pane or triple-pane windows have blinds or curtains inside the space between panes. When gas fills up space between the extra layers, window condensation that would otherwise cause damage to a wooden frame or wall around the window can also be reduced. This prevents cracks or holes in the seal around the window frame which would have to be refilled with caulking or weather strips to cover the leaks.

Secondary Glazing

On single-pane windows that don’t have the same doubled-up barrier, there are a variety of coverings that can go on the window itself to improve energy efficiency. Window insulation film can simply be shrink-wrapped to the surface of the window’s inner frame using a hairdryer, but if done improperly can be unsightly.

Secondary glazing can also be added as a temporary or permanent solution. This is adding an additional pane of glass to create post-installation double-pane windows. Checking the thickness of your window and the add-on, as well as how much space you want between panes, is an important consideration.

Low-E coatings (low emissivity coatings) will reflect infrared light and only a little visible light to reduce the amount of heat without reducing the amount of light coming through a window. These window treatments can be especially effective indoors, including sliding doors, that won’t be covered.


If all else fails, or if your windows are too old or outdated to be effectively worked on, it is time to consider new construction. Adding new, high-performance windows to your home can improve your energy use and make a huge difference, especially in colder climates. These insulated glass units will make it more difficult for breaks and cracks to happen, will keep out the weather, and will give you an opportunity for light and airflow your way.

HBSI uses ProVia windows that can be built according to your specifications in a variety of types. Even the frame material and latches can be customized. Whether you want to preserve your existing windows with the help of a professional or completely update them with replacement windows, HBSI professionals can help with a proper installation and an energy star label you can count on.