Anatomy of a Window

By August 12, 2011 Understanding your home, Windows

Estimated reading time: 3 minutes, 5 seconds

Anatomy of a window

Windows come in all shapes and sizes. They essentially let light in and have glass in them, which allows us to see out, ideally without losing heat. Many of the windows I come across are ruined by settling and/or too many poor paint jobs, you name it. Imagination is the only limiting factor. Prices range from $80 to $2,000, depending upon how specialized they are. Some shops charge for custom sizes, some do not. Like Pizzas, all windows are not alike. In most cases price denotes value. That being said, it is often too hard to tell the difference and some familiar name brands just cost more. Much of the decision is based upon the supplier and the service they provide.

This represents a double hung window and its components. These terms are the common ones used to describe the parts, however, some in the industry have slightly different names for them. Getting clarity before ordering is always a good idea. Interestingly muntins is spelled “Rong” in the diagram. That parting strip is commonly called the parting bead.

For the North End of Boise Idaho that I remodel in, we have the historic review and there are strict guidelines for “contributing homes” A newly approved window is made from fiberglass. Vinyl windows on the front of the home are prohibited. Wood and metal clad wood windows are approved if the muntins are of a historical pattern.

Types of windows

This is a great image in that it illustrates just how many types of windows there are. It is in no way a complete list. Some windows lend themselves to be cleaned from the inside by tilting in, which is a cool feature. There are even retrofit windows called sash packs. They only replace the guts of the old double hung wood window. This upgrades the functionality without disturbing the exterior trim of the home.

How do you describe the size of a window?

A window is always described by its actual size not to be confused with the required rough opening. It is also described width first. A 3026 is a 3 foot wide window by 2 foot 6 inches tall.


Next to having your attic insulated your windows are the biggest offender of energy loss. There are many inert gasses like Argon and multiple panes of glass then there are multiple films that can be added to improve the ability for solar energy to be reflected.


Installing windows properly is a must. Without enough insulation during the install you could lose the gain you bought with expensive windows. What constitutes “proper installation” is a big deal. Since we live in a fairly dry climate proper moisture protection is not as big a deal. In other words, someone in a rush might cut corners and not use an upper drip edge or Vicor to properly wrap the window. At Levco we follow the manufacturer’s recommendations for new installations and retrofit installation as if we lived in Portland Oregon. ( Sorry Portlanders, but you rust rather than tan in the summer)

What you see is what you get:

My favorite window showroom experience was at Truitt & White Lumber company in Berkeley California. They had an example of each of their windows in a larger window so you could look through and compare exactly what each film and glass treatment does to the view. It is amazing what you can tell when you have them all in a row.

No matter what windows you choose or who you choose to install them do your homework to insure your hard earned money is used wisely.

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