Things to Consider When Choosing a Window Size

There are many window types on the market, and each has an ideal size for every house. Window size affects several aspects of your home, such as its aesthetics, energy efficiency and indoor comfort.  

Things to Consider When Choosing a Window Size

To get the ideal size for your preferred window, it’s best to know the following basic information.

Factors to Keep in Mind


Even if you can afford and fit a large window in a room, you shouldn’t do so until you’ve considered all the variables. Floor area and thermal mass are some of the most important considerations you should think about before choosing a size for a certain window.


  • Floor Area. As a general rule, the total glass area of a window should not exceed 30% of the floor space. However, the size of your east- and south-facing windows shouldn’t be more than 15% of the room’s total floor area. Depending on the floor material and the amount of sunlight that shines on the area, the size of north-facing windows can range from 15% to 25% of the total floor surface of the room. Finally, west-facing windows should be no larger than 10% of the total floor space of the room.


  • Thermal Mass. This refers to a material’s ability to absorb heat energy. The higher a material’s thermal mass, the more it absorbs heat energy and the longer it retains it. Thermal mass is directly related to the density of a material, so heavier materials such as concrete and brick have a higher thermal mass. Depending on what material is used in the construction of your home, you should adjust the size and orientation of your windows.  

Standard Window Sizes


Different types of windows have their own standard sizes to make them easier to design and install. So if you’re choosing specialized windows or getting normal window types with nonstandard sizes, you’ll have to carefully consider your budget and hire skilled contractors to do it for you. As a guide, here are some standard sizes for the most common window types:

Double-Hung Windows

  • Standard Width: 24 to 48 inches 

  • Standard Height: 36 to 72 inches 

Casement Windows

  • Standard Width: 14 to 35.5 inches 

  • Standard Height: 29.5 to 77.5 inches 

Sliding Windows

  • Standard Width: 36 to 84 inches 

  • Standard Height: 24 to 60 inches 

Bay Windows

  • Standard Width: 42 to 126 inches 

  • Standard Height: 36 to 78 inches 


Renewal by Andersen of Sacramento is a reputable window contractor that can provide you with all your window needs. From quality products to top-notch services, we are the industry professionals you can depend on. Fill out our contact form or call us at (916) 779-5800 to request a quote.