How to Determine the Ideal Window Size for Your Home

How to Determine the Ideal Window Size for Your Home

By Alex Mikayelyan June 20, 2024

Natural light plays a huge role in the atmosphere and vibe of your interior. This is why professional interior designers put so much emphasis on controlling the amount of natural light within the interior. The biggest source of natural light in your home is the windows. Several factors contribute to the amount of sunlight that your windows allow into your home.

The layout of the interior is one, as is the direction that your home’s facade faces. But among these determinants, the size of your windows plays a huge role in how much natural light makes its way inside. Some mistakenly believe, that since bigger windows let in more natural light, by default they are better than smaller ones, right?

Well, the answer is not that simple and there are a few more nuances to consider before deciding on the size of your windows. Even if window sizes may seem like a relatively small detail to consider when designing the exterior of your home, they can have quite a large impact on the interior overall.

Things to Consider Before Window Installation 

While there isn’t necessarily a normal window size that fits all houses across the country, there are certain personal preferences and local regulations you should consider before deciding on the window opening size.

The Interior

How Window Sizes Depend On the Interior

How Window Sizes Depend On the Interior

First, you need to understand the functionality of your room and how you want it to look. The living room, for example, generally requires plenty of sunlight as this is a room that is commonly used all throughout the day, from morning to night. A bedroom, on the other hand, may not need as much natural light, as for most people the bedroom is reserved for sleeping at night and too much access to the exterior may not be as beneficial.

The Exterior

How Window Sizes Dictate What Is Visible from the Outside

How Window Sizes Dictate What Is Visible from the Outside

Another important factor to consider when deciding on window sizes is the exterior of that room and what you want to be seen from the outside. Bathroom windows, for example, are mostly used to improve ventilation and give steam a more effective way of escaping the stuffy room.

These windows are rarely installed to give a gorgeous vista to look at as they are taking care of personal matters. On the other hand, there are some rooms where exposure to the outdoors is not as big of a deal as with bathrooms or bedrooms. So, homeowners don’t mind sacrificing a bit of their privacy in hopes of increasing the amount of natural light that comes through. 

Building Codes

Why Window Building Codes Are In Place

Why Window Building Codes Are In Place

Then there are building codes that dictate the number and size of windows you can have in your home’s exterior. Building codes exist as a way to ensure that you do not weaken the structural integrity of your home. You may not consider this at first, but having windows built into load-bearing walls does weaken them to some extent.

So having a ton of big windows on such a  wall could be a potential risk. With the building codes in place, contractors know exactly how many windows should be installed, as well as how big they should be, in any particular wall. 

Window Frame Measurements

Here are some of the measurements you should consider when looking to install custom-size windows. Keep in mind, that while there is some amount of freedom you have to experiment with, there are certain determining factors, such as building codes, that can impose some limitations. It is a good idea to understand these limitations before choosing the size of your windows.

Height & Width

What to Consider When Picking the Height and Width of Your Windows

What to Consider When Picking the Height and Width of Your Windows

There is no such thing as  “normal window width and height”, as the designs of your windows are subjective. The dimensions depend entirely on the aesthetic of your home, its architectural design, and your preferences from room to room. According to Egress size regulations, however, the minimum size of windows should be 20 by 41 inches for small fixed windows.

Double-hung typical window width should be 34 by 42 inches, with each panel being 21 inches tall. But again, these window frame sizes are entirely up to you and the design of your home as long as local building codes are being followed. The window frame width and height also depend on how the room is being used. Living rooms, for example, can make good use of the natural light which you can get from continuous horizontal windows.

In bathrooms, a bay window is also quite common, as the side-by-side frames provide plenty of natural light, but because of their standard size, you don’t sacrifice much privacy. As for the kitchen windows, the natural light needs to hit specific points in the room. For example, you want natural light to brighten up the dining area as well as the countertops. In this case, the placement of your windows would be more important than the size itself.


The Importance of the Window Sill Height

The Importance of the Window Sill Height

The height of the windowsill essentially determines how high you want the window in your room to be. As with the other stylistic and practical aspects of your interior, the sill is determined by how you plan on using the room and how you want it to look, both from the inside and the outside.

Traditional window styles dictate that the window sill should be three feet above the floor. This makes them the perfect height not only for some added privacy from the outside world but also makes it possible for bigger sills to be used as shelving or seating. More unconventional house windows may have a completely different kind of window sill than this traditional design.

For example, many contemporary homes have panoramic windows, that make use of max window sizes to allow for as much natural light as possible. The key to panoramic windows is to forgo the sills or have very thin window frames. This means you minimize privacy but maximize the natural light and the view of the surrounding landscape. Thus, panoramic windows are best for walls looking towards open nature or a coast. 


How Window Headroom Is Determined and Why It’s Important

How Window Headroom Is Determined and Why It’s Important

Calculating the headroom is an important part of measuring windows for installation. The headroom, much like the windowsill, dictates how much natural light will get into the room, how much privacy you have in that room, and overall the vibe and atmosphere of the interior.

Again, as with the sill, the less headroom you have above the window, the more natural light will fill the room. Unfortunately, this comes at the cost of privacy and in some cases insulation. Panoramic windows can be gorgeous additions to any modern home, but unfortunately, glass is not as good of an insulated as thick exterior walls.

So for panoramic or bay window sizes, double glazing is certainly a must in order to properly insulate the room. Another important determinant of the window headroom is the interior door height. Oftentimes, the headroom above is equal to that of the headroom above the interior doors, which is a great way to keep the measurements consistent.


Written by
Alex Mikayelyan

Written by Alex Mikayelyan