WorkAboutApproachInsightContactDC · MD · VA
A light-filled attic space in Petworth, DC
The Lived-In House  ·  Daylight

The Case for One More Window

Daylight is the cheapest luxury in a house, and the research says it makes the people inside measurably better.

The Lived-In House
Interior daylight
Daylight at work

A window is the cheapest luxury in a house and the one people underrate most. We tend to argue about finishes and fixtures, the things that photograph well, and treat daylight as whatever happens to come through the openings we already have. But light is the material a room is actually made of. Change the light and you change how the space feels at every hour of the day.

The case is not only aesthetic. It is measurable. Research from Cornell University found that people working beside well-placed daylight reported an 84 percent drop in eyestrain, headaches, and blurred vision. A separate sleep study found that those with daytime light exposure averaged roughly 46 more minutes of sleep a night. A room is not just brighter with the right window. The people in it are measurably better.

01
Orientation

It is not more light. It is the right light.

South light is generous but needs managing, with an overhang or a deeper reveal, or it overheats the room by afternoon. North light is the quiet gift: steady, soft, and never harsh, which is why artists have always wanted it. East light wakes a kitchen. West light warms a room at dinner and can blind it at the wrong moment. The skill is not adding glass. It is putting the right opening on the right wall for the way the room is used.

From the field

I once added a single high window on the north wall of a kitchen that already had plenty of glass to the south. The owners told me later it was the change they noticed every morning. The south windows gave them sun. The north window gave them a light that never glared, and it turned a bright room into a calm one.

Light is the material a room is actually made of.
02
The transom

Small moves, large effects

You do not always need a wall of glass. A transom above a door carries light deeper into a plan. A window turned into a corner dissolves the boundary between inside and out. A clerestory set high on a wall washes a ceiling and makes a low room feel taller. These are modest, affordable moves, and they change a room more than another few feet of countertop ever will.

Hidden Treasures, Petworth
Hidden Treasures  ·  Attic and roof deck · Petworth, DC
03
Living value

The return you actually keep

There is a resale argument here, but it is the smaller one. The 2025 Cost vs. Value report is a useful reminder that the truest measure of a change is not a percentage at sale. It is how much better the house serves the people in it every day they live there. A well-lit room pays that return each morning, long before anyone thinks about selling.

So when we plan a kitchen or a primary suite, the first conversation is rarely about cabinets. It is about where the sun comes from, and how to let the room have it.

Urban Oasis
Urban Oasis  ·  Near-complete rebuild · Kent, DC
Let the light in

Imagine your rooms with the right light

Get your free first concept image and see what one well-placed opening could do for the room you use most.

Get your free concept
Free first concept image - no obligation
Notes & references
A. Hedge, Cornell University, Daylight and Workplace Study (daylight and eyestrain, headache, alertness). Boubekri et al., Journal of Clinical Sleep Medicine (2014), on daylight and sleep duration. J. Pallasmaa, The Eyes of the Skin. Zonda / JLC 2025 Cost vs. Value Report. Project imagery: Hidden Treasures (Petworth, DC), Timeless Transformation, Luis Boza Architect.
← All of Insight