We’d all like our homes to feel inviting, warm, and happy, and according to new research published in the journal Building and Environment, there’s one factor in your space that can seriously affect your mood: lighting. Here’s what the study found about how to use light to your advantage at home.

Studying the impact of light on mood.

In order to study the relationship between natural light and emotional well-being, researchers created 25 different simulations of homes, each filled with different amounts of natural light. Some houses, for example, were rendered to have more windows, while some had larger windows and others had windows facing different directions relative to the sun.

Then, 750 participants explored the simulation homes and rated how each one made them feel on a scale from 1 to 10.

The findings and how to apply them to your space.

Natural light was clearly the winner in terms of what kind of lighting made people the happiest—and the more light, the better. Homes with windows covering at least 40% of a room’s wall space were generally most favorable, and the strongest impact of lighting on mood was observed in women and participants under 30.

Additionally, the color and material of indoor walls made a difference in mood based on these findings. The study authors note that white and clearer tones affect the lighting of a space by reflecting (and subsequently “boosting”) light, while dark colors absorb it. Brick was the least happiness-inducing material, and the findings on wood were inconclusive since the material varies so much.

From an architectural perspective, as study co-author Pablo Navarrete-Hernandez, Ph.D., explains in a news release, “Our findings indicate that by maximizing window sizes, increasing the distance between dwellings to reduce shade, and using wall materials and colors that better reflect light, people perceive an increase in happiness and a decrease in sadness.”

And in terms of how to optimize the light in your own home, keeping your blinds open during the day and strategically placing mirrors to reflect window views can make a big difference. And according to this study, introducing lighter shades and finishings can also help ladder up to a sunny disposition at home.

Natural lighting plays an integral role in regulating our circadian rhythm, and this research suggests it can affect mood at home, as well. So consider this your sign to open up those window shades and let the light in.