One person, a bad apartment, and too much free math

Why this exists

I'm Jenny Aquaro. I live in the Raleigh, NC area, and before I built things for a living, I ran marketing and brand strategy for other people's companies — agency work, over a thousand social media clients passing through at various points. I left that in October 2025 to build my own products instead.

Sunlight makes me happy. That's not a metaphor — I mean it in the literal, physical way. My last apartment was beautiful. I loved almost everything about it. It also got no direct sunlight, and I didn't fully understand what that meant until I'd lived there a while. I tried to keep a garden going on the balcony and it never had a chance. The place just wasn't built to catch the sun, and nothing about the listing had told me that.

So this time around, when I started looking again, light wasn't a nice-to-have on my list — it was the thing I was actually optimizing for. And I ran into the same problem everyone runs into: there's no good way to check it ahead of time. Listing photos are shot at golden hour with every lamp on. Sun apps show you a compass and leave you to do the math yourself. Agents shrug, because it's genuinely not their job to know. But the direction a building faces plus where the sun sits at any given hour is just physics — public data, free to pull, straightforward to calculate. Nobody was putting that in front of people before they signed a lease or a mortgage. So I built it.

How it actually works

No proprietary black box here. The short version:

• Address in, coordinates out. Geocoding runs through OpenStreetMap's Nominatim, which is free and doesn't require an account.
• Building orientation. The tool pulls the building's footprint from OpenStreetMap via the Overpass API and figures out which way the front of the structure actually faces. When the map data is thin — which happens, especially in newer or rural areas — it falls back to road geometry and says so, rather than guessing silently.
• Sun position math. Standard solar position equations (azimuth and altitude by time of day and time of year) run against your building's orientation to figure out when and where direct light hits.
• The result. A grade and a plain-English breakdown of what the light actually looks like, hour by hour, season by season — not just a number.

Everything runs in your browser. No account, no app to download, no sign-up wall between you and the answer.

What this is and isn't

This is a free tool, not a real estate brokerage, not a listing site, and not affiliated with Zillow, Redfin, or any agent network. If you paste in a Zillow or Redfin link, the tool is just reading the address off the page to run its own independent calculation — it isn't pulling anything proprietary from those sites.

It's also not a substitute for actually visiting a home. Trees grow, neighbors build additions, and map data has gaps. Treat the grade as a strong starting point for what to expect, then verify with your own eyes when you tour.

What's next

The web tool is free and stays free. There's a Chrome extension that overlays sunlight grades directly on Zillow and Redfin search results, and a small set of tools for agents who want to include a sunlight read in their listings. Both came out of the same instinct as the original tool: people shouldn't have to guess about something this checkable.

Questions, bug reports, or a building your area that the map data got wrong? Use the contact link in the footer. I read all of it.