ohoya 🇩🇪 DE Reserve now
☰

Sun Check

How much sun does your room get - and how much would be possible?

Three inputs are enough. The calculation runs entirely in your browser: your location is neither transmitted nor stored.

1 · Where

North positive, south negative.

2 · Which way does the window face

The direction you face when you look out of the window.

3 · What is in front of it
12°

Determines how often the device itself sees the sun.

Result · annual average

- hours per day in which sunlight can be redirected to you

Directly at the window

- h/day

With a heliostat

- h/day

In December

- h/day

Days without any sun

- → -

Hours of sun per day over the year

Directly through the window Additional, redirected

What the calculation can do - and what it can't

  • Clear sky. It calculates the position of the sun, not the weather. Cloudy hours are counted too.
  • One surrounding height for all directions. A single tree due south or a gap to the west is not modelled.
  • A heliostat redirects sunlight; it does not create more of it. The result is a bright, moving patch of light - not an even illumination of the whole room, and no focal point.
  • Not every hour is worth the same. When the sun is at an angle to the path device → window, the mirror only presents part of its surface to it. Early-morning and evening hours therefore bring less than midday hours - here they still count as full hours.
  • The number of hours says "when it would be possible", not "how bright it gets". It counts the hours in which the sun is within reach of your device and your window does not already get it. One device brings a patch of light, not a second south-facing balcony.
  • The placement is the most important input. A device that stands in the shade itself cannot redirect anything - hence question 3.

Take your sun times with you

See the Founders reservation Refundable reservation from €49. EU delivery after certification (H1 2027), US after FCC authorization. This device has not been authorized as required by the rules of the Federal Communications Commission. This device is not, and may not be, offered for sale or lease, or sold or leased, until authorization is obtained.