GrehYug · Free Tool
Sun Clock — when does each room catch the sun?
Pick a city, a month, and your plot's facing. The dial computes the sun's real position in the sky — hour by hour, season by season — and shows which room gets direct sunlight, and when.
The dial
Plan view, north up. Rooms sit on the classic Vastu grid; the sun rides the outer ring at its true compass bearing.
Today's sun clock
For each room: when direct sun enters through its outside walls. Deeper amber = sun striking that wall more squarely. Hover for details.
Across the seasons
The same rooms on the year's three key days. Watch morning rooms trade places with evening rooms as the sun's arc swings.
| Room | Winter · Dec 21 | Equinox · Mar 21 | Summer · Jun 21 |
|---|---|---|---|
| Guest Bedroom · NW | 12:40–17:204.8 h of direct sun | 12:35–18:155.8 h of direct sun | 05:35–19:1010.4 h of direct sun |
| Living · N | — | — | 05:35–19:107.3 h of direct sun |
| Puja · NE | 07:20–12:054.8 h of direct sun | 06:25–12:105.8 h of direct sun | 05:30–19:1010.5 h of direct sun |
| Dining · W | 12:40–17:204.8 h of direct sun | 12:35–18:155.8 h of direct sun | 12:25–19:106.8 h of direct sun |
| Bath / Study · E | 07:20–12:054.8 h of direct sun | 06:25–12:105.8 h of direct sun | 05:30–12:156.8 h of direct sun |
| Master Bedroom · SW | 07:25–17:2010.0 h of direct sun | 07:00–18:1511.3 h of direct sun | 10:30–19:108.8 h of direct sun |
| Bedroom · S | 07:25–17:2010.0 h of direct sun | 07:00–17:4510.8 h of direct sun | 10:30–14:153.8 h of direct sun |
| Kitchen · SE | 07:20–17:2010.1 h of direct sun | 06:25–17:4511.4 h of direct sun | 05:30–14:158.8 h of direct sun |
1 · The daily arc
The sun rises near east, climbs through the southern sky (India is north of the equator), and sets near west. So east-wall rooms get morning sun, south-wall rooms get midday sun, west-wall rooms get evening sun — and pure north walls get almost no direct sun.
2 · The seasonal swing
Earth's axis is tilted 23.4°, so the sunrise point slides along the horizon: north-east in summer, south-east in winter. In winter the whole arc is low and southerly — south rooms soak in sun for hours. In summer it's high and long — even north walls catch a graze at dawn and dusk.
3 · How the dial computes it
Three inputs fix the sun: your latitude, the day of year (which sets the solar declination), and the hour angle (clock time corrected for longitude within IST). From these, standard solar geometry gives the sun's bearing and height; a room is "lit" when the bearing faces one of its outside walls.
Next step
Now see it on your own plot
This dial shows the sun. Your GrehYug concept layout places every room where the light and Vastu agree — sized to your plot, your city, and your facing.
Indicative result
This Vastu reading is generated from classical sources — Manasara, Mayamata, Brihat Samhita and related Shilpa Shastra — applied to the dimensions and inputs provided. Vastu is a traditional knowledge system and its interpretation can vary across schools (Tantra Samuchhaya, Manasara, Mayamata, Aparajita Pricha). Individual practitioners may give different verdicts on the same plot.
This sun clock is a concept-grade illustration. It assumes an open plot with windows on every outer wall, and ignores neighbouring buildings, trees, chhajjas and the ±16-minute equation-of-time wobble. Vastu places rooms by absolute compass direction, so changing the facing moves your main door — the sunlight pattern of each direction stays the same.
For a binding Vastu compliance certificate or remedial advice before construction, please consult a qualified Sthapati or Vastu Acharya. GrehYug provides concept-stage guidance only and makes no medical, financial or spiritual claims based on this output.