How Much Sun Does My House Get? Map One Point at a Time

Check sun direction over a house, compare summer and winter, and distinguish daylight from direct sun. Includes a worked shadow example and a site-check worksheet.

Last reviewed September 20, 2026

A house does not have one sunlight total. A kitchen window, a balcony floor and a garden bed can receive different direct sun at the same moment. Start by choosing the exact point and the question: direction, direct-sun duration or light through a window.

Inputs for a useful comparison

Record the point coordinates, local time zone, date, receiver height and nearby obstacle dimensions. For a window, record its facing direction from true north and its width, height and sill. Keep estimates labeled separately from measurements.

1. Locate the surface, not just the address

Search the address and check the result type. Zoom in, choose Move pin and place it on the actual garden bed or window position. A city result is useful for regional solar direction, but insufficient for nearby shade.

Satellite mode supplies regional geographic context from a dated Sentinel-2 mosaic. It cannot resolve every roof edge. Use a measured position when a few metres change which side of a wall the point occupies.

2. Compare the dates that affect your routine

Keep one local clock time and select Compare dates. Inspect June and December, then the months when you will actually use the space. In the Southern Hemisphere, June is winter.

For breakfast light, hold the local breakfast time. For a simultaneous event at two locations, use Detailed comparison with the same UTC instant. These policies answer different questions; daylight-saving transitions can change the result.

3. Add the blockers and keep their uncertainty visible

Context can load a coarse terrain horizon and building ways within 300 m. Buildings with an explicit height use that value; building:levels is converted at 3 m per storey and labeled as estimated. Missing heights are skipped.

Inspect imported screens, replace estimates with measurements and add trees or walls the dataset lacks. An empty import is missing evidence, not proof of an open horizon. Terrain sampling affects modeled direct sun, while standard sunrise and sunset remain open-horizon events.

4. Use this field worksheet

Save or export one scene per observing point. Record a real observation to challenge the model, then change the uncertain input that could explain a mismatch.

Point and surface: kitchen window, balcony or named garden bed.
Date, local time and time zone; note whether the Sun is actually visible.
Obstacle: position, height, width and whether each value is measured, tagged or estimated.
Model assumption to test: receiver height, window direction, missing tree, ridge or overhang.
Compare a second season; record a new observation instead of carrying one day’s conclusion across the year.

5. Choose the next calculation

Sun direction answers where to look. The shadow calculator answers how far a specified object’s shadow can extend. The garden calculator estimates direct sunlight at one outdoor point, while the window calculator tests a vertical opening.

For photographs, Find alignment supplies geometric time windows around a target bearing and selected solar elevation. A matching window does not promise a clear view or colorful sky.

Method and a worked example

First inspect solar direction on the map. Then test the ray against the point’s modeled horizon and finite vertical screens. A window additionally requires the Sun to be in front of the window plane. Daily direct-sun totals use elapsed intervals no longer than two minutes; sunrise-to-sunset duration alone is not a property sunlight estimate.

Suppose a wall is 10 m high on level ground and the receiving point is 15 m beyond it along the shadow direction. At 30° solar elevation, the wall’s geometric shadow is 10 / tan(30°) = 17.32 m and can reach the point. At 45°, it is 10 m and cannot. A narrow wall or an off-axis point can remain unshaded even when the numeric length exceeds 15 m: direction and width matter.

How to interpret the comparison

Report “modeled direct sun at the garden point on this date,” not “this house gets six hours of light.” Diffuse skylight can brighten a room when direct sun is blocked. A zero-hour result is not a measurement of indoor brightness.

Limits of the estimate

Map imagery can be old; an address can resolve to a street or administrative area. Open building heights are incomplete and storey-derived heights are estimates. A sampled terrain horizon may miss narrow ridges. Roof overhangs, trees, slopes, weather and window transmission need separate consideration.

What to do next

Open the sun-path map to locate the point and compare dates. Use the garden calculator for an outdoor horizontal point or the window calculator for a vertical opening. Save a scene before changing assumptions so the comparison is reproducible.

Questions about this method

Is sunrise to sunset the number of sunlight hours my house gets?

No. That interval describes standard open-horizon daylight. Direct sunlight at a particular surface also depends on direction, terrain, nearby obstructions and, for a window, its facing plane.

Can I check sunlight before visiting a property?

You can make a preliminary geometric estimate with the location, dates and documented dimensions. Missing heights or vegetation can change it substantially. Keep the assumptions and verify the important ones on site.