The trouble with "south-facing"
- The building and the window are not the same thing. In corner units, L-shaped blocks and towers, two flats in the same building can face south-east and south-west.
- There is no agreed width. On an 8-point compass, south covers 157.5° to 202.5°, but listings sometimes call a south-east window (around 135°) "south-facing".
- Direction means little if something blocks it. A south window behind a taller neighbour may get no winter sun at all.
3 ways to check
| Method | Good at | Limits |
|---|---|---|
| Site plan or floor plan | Check before you visit; plans use true north | May not show the north arrow or the unit you are viewing |
| Satellite view in a map app | Rough window direction from the roof outline | Eyeballed angle, hard with irregular buildings |
| Phone compass on site | A number, standing at the actual window | Errors near steel and appliances; reads magnetic north |
The reliable order: get a rough idea from the plan, then confirm the number in front of the window.
Reading the number
A phone’s magnetic sensor measures from magnetic north, while plans and maps use true north. The gap (magnetic declination) depends on where you are. More on that in magnetic vs true north.
| City | Declination (2026) | Due south (180° true) reads on a phone compass as |
|---|---|---|
| New York | about -12.5° | about 192° |
| Toronto | about -10.1° | about 190° |
| London | about +1.2° | about 179° |
| Los Angeles | about +11.3° | about 169° |
| Sydney | about +12.8° | about 167° |
Measuring with Compass Camera
Below are real screens from the Android app "Compass Camera". Because you measure through the camera, the photo itself shows what the window looks at.
Stand square to the window
Stand in the middle of the window, facing straight out, and hold the phone upright. The bearing tape at the top and the large number at the bottom (for example 186° S) show where the camera points. Window frames are often metal, so take a step back before you read.
Turn on Stamp bearing and take one per home
In the capture settings, turn on "Stamp bearing" to burn the bearing and time onto the photo. Make a set such as "Viewings" and take one shot per home, so you can tell them apart after a long day.
FAQ
Can I measure from inside the room?
Reinforced concrete, fridges and speakers can pull a phone compass off by several degrees or more. Open the window or step onto the balcony, and take two or three readings to see if they agree.
Is south-east or south-west better?
It depends on how you live. South-east gives morning light and avoids the hottest afternoon sun; south-west keeps the living room bright later. Get the number right, then decide.
Compass Camera
No sign-up, no location permission, and your photos stay on your phone. Free on Android.