Which way does my room face?
"Which way does it face?" is the first question anyone asks about a room, and the answers people give are usually guesses. Here are three ways to get it right, in ascending order of reliability.
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What the bearing means
A window's orientation is the compass direction you look when you stand at it and face out. A window you look south through is a south-facing window, and the room behind it is a south-facing room. That is the whole definition — but note it is the direction you look outward, not the direction light travels, which is the opposite. It is an easy thing to get backwards.
Bearings, not just letters. North is 0°, east 90°, south 180°, west 270°. Most real houses are not aligned to the cardinal points, so the useful answer is usually a number like 212° rather than "roughly south-west". The difference between 180° and 212° is about an hour and a half of when the sun arrives.
Method 1: your phone
Every modern phone has a magnetometer. Open the compass app, stand square in the window opening looking out, hold the phone flat, and read the bearing.
Two things ruin this. Magnetic compasses are pulled off by steel — radiators, steel window lintels, reinforced concrete, the metal in a laptop — so step back from anything ferrous and take a few readings from slightly different spots. And phone compasses need calibrating; if your readings wander by more than a few degrees between attempts, wave the phone in a figure of eight and try again.
Also check whether your app reports true north or magnetic north. Sun calculations use true north. In most of the UK and the eastern US the difference is currently small — a degree or two — but in parts of the western US and Canada it can exceed 10°, which is enough to matter.
Method 2: a map
Usually the most accurate option, and it needs nothing but a browser. Find your building on a satellite map with north at the top, zoom in until the roof outline is clear, and identify the wall the window sits in. The direction perpendicular to that wall, pointing away from the building, is your bearing.
If you want a number rather than an eyeball estimate, draw an imaginary line straight out from the middle of that wall and see where it points relative to the map's north arrow. Terraced and semi-detached houses are easy, because the whole row shares an orientation.
Method 3: the sun itself
The most reliable method of all, because it uses the thing you actually care about. On a sunny day, wait until the sun is shining squarely through the window — the moment when the sunlit patch on the floor is directly in front of the opening rather than off to one side. Note the time.
Then look up the sun's bearing at your location for that exact moment. That bearing is your window's orientation, to within a couple of degrees. It automatically accounts for true north, ignores magnetic interference, and cannot be fooled by an oddly shaped building.
A shortcut version: note the clock time the sun first appears in the window in the morning or last leaves it in the evening, and compare against the sun path diagram for your location.
What each orientation is like to live in
These descriptions assume the northern hemisphere; south of the equator, swap north and south.
| Faces | Direct sun | Character |
|---|---|---|
| North | Little to none; a sliver at each end of midsummer days | Even, cool, unchanging light. Prized by painters and anyone with a screen. Cold in winter. |
| East | Dawn until roughly midday | Bright early, done by lunch. Excellent bedrooms and breakfast rooms; disappointing for evenings. |
| South | Mid-morning to mid-afternoon, all year | The most total light and the only orientation with reliable winter sun. Can overheat in summer without shading. |
| West | Early afternoon until sunset | Bright, warm evenings and long golden light. Good living rooms; hot in summer and dark in the mornings. |
The in-between bearings matter most
Almost nobody has a genuinely cardinal window, and the diagonals behave quite differently from the compass points either side of them.
- South-east is arguably the best all-round orientation for a room you use in the morning and afternoon: it gets sun from soon after dawn until mid-afternoon, and it picks up winter sun that a due-east room misses entirely.
- South-west gets the most heat of any orientation, because it collects afternoon sun when the air is already warm. Wonderful in April, punishing in July.
- North-east and north-west both get a genuine slice of direct sun in high summer — early morning and late evening respectively — and essentially none between October and March.
Rather than reason about this, set the bearing and look at it. The room tool projects the window onto the floor, so you can watch the sunlit patch move across the room hour by hour and see how many hours of direct sun each month brings.