Knowing which way your roof faces is the first step when considering solar panels. The direction, or aspect, of your main roof slope determines how much sunlight your panels would receive across the year. There are four practical ways to find out, ranging from a 30-second check on your phone to a look through your property documents.

Method 1: Compass App on Your Phone

Every modern smartphone has a built-in compass sensor. The process is straightforward, though you need to stand on or directly below the roof slope you want to measure.

  • Open the Compass app on your phone (built into iOS; search "compass" on Android for the Google Maps compass or a free third-party app).
  • Stand in the garden or on the pavement directly in front of the roof slope you want to check.
  • Hold the phone flat and horizontal at waist height.
  • Point the top edge of the phone directly at the roof slope, as if the phone were a compass needle aimed at the roof face.
  • Read the bearing shown on screen. 0° or 360° is north, 90° is east, 180° is south, 270° is west.
  • If your reading is between 135° and 225°, your roof has a south-facing aspect. Between 90° and 135° is south-east to east, and between 225° and 270° is south-west to west.

One note of caution: compass apps can be affected by nearby metal objects, power lines, and even reinforced concrete. If the reading seems inconsistent, move a few steps away from the building and try again. Taking two or three readings and averaging them is good practice.

Method 2: Google Maps Satellite View

Google Maps satellite view is arguably the most reliable free method because it removes the guesswork of standing in the right spot. You are looking at the roof from directly above, so you can see the ridge line and the angle of each slope clearly.

  • Open Google Maps and search for your home address.
  • Switch to satellite view using the button in the bottom-left corner of the screen.
  • Zoom in until your roof fills most of the screen.
  • Google Maps always shows north at the top of the screen. The slope that faces the bottom of the screen (towards the south of the map) is your south facing slope.
  • Identify where the ridge line runs. If the ridge runs east-west, one slope faces south and one faces north. If it runs north-south, you have an east and a west facing slope.
  • If the ridge runs diagonally, estimate the angle: closer to the bottom of the screen means more southerly, closer to the left side means more easterly, and so on.

Google Maps satellite imagery may be several years old and will not show recent roof extensions or new buildings nearby. For most purposes this does not matter, but it is worth bearing in mind if your property has changed recently.

Method 3: House Deeds, Plans, or an OS Map

Older methods still work reliably. If you have a copy of your property plans or title register documents, these will typically include a site plan drawn to scale with north indicated by an arrow. Comparing the orientation of the building footprint to the north arrow gives you the roof aspect.

Ordnance Survey maps are another option. The OS maps on gov.uk are free to view and show building footprints accurately, always with north at the top. Search for your postcode, zoom in to your property, and use the same logic as the Google Maps method above.

This approach is particularly useful for properties with complex roof shapes or where the satellite imagery is unclear. A measured plan gives you a more definitive answer than a visual estimate from above.

Method 4: Use Our Free Roof Orientation Tool

The quickest and most convenient option is to check which way your roof faces using our free tool. Enter your postcode and the tool uses mapping data to identify your property and calculate the orientation of your roof slopes. You get an instant result that also tells you the estimated solar potential for your specific roof, without needing to stand in the garden or open a satellite map.

The tool is particularly useful if you want to compare multiple slopes on the same property, for example a main rear slope and a smaller front slope, or if you have a property where the roof is difficult to see from the street.

The most important slope to check is the one with the largest unshaded area. A small south facing section above a dormer window is not as useful as a large west facing slope with no obstructions. Think in terms of usable area, not just compass direction.

What to Do Once You Know Your Orientation

Once you have confirmed the direction your roof faces, you can assess the solar potential more realistically. South, south-east, and south-west facing roofs are all considered good candidates for solar panels. East and west facing roofs are also viable, typically generating approximately 80 to 85% of what a south facing installation would produce. Our guide to whether your roof needs to face south for solar covers the output differences in detail.

If you have an east-west property, where one side faces east and the other west, it may be worth considering panels on both slopes. Read our article on solar panels on east and west facing roofs to understand how that setup works and what output to expect.

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Does the compass on my phone give an accurate reading for my roof?

Smartphone compasses are generally accurate enough for this purpose, but they can be affected by interference from metal objects, vehicles, and building materials. For the most reliable reading, stand several metres away from the building, hold the phone flat and horizontal, and take two or three readings to confirm they are consistent. If readings vary by more than 15 to 20 degrees, try moving to a different spot.

My house is at an angle to the road. How do I check the roof direction?

The road orientation does not directly tell you the roof direction if your house sits at an angle. The satellite view method is most reliable in this case: open Google Maps, switch to satellite, and look at which way the roof slopes face relative to north, which is always at the top of the map. Alternatively, use our postcode tool, which calculates orientation from mapping data rather than the street layout.

I have a hipped roof with four slopes. Which one do I check?

On a hipped roof, check the largest slope that has clear sky exposure with no significant shading. Usually this is the rear or front slope with the greatest area. Solar installers will assess all usable slopes and recommend panels on whichever combination gives the best return. The postcode tool or a satellite map can help you identify which slopes are largest before speaking to an installer.