# What setting polarity is and how to do it right

> Setting polarity places the compass at the centre of the house on its plan, turned to the measured facing degree. To get it right you need a plan with the true shape and size, a centre taken from the house rather than the plot, the facing degree (not the sitting) and a check of which mountain the main door falls in.

**Goal:** Lay the 24 mountains and the bagua over the plan exactly as they lie in reality, so that every later feng shui finding — which room is in which sector — is in the right place.

## What you need

- A floor plan with the correct outer walls, shape and dimensions, showing the main door.
- The home's measured facing degree, e.g. 135.4° (see How to measure your home's direction with a phone).
- For multi-storey homes: the ground-floor plan.

## Steps

1. **Check the plan.** Make sure the outline of the house has the right size and true shape, including missing corners and projections.
2. **Find the centre of the house.** For a rectangle, the centre is where the diagonals cross. For L-shaped or many-sided homes, it must be computed from the actual shape. Use the centre of the house, not of the plot.
3. **Set the facing.** Enter the facing degree — the direction the main door looks out to. The facing bar on the plan must point to the main door.
4. **Check the main door.** See which mountain the main door falls in and compare with your field reading. If the main door ends up on the sitting side, you may have entered a value 180° off.
5. **Use one facing for the whole house.** Upper floors belong to the same house and use the ground-floor facing.
6. **Run the feng shui check.** After setting polarity, run the feng shui check. After major changes to the plan, check again.

## Common mistakes

- Taking the centre of the plot instead of the house.
- Entering the sitting degree instead of the facing — every sector is reversed.
- A plan at the wrong scale or missing a cut-out corner, shifting the centre.
- A different facing on each floor of the same house.
- Editing the plan without re-running the feng shui check.

## Do it in Home Check

1. Tap “Projects”, then tap a project in the list to open its plan.
2. Tap “Set polarity”. If you measured on the compass screen, Home Check uses the reading you confirmed.
3. Home Check finds the centre from the shape of the plan and lays the 24 mountains and bagua over the drawing.
4. When a new reading differs from the saved one, the assistant asks which to use. When the plan changes, the app reminds you to re-check the feng shui.

## Questions

### Does the centre include balconies and yards?

Usually the centre is taken from the part of the house inside its outer walls; balconies and open yards are generally excluded. Schools differ, so agree on this with your feng shui master.

### Does an error of 2–3 degrees matter?

In the middle of a mountain it matters little; near the boundary between two mountains, a few degrees can change the mountain. Measure carefully when the degree is close to an x.5° boundary.

Terms in this guide: [Set polarity](https://myhomecheck.ai/learn/glossary/set-polarity) · [Center palace](https://myhomecheck.ai/learn/glossary/center-palace) · [Sitting and facing](https://myhomecheck.ai/learn/glossary/sitting-and-facing) · [Nine palaces (Lo Shu)](https://myhomecheck.ai/learn/glossary/nine-palaces-lo-shu)

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Original page: https://myhomecheck.ai/learn/guides/set-polarity-correctly  
Other languages: [Tiếng Việt](https://myhomecheck.ai/vi/tri-thuc/huong-dan/lap-cuc-cho-dung/index.md) · [中文](https://myhomecheck.ai/zh/learn/guides/set-polarity-correctly/index.md)  
Updated: 2026-10-21