The Hengyang Municipal Bureau of Natural Resources and Planning, the Hengyang Municipal Housing and Urban-Rural Development Bureau, and the Hengyang Municipal Development and Reform Commission jointly released the "Notice on Implementing Valuation of Commodity Housing Sales Based on Usable Building Area in the City." Starting from January 1, 2025, the sale of commodity housing in Hengyang, Hunan Province will implement pricing based on usable building area. Usable building area (exclusive building area) consists of three parts: the usable area of the house, the area of the inner walls, and the area of the inner balcony. Real estate development companies must agree with homebuyers to calculate the price of commodity housing based on usable building area (exclusive building area) when signing online contracts, and the terms relating to area disputes must specify that usable building area and its price shall serve as the basis for resolving area disputes.