In a 90㎡ house, a wall-mounted boiler (Smyth) is used in winter. The indoor temperature is maintained at 16~20 degrees. Domestic hot water is used for bathing. The outdoor temperature is -8~-18°. The daily gas consumption is 12 ~18m?, natural gas is 1.7 yuan per cubic meter, which can roughly calculate how much natural gas is used every month. My house is also 93 square meters, so I speak from experience.