The biogas fermentation in the countryside uses natural temperature fermentation, so the gas production of the biogas varies greatly with the season. The gas production from January to February is the lowest, generally 0.08 to 0.1 m3/(m3·day), the highest from July to August. Up to 0.2-0.3 cubic meters/(cubic-meter-day), so in the winter to take some insulation measures, it will help improve the biogas production rate.

According to China's rural conditions, the following methods can generally be used:

(1) The biogas digester is built at the leeward sunny position. The open-air biogas digester in the north must be built below the frozen soil layer. The trimixing soil can be placed on the fermentation chamber and covered with soil and compacted. The intake and discharge ports should not be overhauled.

(2) The intake, discharge port and water tank of the biogas digester should be covered. In the winter, crop straw should be used to cover 5 to 6 cm thick.

(3) Repairing biogas digesters under the pens and toilets is one of the effective methods for cold insulation. In the north, the biogas digesters should be built in solar greenhouses.

(4) Where there are conditions, solar water heaters can be used. When feeding, add some hot water to the pool to increase the temperature in the pool.

(5) Adding hot raw materials, such as vinasse, horse dung, etc., may be properly added during feeding.