Assume all the incomes will be spending on consumption.

Consumption (Heat) = Income-Consumption (others)

Now income increases sine the subsidy on heat and consumption on others remains.

 That is the ability of consumption of heat increases.

If the consumer remains to use gas, his consumption ability is remained at the same level. But if shift to other alternative, he’s benefited from subsidy.

X-axis is Income and Y-axis is Consumption.

比原来变好。可用斯勒茨基方分解，看效用水平。

做了个草图  不晓得怎么发上来