Significant Battery Drain Despite Shutting it down

I will make my question straight to the point hopefully someone can give me some insights to why this is happening.

my Macbook Air just lost 20% despite charging to to 100% before turning it off and leaving it on the desk.

12am Nov 14th = 100%

6pm Nov 15th = 80%

i turned on the macbook air again at 6pm 15th of November and it says 80%, it has lost that much while off.

This is not normal because my 5-year old Macbook Pro 2015 loses like 5-7 percent in one day when off.

Can someone help me this my issue?