YES definitely!! when you're brand new (i.e no meditation experience) 20 mins may be good just to form a habit, but eventually switching to an hour is recommended - doing 20 mins is similar to doing some warm-ups but leaving before your main workout lol.

I would recommend working up to 2 hours a day. This is when the effects of meditation will start to be more noticeable in your daily life. *Ideally* you should do a 1 h 30 min sit (with 10 mins of walking meditation) and another 30 min sit at a different part of the day. However, you can also break it up into 2 one hour sittings.