How long does life support last indoors?

Solution 1:

Life support is a part of your Exosuit, and its purpose is to keep you alive.

It's easier to understand if you think of life support as some kind of device that keeps you fed and hydrated, while your suit protects you from radiation, acid rain, and extreme temperatures. Even while indoor, you still need to eat and drink, thus life support keeps draining.

Some environments can make your life support drain more quickly than others, but there is no way to prevent it from draining at all.

Solution 2:

Life support drains at the same speed indoors. I have the level 3 upgrade (Tau) for it and I can tell you that it significantly slows down the drainage. I would say with the level 3 upgrade it lasts close to 15 minutes before empty.