Passive houses the way to go?

A couple of days ago a heard of a fantastic house, the “passive house”. This house gets warm by the electrical things that we use and by the heat from the people living there. This would make the greenhouse gas emissions from houses to drop. Today a large part of the gases come from our houses and apartments. From that they are designed to be 20 degrees inside the house all year round. But I’m a bit sceptical about the summer months. If it’s warm outside won’t it be warm inside as well since we still use the electrical products and the people will still be there?