Churches are a gathering of people, including all ages, meeting to carry out religious actions and providing for a selection of worship, often will also include institutional learning of young people along with caring of babies with nursing mothers and all the other supporting roles within the church.

The difference in denominations can make a difference in the way a church is designed as some are more traditional requiring the configuration allowing for the main hall where the congregation would sit allowing for a pulpit and altar with a nave but all of them require an entrance foyer or hall where the public first enter the building in expectation of what they can give to the one they have come to worship or participate in religious actions.

Others require simply a stage and a hall where people can sit or stand while a stage provides the visual space raised above the hall to allow for those at the rear of the hall to see more clearly what is taking place with both entrainment and education by way of preaching and teaching and music.
Some churches have specific requirements in their religious festivities or day to day actions sometimes involving the congregation and other times only those who act as the leaders to the church action while the congregation then becomes only the observer.

Churches still require heating and as each person radiates about the same as a 100 watt light bulb in an hour. That means a group of 300 would generate enough heat to warm the room without the need for any heating.

Light plays an important part in the design of churches also with the play of light through the huge Cathedrals of times gone by to the modern churches of today light is always important and the warmth generated by carefully designed buildings that allow the suns warmth to generate to building it can keep the church to an ambient temperature all year round. Bearing in mind that services are usually held mid morning until midday it could make sense to prevent low light from entering the interiors at the time.