Houses are important to astrologers because they set the stage for the expression of the energies of the chart. Houses tell the astrologer which area of life will be influenced by the planetary aspects they are evaluating.
Houses are based on our perception of the planets as they move through the sky. There are many different house systems because there are many conceptions of how to best divide the sky in a meaningful way. Whichever house system you choose, the houses relate the location and the time of the chart to the position of the signs and planets along the ecliptic (the apparent path of the sun in the sky).
The houses are fixed areas of sky and fixed areas below the ground (or the other side of the Earth). The planets and the signs move through these houses every day. Just like the Sun rises and sets, the signs and planets rise into the sky and set on a daily basis. When we cast a chart for a particular location and time, the houses show us where the planet is in this daily cycle.
Houses have a correspondence with areas of our life. House meanings come from several concepts. An important source of meaning is the house’s position in this daily cycle of birth, death and rebirth that we see so clearly with the Sun. House meanings also come from the planet associated to the house in the Planetary Joys scheme. The relationship of the house to the Ascendant (Birth, Source of Light) is also meaningful to the house description.
As there are several different house systems, there are also several different conceptions of the houses and what the signify.