You will need
  • - special formula for calculating power lighting;
  • - data on power density for lighting (R).
Use the special formula for approximate calculation of power lighting. It has the form: P=pS/N, where p is power density for lighting, measured in W/m2 ( 20 W/m2 – average), S denotes the area of the premises calculated in square meters, N is the number of lamps. However, such a calculation can give a rough result. As the requirements for illumination of various premises quite different, depending on the type of premises (for example, in the hallway or the bathroom light should be less than in the living room). Also the lamps depending on the type also deliver different quantities of light (such as fluorescent and halogen).
For a more accurate calculation of illuminance of a room, using the formula P = pS/N, keep in mind that the value of p should not take the average value (20 W/m2), and in accordance with the value of power density for lighting for this type of room. There are special tables, calculations of indicators of specific power for lighting, taking into account the type of premises and type of bulb. You can find them online, on sites dedicated to this issue.
When calculating the power of lighting, take into account that it can be shared – basic (chandeliers, pendants, etc.) and local (floor lamps, wall lamps, floor lamps, tochechnyi etc). And when you need to calculate the illuminance, regardless of whether you do a calculation of the local or the main lighting, you need to consider what different lamps give different luminous flux, brightness and intensity.
For the main lighting, use chandeliers and ceiling lamps which have lampshades made of opal or frosted glass or lamp with frosted glass. Light streams in them a soft, broken. Such a light source can illuminate the whole room evenly.
If you want to achieve the opposite effect, use lights that have a reflective surface or use in such lamps the lamp with a reflective surface. Reflective layers can be applied closer to the base on the lamp bulb. Use this light to illuminate a certain area of the apartment.