Lumen (lm): unity for flux. From now on THE reference to compare lights with eachother. Flux is the amount of licht that a source beams every second.
Candela (cd): unity for illumination. The illumination is the measurement for the flux that is beamed by reflectorlamps in a certain direction.
Lux (lx): measurement for illuminance. The amount of light that is present on a certain place. Or otherwise: the part of the flux that falls in on the surface; 1 lux = 1 lumen/m².
Extra saving tips
Use as much natural light as possible, the sun shines for free.
Only illuminates where and when is needed.
Place a detector or time switch where your lights might be burning unnessecairy (hallway, basement, garage, ...). LED lights are perfect for frequent switching.
Buy quality lamps with good references.
Go for lamps with the smallest wattage and the longest lifetime for the most amount of light.
Choose lights with energy label A.
Dim lights for less consumption.
Change old halogen light bubls for your mood lights by LED lights.
Paint walls and ceilings in a light color.
Regularly dust off your lights bulbs and fixtures.
For new builders:
Take into account to provide enough windows in every room: at least 1/5th of the floor surface.
Plan you lighting at an early stage of construction.
Don't use halogenic spots in the ceiling anymore. There are more energy sufficient solutions.
Be guided by your architect or a supplier of lighting fixtures. He has dedicated software to calculate how much light you need in every room, where to put it and what kind suits you best.