BASIC INFORMATION
Compact fluorescents are close relatives of the 4ft tube fluorescents, commonly used in shops and schools for their white, soft light that does not cast any defined shadows. These lights are long tubes, usually 4ft long, filled with a gas that releases a photon of light when excited by electricity. The electricity is passed through the tube from the metal sections at either end, thus exciting the gas within and releasing photons of light. These lights must have a 'starter' which gets the light going initially, unlike incandescent which can just be turned on and off without one. Regular fluorescents usually emit 18w of light per tube, and cannot be plugged straight into a wall socket.
Compact fluorescents, on the other hand, are made for use in regular light sockets, and can easily be installed by anyone with basic handyman skills. Compact fluorescents are usually around 8inches long (not including the ballast, which usually adds about 3 inches to the total length) and emit minimal amounts of heat from the globe itself. Most of the heat emitted from a compact fluorescent comes from the ballast. These lights are usually between 8w and 27w, although some variation may occur between brands and uses.
The main reason people choose CF's over regular fluoro's is their compact ability! They are very 'movable' and can be positioned almost everywhere. They put out MUCH more light than their bigger cousins, while using only a fraction of the space.
Some of the many varieties of compact fluorescents.
Image contributed by: Locutus
NON-CULTIVATION USE OF COMPACT FLUORESCENTS
If you're running a large grow setup, and you're concerned about the spike in electricity, replace your regular light bulbs with compact fluoro’s around the house! They give off the same light, using only a fraction of the electricity. If you're running a HID light, and the electricity increase could kill you financially, or you're just worried about LEO, it might be a good idea to replace incandescent with compact fluoro’s. As an example, a 100w incandescent uses most of its energy giving off heat. If you replace all these 100w incandescent bulbs with ~20w energy saving compact fluoro's, you can dramatically reduce your energy bill, and help the environment at the same time. In fact, I recommend changing all your lights to CF's regardless of your growing situation, as they will save you $$ in the long-term, and save the environment.
The advantage with these lights is that the conversion from incandescent isn't complicated! Simply un-screw the old bulb, and screw in a compact fluoro! Done! You're on your way to energy saving paradise!
THE USE OF FLUORO'S FOR GROWING CANNABIS
Every grower has, or still uses these lights. Although they don’t even come close to the results from a HID light, they do however provide a cheap alternative for a newbie 'dabbling' in the fine art of growing. Instead of spending hundreds of dollars on an HID light, a newbie can purchase a compact fluorescent for a few bucks, and still have money for a coffee on the way home.
These lights are also excellent for starting seedlings and clones, as their cool light will not dry out the soil as fast as an HID. They have a low intensity, and are gentle on newly germinated seedlings, and are great for clones as they wont dry them out or give them too much of an early blast.
Compact fluoro's are also great for stealth grows, as they can be kept about 1 inch from the plants, and do not require extensive heat ventilation due to their warm operating temperature.
WHERE CAN I PURCHASE THESE LIGHTS?
Most lighting stores will sell them, but watch out, prices are very different depending on what type of shop you get them at! As lighting shops only sell lighting equipment, their prices can either be high or low, it really depends on the type of lighting shop it is. A designer lighting shop may end up being much more expensive, as they tend to be more directed towards the upper-class designer type customer, which extra $$ to spend. Hardware’s sell them, but their variety of lights is usually limited. Electricians, and assorted electrical shops will sell them, and this is most likely where you will get the best range and the best prices. My advice to you is, shop around! You wont regret it when you can save around 30% per light.
WHICH TYPE OF COMPACT FLUORESCENT LIGHT TO CHOOSE
For anyone growing cannabis, it is pointless to buy a weak light. Given the option of 8w, 15w and 27w, you would be stupid not to buy the 27watt, as they are more or less the same price. Compare the lumen output of each of the bulbs, different 27w bulbs may have different lumen outputs (depending on the manufacturer) and as with everything, the more lumens the better. You will also be given 2 options, the screw method of fitting, or the bayonet method (push and turn). My preference is the bayonet fitting. Make sure that you choose the right one for your socket! Also, do not choose a regular compact fluoro. Pick the one with the energy saving feature (will be explained why later on in the document). Now, for vegetative growth you should choose the 'cool white' light. This is also acceptable for flowering, but a 'warm white' light will be better as it is stronger in the red end of the light spectrum which is more suitable for flowering.
Compact fluorescents are close relatives of the 4ft tube fluorescents, commonly used in shops and schools for their white, soft light that does not cast any defined shadows. These lights are long tubes, usually 4ft long, filled with a gas that releases a photon of light when excited by electricity. The electricity is passed through the tube from the metal sections at either end, thus exciting the gas within and releasing photons of light. These lights must have a 'starter' which gets the light going initially, unlike incandescent which can just be turned on and off without one. Regular fluorescents usually emit 18w of light per tube, and cannot be plugged straight into a wall socket. 
