A kilowatt hour is not like a mobile phone but wouldn't it be nice. :-) It costs the same day and night. You will run into problems exposing your plants to light 24/7. I also would not be impressed with the results of a single overdriven 40 w tube.You will get better results with supps working in tandem with your south window. Most of us on the board use 4 tubes. That has not been quite enough and many of us have added cfl's to tubes. Overdriving may give you a boost but certainly not that significant. If you are simply using supplimental lighting sans window, (for you at night) you would need 3 times the amount of tubes/cfl's to run at night. There have been numerous discussions over the years on this board about light. The discussions were predicated upon the idea of using artificial light in tandem with a window, not alone. Running at night or without a window requires a substantially different amount of lighting. About 3x more than one would use with a window. If you are concerned about costs, tubes are not nearly as energy efficient as cfl's. If you would like to add heat, 42w cfl's and up will do the trick. Its not necessary to get into the cost of gas lighting. 23w really don't produce significant heat unless you are running numerous. At that point you are better off to invest in 42's or 85's For shelving it is rather easy to use the larger cfl's. Shot in from the sides if you are also going to use tubes or installed from the front. I have 1 larger shelf that has 2, 42's, an 85w and 4 4watt tubes. My orchid room is 78º day and 60 nights. NO heat vent is open in the orchid room. Kelvin rating is colour. 5000-6500 is optimal. 23w usually are 2500 and lower, usually around 1700 as I recall. Not really great, very yellow. There have been numerous discussions about large cfl's and there have been pics posted on these threads. You may want to do a GW search for 85w cfl's and "big bertha 85w cfl" (Our nick name for the 85w cfl). I've used just about everything tubes, grow lights cfl's. The results are absolutely incredible. Incadescents can be used in tandem with cfl's they would be tough on shelves. The would need to be at a distance of 2' or more. Take a look at this set up, moreover take a look at the plants!: http://forums2.gardenweb.com/forums/load/orchids/msg1122041017472.html?9 http://forums2.gardenweb.com/forums/load/orchids/msg1008215420604.html Plant leaves turning red is not a sign of bulb stength. It means that the plant has been under-light. Plants that continually turn red or violet means they are not getting enough light. Phal leaf burn is white Clara

"Fluorescents (HO T5's) I am told by some can provide enough light providing the light source is very close to the plants to allow plants to grow well (short nodes between leaves) and even flower/fruit (using both cool and warm bulbs)" This is true. The reason others oppose this setup is because HID lighting gives you better yield and so HO fluoros seem like a waste of time for them. However, you'll be more than happy with HO fluros if you utilize them correctly. DLI (Daily Light Integral) is important. I recommend 4 to 6 HO bulbs split amongst two units. A great benefit of HO fluros is the decreased electricity costs in addition to what you mentioned.

How high you keep light above should depend on heat of that light source. If you keep incadescent bulb close to the plant, it could burn even if it is small wattage. LED and fluoro and CFL bulbs emit much less heat (some differences are there too), and while more expensive to purchase, they are longer lasting and use less energy. So if you use lights for extensive length of time/hours a day, these definitely make sense. If you have shorter plants, it may be easier to rise them on some kind of shelving or stands (whatever is possible in your situation) to bring them to level of the highest plant. If you have many plants, it would be easy to keep all of the shorter ones under one light set up while taller ones are under another set up. Obviously, not knowing your general set up, these are just ideas. I have plants arranged according to height. Some that don't fit anywhere are propped up on upturned pot , or even piece of tubing - works very well. But you may be concerned about aesthetics of it - in my case, it doesn't matter...they are not in LR or any 'public display' area. I have some grey color couplings, 3" dia that work extremely well as supports. They don't look bad at all :) being same color, and are stable.

I'm looking for bright light fixtures, preferably with the bulbs facing down since those tend to give the most light. Here's one I have and love: https://www.lowes.com/pd/Style-Selections-Tolrain-11-3-in-W-Brushed-Nickel-Standard-Flush-Mount-Light/3738219 Any other ideas of really bright ones?