crad
Hopefully you will get some relief from the 80 hour work weeks soon. I'm sure the extra money is nice, but it dosen't give you much time to have a life.
Half of the fun of growing hydroponically is experimenting, though having success makes it even more fun for me. Then (as in your situation) figuring out how to do it more economically is the next goal. For me using natural light is generally the most economical (unless I want to grow lettuce during summer). But I know in your area you get snow that makes growing outside imposable during winter without a equipped greenhouse. Thus the need for experimenting with artificial lighting. Although you do need to weigh the cost of the system, vs the produce you get from the plants, it cost much more to build a
hydroponic system than it does to stick a plant in the ground or pot. So start-up cost will naturally be more in the beginning, and thus cost to grow it wont usually be able to compare with prices for the produce in the stores in the beginning.
But after a few crops it begins to pay for itself. Some biggest considerations for comparing cost to grow vs cost to buy is the time of year, as well as crop grown. Especially in cold snowy areas where all the produce needs to be shipped in. That significantly raises prices, or may even make it almost imposable to get during that time of year. Being able to grow year round is one of the biggest benefits to growing hydroponically to me. Then there's the consideration of how much to grow. (what you'll realistically eat). You don't want to spend the money to grow it, just to give it away later (if cost to grow is a concern).
If you know how much wattage the florescent lighting is using, you can compare the cost to run the florescent
lights (as well as needing more of the current florescent lights), with using stronger HID lighting. Even cost to run pumps, fans etc.. As an example: for me I pay 9.29 cents per kilowatt hour (found on the electric bill), and to run one 400 watt HID light for 18 hours a day, for 30 days would cost me about $0.67 a day (about $20.10 a month). A 600 watt HID light would cost me about $1.00 a day (about $30 a month).
Electricity Cost Calculator
so the question becomes can I get $20 worth of produce (that I like to eat) out of a 400 watt light, or $30 worth out of a 600 watt light. I don't use artificial lighting at this point, but it's my understanding that a 400 watt light is sufficient to cover a 4x4 foot space, and a 600 watt light should cover about a 6x6 foot space. Using the HID lighting would be more productive, and cost effective for taller fruiting plants like tomato's, peppers etc. (as well as higher value crops). But not necessarily so for for smaller (low light requirement plants) like lettuce. For shorter fruit bearing plants like strawberry's, or short bush variety peppers. Spacing smaller wattage HID light (like 200 watt lights) closer to the plants (they can because their cooler), and spaced apart could increase overall square foot coverage, as well as may fit the square footage (floor plan) of grow space better without increasing wattage used. As you mentioned it's about experimenting. But at least with the energy calculator you can compare the cost to run theatrical setups and designs, and before you spend the money on them.