How much does it cost to run a Grow Light?

My Grow Light enables me to start my seeds two to three months earlier than I would otherwise.  This means that I can eat Cherry Tomatoes in May and have bigger size Winter Melons and Pumpkins.

However, the Grow Light is cheap.  In addition to a couple of hundred dollars it cost me to buy my Grow Light system (4 T5 bulbs, each 4 feet long) ,  there is also the monthly charge for electricty.  After a very short while, the monthly costs can quickly exceed the original cost of the Grow Light.

Using a device called the Kill-A-Watt , I can measure how much electricty my Grow Light uses. 

When I connected the Grow Light to the Kill-A-Watt, I found the Grow Light costs $0.0483 per hour to run.  That's less than a nickel an hour.  That may not seem like a lot, but if I were to run the Grow Light for 24 hours per day, 7 days a week, it would cost me $34.78 a month or $423 a year!!!

I only leave the Grow Light on for 12 hours a day (6:30pm to 6:30am)  and I only use it in January and February,  so my annual cost is only $34.78.  Once March comes, I can put the seeds outside and they germinate just fine.   Similarly, I can put the seedlings outside in March without any problems.

There are also cheaper ways to run the Grow Light.  I could have gone with 2 bulbs and/or with 2 foot long bulbs.  This would have cut my monthly cost down by 50% to 75%.  

Alternatively, I could forego the Grow Light and just buy Cherry Tomato plants from the local nursery and start the Winter Melon and Pumpkin seeds in March.  But I find that the local nurseries don't stock the Cherry Tomato plants that my family likes to eat and I like having huge Winter Melons and Pumpkins.  I am willing to pay $35 a year for that luxury.  Of course, if I hadn't already spent the money on the Grow Light, I might feel differently.