How much electricity will my growroom use? This is a commonly asked question by most new growers. The majority of electrical items supplied by Dampkring Growshop will state either in the instructions or more often on the unit itself how many Watts are being used. For example the RVK 100A1 fan uses 35 Watts per hour or .35KW per hour.
A unit equals one-kilowatt hour, this means:
1 unit = one thousand Watts used for 1 hour
Somewhere on your bill, or available by contacting your supplier, will be how much you are paying per unit (this is usually displayed as euro cents per unit). These prices vary between different suppliers. Nearly all suppliers run some type of discount scheme (such as where the hours between one a.m. and eight a.m. are slightly less than half price). Check what schemes your supplier runs and take full advantage.
So to calculate the cost of running your grow room simply work out how many Watts will be used and for how long and then multiply by your unit price. A fair average price in Holland at the moment is about 10 cents per unit. A few examples are below.