Nice topic choice....
For me, being in Michigan and in the middle of winter, I'm finding out it's not cheap to run my spa. My filter runs 3 times a day 2 hours each time. Heater only runs when the filtration is going or when I'm using it. Since I'm not a metric guy, and I'm lazy, I'll give my dummy american numbers. My spa is small, only 280 gallons, 220v heater. As of now, in the winter months, my bill is avgeraging an extra $70 per month than what I am used to. A few months I have hit $100. This came when I filled it and ran the heater for a long time to get it to temp. Air temps in Michigan have been mild until the past two weeks, I'm cringing as to what next month's bill will be. I keep my tub at 104 degrees and air temp has been around 32-40 degrees. Like I said though, the past few weeks it's been freezing here. Highs have been around 6 degrees and lows below zero. My bill is actually alot higher than what I was told as well....I was told to expect and extra $30 a month LOL Hope this helps.