I have just went through our first winter with a four winds Honalulu model and have a few points to make. I was concerned with the limited insulation on the pump side of the tub (1/2 -1 cm) and went back to the dealer (Nash Can Spas) and they claimed this is normal construction for four winds. I was still worried so I called the manufacturer who also concurred this is normal and helps to prevent overheating of the pump (during warmer weather). Now that I went through our first winter and found our hydro bill doubled from $200 to $400 a month or about 6.60 per day (we keep our tub set at 101F), I am extremely disappointed with the tub. When we purchased it the dealer informed us it would cost between 1-2 dollars a day.
Talking to other folks I know in the area who own Jaccuzzi or Hydro spa their bills are not near what ours are.
Disappointed in Ontario