The single biggest challenge running through the winter is the possible loss of power during operation. Pipes can freeze up in no time without circulation.

We build stand alone and attached spas on builds and my clients always ask about running the spas through the winter.

I strongly recommend to them to consider a stand alone generator whether it's for the entire house or solely the filtering equipment. Generators will require a fuel source to operate either natural gas or propane.

If you decide on a generator, I would use that fuel source to run a gas fired heater as well.

Electric heaters take a long time to bring water up to temperature. They also require a lot of power just to operate.

As far as costs are concerned, prices are regional and differ area to area. Costs will also vary based on your use and the ambient temperatures during the winter.

Hot tubs are not for those worried about a couple of extra hundred in utility bills. That is for a temperate time frame. Most people winterize them rather than pay quadruple that to keep them going through winter.

Something that hasn't been said: A cover can help "hold in heat". It may not keep things toasty warm in the Vermont winter, but it will help.