I have a 2 person hot tub that is a 15amp plug and says I can upgrade to 20amp will this save on my energy cost? We run hot tub all year on screen porch and live in Wisconsin so its cold

I have no idea what they mean that it will save energy. The only thing that will save energy is to use it less or keep it cooler. Simply changing the available current will not make any difference.

In Wis keeping it warm in winter is almost futile at 120v and will run nearly constantly.

Wiring it for 50A 240v will make it run less but at a higher power. It will keep temps MUCH easier, but cost more to run.

My 2 person hot tub is a 115v 15amp and can be upgraded to a 115 20amp. Is there any energy savings if it's a dedicated line

Won't save any money. How do you plan to upgrade to a 20AMP? You could possibly try to remove the skirt for the tub and insulate the base, I did that to mine and it helped quite a bit. I wrapped the tub base with 6" fiberglass batts.

my 2 person hot tub is a 115v 15amp and can be upgraded to a 115 20amp. is there any energy savings if its a dedicated line
This is exactly what you wrote in the first post.
Hopefully you got a satisfactory answer. :confused:

I plan on upgrading to a 20amp with the help of my certfified master electrian as a neighbor. My hot tub can be 115 15amp 115 20amp 0r 115 30amp. The 30amp option will invole upgrades to hot tub though. So my neighbor said going with the 115 20amp dedicated line service will elimate the energy spikes that cause inside lights in house to dim and will be more efficant.

You may realize a few cents a month savings with the dedicated line since some of your other devices on the current line may function more efficiently. If the lights are dimming, you are pulling a lot of amps on the circuit and could cause appliances, particularly motors to burn out with reduced voltage. Still, the dedicated line will do little to save you money. You would save more by doing the insulation I recommended.

OK thanks so much. I will go to store tomorrow before dedicated service is put in since I have to drain hot tub before work is done and buy insulation. Thanks