400mbps is plenty fast for almost anyone. I had 100mbps for the past 5 years (even slower prior to that) and it was fine, even with two people on zoom at the same time. They recently bumped me up to 200 and it’s more than enough. But I’m paying $87 a month which is what it costs without a contract. Worth noting that the $30/month is a two year contract with a penalty for canceling early. Also your cost will skyrocket once the contract is up. You can’t threaten to switch providers because there’s no one to switch to. I guess you could just cancel and just not have internet for awhile and then come back.

Buy your own modem and router. They bleed you dry on the rental costs and modems/routers last at least 5 years.

Eversource is alright. Your costs will mostly depend on how insulated your unit/building are. I have gas heat and my heating bill on a 1 bed is like $120/month in Jan/Feb. If you have baseboards it’s probably a boiler in the basement. If you have vents it’s forced hot air.